100W PA/Filter companion using MRF-101
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Mathis Schmieder
Jan 1, 2020, 8:17:41 AM1/1/20
to Hermes-Lite
Dear group,
I've been working on a companion board that features an MRF-101 100W power amplifier and a 6 band low pass filter bank. It's heavily based on both Jim WA2EUJ's MRF101 EVB that won NXP's homebrew challenge and James N2ADR's filter board that you probably all know. For now it's only schematics but I'm planning on laying out the board soon. I've uploaded the design files to Github: https://github.com/mathisschmieder/HL2-MRF101
I'm sure the design contains one or the other brain fart and I'd therefore invite all of you to do a sanity check. Generally, I'm very interested in your opinions on this board! Direct link to the schematics is here.
Looking forward to your input and wishing you all a happy new year,
Mathis, DB9MAT
Alan Hopper
Jan 1, 2020, 8:59:12 AM1/1/20
to Hermes-Lite
Hi Mathis,
this is just what I'm after, I'd been hoping someone would do something like this.
73 and happy new year Alan M0NNB
Don Solberg
Jan 1, 2020, 11:09:43 AM1/1/20
to Hermes-Lite
Mathis,
This is a great project! I have been studying that amplifier design and was interested in playing around with one.
I have one request: provide an input RF connector to go directly to the RX antenna input on HL2 for Pure Signal sampling. I have implemented that on my HL2 and have really grown to appreciate Pure Signal. It would be nice to not have to run a piece of coax from a panel mount SMA connector to the HL2.
The amplifier design should be easy to replicate as it is a proven design. You will obviously have to scale up the components on the LPF board to handle 100 watts. The choice of capacitors and inductors will take some research and experimentation.
If you get the design to the PCB stage, I would be very interested in being an early beta tester.
73,
Don
K9AQ
Heikki Ahola
Jan 1, 2020, 11:40:28 AM1/1/20
to Hermes-Lite
Hi Mathis et al,
Since I became aware of the novel MRF101 I started to investigate this option of increasing my station's power level above qrp. I In addition to HF, I would like to include the magic band of 50 MHz which, in my opinion, is well below the max. frequency of this device. Furthermore, I would like to question the basic idea of using only one MRFf101 instead of a push-pull circuit. A single device is of course simpler once the requirement of harmonic suppression is fulfilled ... Anyways, I am really interested in this project after having a lot of frustration with devices like IRF501 and RD16HHF not to mention vacuum tubes in the quest of generating more power in HF and lower VHF.
73 de Heikki (OH2LZI)
Marc OLANIE
Jan 1, 2020, 12:16:15 PM1/1/20
to Heikki Ahola, Hermes-Lite
Hi Heikki
Just have a look at
http://www.m0rzf.co.uk/20W_Amplifier/
schematic is here
http://www.m0rzf.co.uk/resources/MRF101circuit1.pdf
such a design is definitely not obvious, considering impedance constraints. I think the one transistor design is safer and many proof of concept have been build so far, which is not the case of the push-pull version (and after all, the MRF300 gives approximately the same level of power… too much troubles for the same result)
@Don
Considering the caps, I’m regularly using the “quad hifreq” series made by Vishay
https://www.vishay.com/docs/45221/quadhifreq.pdf
they are less expensive than ATC caps and smaller than bulky silver-mica caps
With a handful of T68 toroids (T50 would also be ok).
Cheers
Marc f6itu
De : herme...@googlegroups.com <herme...@googlegroups.com>
De la part de Heikki Ahola
Envoyé : mercredi 1 janvier 2020 17:40
À : Hermes-Lite <herme...@googlegroups.com>
Objet : Re: 100W PA/Filter companion using MRF-101
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Matthew
Jan 1, 2020, 1:41:02 PM1/1/20
to Hermes-Lite
Very interesting.
Are you anticipating this will be possible in the N2ADR footprint? This seems like a challenge after upgrading capacitors, inductors and relays(?), especially considering heat sinking? So are you thinking it would be in a new housing with this integrated? If so... Where is everyone finding their 48 V power supplies for all these designs? It strikes me that it would be a lot neater to power these from a nicely designed RF clean switcher from the same voltage as the main PCB, rather than (likely) needing a second PSU for the radio.
On 80m and 160m separate rx antennas are highly desirable/necessary. Accounting for this on the companion PCB would be of great help for LF dxers/contesters (or people using external noise cancelling jigs).
73 Matthew M5EVT.
Tm Hatch
Jan 1, 2020, 2:03:26 PM1/1/20
to herme...@googlegroups.com
Hey,
I have been working on the same thing. Attached is the 3rd
iteration of my MRF-101 that I have tested. It plugs into the
hermes lite. Works good, but needs 48 volts before it will put
out power. I have put up to 56 volts on the drain, with 40 mw
drive. It is a good design. Have not build the 3rd iteration,
which is what I have attached. Will be testing it soon. I will
upload more pics of the built board. Also have built a low pass
filter control by the Hermes lite. It uses mica caps.
My 2 cents
Tim
WB0WUQ
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Mathis Schmieder
Jan 1, 2020, 2:07:45 PM1/1/20
to Hermes-Lite
Hey Tim,
cool, I'll take a look at what you did!
As for everyone else, I'll be replying to your input tomorrow :)
Best 73s,
Mathis, DB9MAT
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Heikki Ahola
Jan 2, 2020, 5:37:46 AM1/2/20
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Hi Marc et al,
The one-transistor design is definitely simpler and more straightforward, no doubt about that. I was only slightly concerned since most designs I have studied have been push-pull ...
A question about the rf power-proof capacitors: the voltage required for 100 W level and a good source for purchasing small amounts. I am also interested if any simple means of estimating/measuring the nominal voltage exists. I happen to have a bunch of SMD capacitors (1206 size) with no idea of their parameters except C which is easy to measure.
I have used RS Components as my primary source of new stuff but they are somewhat limited with RF-related things. A good point for me is that no minimum purchase is required and shipping is free as long as I pick up the stuff by their local representative !
Looking forward to start this type of project in the near future,
73 de Heikki (OH2LZI)
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Marc OLANIE
Jan 2, 2020, 6:27:02 AM1/2/20
to Heikki Ahola, Hermes-Lite
Hi Heikki
The answer is « I don’t know” :- ))
You could have some ideas reading the G3XJP paper about the Picatune antenna adapter
http://sp-hm.pl/attachment.php?aid=413
In fact, using the simple Ohm law, you can easily determine the voltage across your caps, considering you already know the output power and the impedance of the “charge” (antenna etc, U=SqR(P.R) = 70V in “perfect normal conditions) (this is a rough estimation that does not consider the frequency)
But sh… appends everytime your Z is out of control : unplugged or shorted antenna, bad coax connection… voltage could reach very high values… or simply high impedance antennas (like a Zep) could create “light and heat”. The resistance/reactance ideal sweetspot of an antenna is only ideal
I wouldn’t use lower than 500 V caps. Probably 800V or more on lower frequencies just for security reasons (even if 500 V is largely within the “safe” zone)
I doubt traditional MLCC caps in 1206 format would be the best option (even if you // several 200V components). If you intend to use smd components, you’ll have to choose between silver-mica
Hi- Q or porcelain Johanson caps
https://www.minikits.com.au/Hi-Q-0805
or the Hi-Freq caps by Vishay I already mentioned
https://www.vishay.com/docs/45221/quadhifreq.pdf
(I certainly should miss some other brands and technology)
From my purely personal point of view, the Vishay caps are less expensive than Johanson/ATC/Mica caps and they offer a rather good quality factor (Q) and a wide range of voltage & capacitance. They also are easier to find, as they are sold by Digikey, Mouser and Farnell (but not RS I think)
I’m pretty sure other people on this list have better ideas
73’
Marc f6itu
De : herme...@googlegroups.com <herme...@googlegroups.com>
De la part de Heikki Ahola
Envoyé : jeudi 2 janvier 2020 11:38
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Don Solberg
Jan 2, 2020, 7:47:33 AM1/2/20
to Hermes-Lite
The capacitor are rated for DC voltage, not RF. The rule of thumb generally has been to use capacitors rated at least 4 times the anticipated peak RF voltage. Keep in mind that short high SWR excursions can push up the RF voltage.
I have build several very high power solid state amplifiers, from 600 watts to 1.5KW, but I have no experience at the 100 watt level. I had good success on the 600 watt amp with 1KV ATC capacitors. I would recommend 600 V caps for this amplifier.
73,
Don
K9AQ
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Brian Machesney
Jan 2, 2020, 4:45:54 PM1/2/20
to Hermes-Lite
Heikki,
I was unable to find a distributor that carried all the individual values I needed for an LPF project, but I found that Johanson's capacitor kits provide a cost-effective and wide-ranging assortment of values. The S111DUE ceramic capacitor kit comprises 280 pieces of size 1111 from 1pF to 1000pF at 500V and 1kV. I used these parts successfully on a 500W LPF bank for 160 - 10 meters. The voltage rating is overkill for your project, but I find the size to be very easy to work with and the Johanson caps are much cheaper than some of the competitors' products. The S111DVE appears to be identical except that the voltages are 50V to 500V; since the sizes are the same, I see no reason to go with the lower voltage parts.
73 -- Brian K1LI
Brian Machesney
Jan 2, 2020, 4:52:39 PM1/2/20
to Hermes-Lite
Brian Machesney
Jan 2, 2020, 4:56:04 PM1/2/20
to Hermes-Lite
Simulating with LTSpice is a relatively simple way to determine the voltages - and currents! - your components will have to withstand.
73 -- Brian K1LI
On Thursday, January 2, 2020 at 5:37:46 AM UTC-5, Heikki Ahola wrote:
Duncan Clark
Jan 2, 2020, 6:16:27 PM1/2/20
to herme...@googlegroups.com
In message <1c51f7fb-c265-4e2d...@googlegroups.com>, Don
Solberg writes
https://www.radio-kits.co.uk/radio-related/G4TZR_LPF/G4TZR_LPF.htm
Duncan
--
Duncan Clark
G4ELJ
Solberg writes
>You will obviously have to scale up the components on the LPF board to
>handle 100 watts. The choice of capacitors and inductors will take
>some research and experimentation.
The 'old fashioned' route:
>handle 100 watts. The choice of capacitors and inductors will take
>some research and experimentation.
https://www.radio-kits.co.uk/radio-related/G4TZR_LPF/G4TZR_LPF.htm
Duncan
--
Duncan Clark
G4ELJ
Mathis Schmieder
Jan 3, 2020, 5:01:42 AM1/3/20
to Hermes-Lite
Dear group,
On Friday, January 3, 2020 at 12:16:27 AM UTC+1, Duncan Clark wrote:
Regarding Cs and Ls, I'll start by using the components Jim suggested for his 3/7 band LPF board that he developed for his PA and that are tested and proven to work: https://docs.google.com/viewer?a=v&pid=sites&srcid=ZGVmYXVsdGRvbWFpbnxyZnBvd2VydG9vbHN8Z3g6MWU2Y2MwZTQ4YzQ3OTVhYQ - they're inexpensive and available in small (and large) quantities.
I absolutely don't anticipate this board having the same footprint as the N2ADR filter board (10x5cm), with the amount of relays alone this won't be possible. I'm hoping to fit everything on 10x10cm though, having the board sitting on top of the HL2. If all fails, 10x15cm should be enough, but I'm confident that 10x10cm will work.
Regarding pure signal: This is something I definitely want to at least try to support. What I didn't understand yet is if you can do it with the RX/TX relay fitted on the HL2 or if you have to run the HL2 board in full duplex configuration for that. I'd like to be able to switch between the 5W N2ADR board and this 100W PA without disabling the on-board relay. Maybe someone can answer this?
Regarding 50 MHz: The MRF-101 does 6m - no problem at all there - and a LPF for 6m wouldn't be a problem either. But - as far as I know - the HL2 isn't really capable of 6m/50MHz. At least not with the spectral purity it usually has?! Anyway, it wouldn't be a problem to - for example - remove the dedicated 60m filter and use the 40/30m for that and add a 6m filter. That would just be a matter of changing bits in the software ;)
As for the 48/50V power supply: Yeah, I agree that this is not optimal, I'd also much rather run the PA on the same power supply as the HL2, but I'm afraid there's just no way to do that. Most of not all state of the art RF FETs are 28 or 50V parts so if we want to use them, we just have to deal with it. The way I see it, we have a couple of different options tackling this problem:
a) Just use different power supplies, for example the Meanwell EPP-200-48 for 48/50V and whatever else you want to use for 12V. Probably not cool for portable operations where you don't have mains power to run the Meanwell brick
b) Use just a single 48V supply, like the aforementioned Meanwell brick and step down the voltage to 12V for the HL2. The step down converter could either be integrated on this 100W PA PCB or be an external module. Good care has to be taken with filtering switching noises, but it should be possible. Still not ideal for portable ops.
c) Use a high current 12V supply and step up the voltage to 50V for the PA. Again, the step up module could be integrated or on an external board - I'm leaning towards this option with an external step up module. They're cheaply available and with some filtering they should work. You'd need a 20-25A 12V supply though, but that's the case with almost all 100W rigs. Best option for portable ops, IMHO.
Anyways, I'm quite confident about the RF portions of the schematics, not so much about the logic and especially op amp part. I'd highly appreciate it if someone could do a sanity check there.
Best 73s,
Mathis, DB9MAT
On Friday, January 3, 2020 at 12:16:27 AM UTC+1, Duncan Clark wrote:
In message <1c51f7fb-c265-4e2d-85f1-a11124...@googlegroups.com>, Don
Christian
Jan 3, 2020, 6:00:17 AM1/3/20
to herme...@googlegroups.com
Dear Group,
Great project for the beginning of 2020.
Here is my small contribution about enclosure form factor for MRF101
project. Idea is if possible to keep the same enclosure form actor as
the HL2. I just found on Aliexpress this Heat-sink with same dimensions
as HL2 enclosure. May be to small ?
https://fr.aliexpress.com/af/150x97x32mm-en-aluminium-dissipateur-.html?d=y&origin=n&SearchText=150x97x32mm+en+aluminium+dissipateur+&catId=0&initiative_id=SB_20191231090528
https://fr.aliexpress.com/item/33041012630.html?spm=a2g0o.productlist.0.0.65c827168Jcm3g&algo_pvid=e21f5b85-4e14-4367-8e87-04470dea7457&algo_expid=e21f5b85-4e14-4367-8e87-04470dea7457-37&btsid=4cdeaa1b-f763-401a-af39-32c83fa07810&ws_ab_test=searchweb0_0,searchweb201602_3,searchweb201603_55
Christian F8GHE
<https://fr.aliexpress.com/item/33041012630.html?spm=a2g0o.productlist.0.0.65c827168Jcm3g&algo_pvid=e21f5b85-4e14-4367-8e87-04470dea7457&algo_expid=e21f5b85-4e14-4367-8e87-04470dea7457-37&btsid=4cdeaa1b-f763-401a-af39-32c83fa07810&ws_ab_test=searchweb0_0,searchweb201602_3,searchweb201603_55>
>> <https://github.com/mathisschmieder/HL2-MRF101/blob/master/HL2_MRF101.pdf>.
> <mailto:hermes-lite...@googlegroups.com>.
> <https://groups.google.com/d/msgid/hermes-lite/1eb1f0e1-352f-4762-bf81-f5f31b647cad%40googlegroups.com?utm_medium=email&utm_source=footer>.
Great project for the beginning of 2020.
Here is my small contribution about enclosure form factor for MRF101
project. Idea is if possible to keep the same enclosure form actor as
the HL2. I just found on Aliexpress this Heat-sink with same dimensions
as HL2 enclosure. May be to small ?
https://fr.aliexpress.com/af/150x97x32mm-en-aluminium-dissipateur-.html?d=y&origin=n&SearchText=150x97x32mm+en+aluminium+dissipateur+&catId=0&initiative_id=SB_20191231090528
https://fr.aliexpress.com/item/33041012630.html?spm=a2g0o.productlist.0.0.65c827168Jcm3g&algo_pvid=e21f5b85-4e14-4367-8e87-04470dea7457&algo_expid=e21f5b85-4e14-4367-8e87-04470dea7457-37&btsid=4cdeaa1b-f763-401a-af39-32c83fa07810&ws_ab_test=searchweb0_0,searchweb201602_3,searchweb201603_55
Christian F8GHE
<https://fr.aliexpress.com/item/33041012630.html?spm=a2g0o.productlist.0.0.65c827168Jcm3g&algo_pvid=e21f5b85-4e14-4367-8e87-04470dea7457&algo_expid=e21f5b85-4e14-4367-8e87-04470dea7457-37&btsid=4cdeaa1b-f763-401a-af39-32c83fa07810&ws_ab_test=searchweb0_0,searchweb201602_3,searchweb201603_55>
>>
>> Looking forward to your input and wishing you all a happy new
>> year,
>>
>> Mathis, DB9MAT
>>
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>> Looking forward to your input and wishing you all a happy new
>> year,
>>
>> Mathis, DB9MAT
>>
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>> https://groups.google.com/d/msgid/hermes-lite/0ac1f394-5929-4402-8963-8c5cb615532b%40googlegroups.com
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Mathis Schmieder
Jan 3, 2020, 7:25:09 AM1/3/20
to Hermes-Lite
Christian,
Thanks for the suggestion! Depending on the used power supply, this could work! If we include the 50V step up board in the setup, we'll definitely need a bigger case...
73s,
Mathis
> an email to herme...@googlegroups.com
> <mailto:hermes-lite+unsub...@googlegroups.com>.
Christian
Jan 3, 2020, 7:41:20 AM1/3/20
to herme...@googlegroups.com
Mathis,
I don't if it's a good idea but this type of module "600W Boost
Converter" could be an alternative solution to boost voltage from 12V.
https://fr.aliexpress.com/item/4000083971295.html?src=google&src=google&albch=shopping&acnt=494-037-6276&isdl=y&slnk=&plac=&mtctp=&albbt=Google_7_shopping&aff_platform=google&aff_short_key=UneMJZVf&&albagn=888888&albcp=6459788344&albag=76234907246&trgt=743612850874&crea=fr4000083971295&netw=u&device=c&gclid=CjwKCAiA6bvwBRBbEiwAUER6JXUiKrFuWiwC8Ca1uh8fk-n3MfoyNwU1v02PnZ6NTcdfgvAY8Mij3xoCCSYQAvD_BwE&gclsrc=aw.ds
See on http://www.m0rzf.co.uk/20W_Amplifier/
73s Christian
On 03/01/2020 13:25, Mathis Schmieder wrote:
> Christian,
>
> Thanks for the suggestion! Depending on the used power supply, this
> could work! If we include the 50V step up board in the setup, we'll
> definitely need a bigger case...
>
> 73s,
> Mathis
>
> On Friday, January 3, 2020 at 12:00:17 PM UTC+1, Christian wrote:
>
> Dear Group,
>
> Great project for the beginning of 2020.
>
> Here is my small contribution about enclosure form factor for MRF101
> project. Idea is if possible to keep the same enclosure form actor as
> the HL2. I just found on Aliexpress this Heat-sink with same
> dimensions
> as HL2 enclosure. May be to small ?
>
> https://fr.aliexpress.com/af/150x97x32mm-en-aluminium-dissipateur-.html?d=y&origin=n&SearchText=150x97x32mm+en+aluminium+dissipateur+&catId=0&initiative_id=SB_20191231090528
> <https://fr.aliexpress.com/af/150x97x32mm-en-aluminium-dissipateur-.html?d=y&origin=n&SearchText=150x97x32mm+en+aluminium+dissipateur+&catId=0&initiative_id=SB_20191231090528>
>
>
> https://fr.aliexpress.com/item/33041012630.html?spm=a2g0o.productlist.0.0.65c827168Jcm3g&algo_pvid=e21f5b85-4e14-4367-8e87-04470dea7457&algo_expid=e21f5b85-4e14-4367-8e87-04470dea7457-37&btsid=4cdeaa1b-f763-401a-af39-32c83fa07810&ws_ab_test=searchweb0_0,searchweb201602_3,searchweb201603_55
> <https://groups.google.com/d/msgid/hermes-lite/0ac1f394-5929-4402-8963-8c5cb615532b%40googlegroups.com?utm_medium=email&utm_source=footer
> > <mailto:hermes-lite...@googlegroups.com <javascript:>>.
> <https://groups.google.com/d/msgid/hermes-lite/1eb1f0e1-352f-4762-bf81-f5f31b647cad%40googlegroups.com>
>
> >
> <https://groups.google.com/d/msgid/hermes-lite/1eb1f0e1-352f-4762-bf81-f5f31b647cad%40googlegroups.com?utm_medium=email&utm_source=footer
> <https://groups.google.com/d/msgid/hermes-lite/1eb1f0e1-352f-4762-bf81-f5f31b647cad%40googlegroups.com?utm_medium=email&utm_source=footer>>.
> <mailto:hermes-lite...@googlegroups.com>.
> <https://groups.google.com/d/msgid/hermes-lite/cbdcd2db-7e18-4021-8261-8a7ebd02abf5%40googlegroups.com?utm_medium=email&utm_source=footer>.
I don't if it's a good idea but this type of module "600W Boost
Converter" could be an alternative solution to boost voltage from 12V.
https://fr.aliexpress.com/item/4000083971295.html?src=google&src=google&albch=shopping&acnt=494-037-6276&isdl=y&slnk=&plac=&mtctp=&albbt=Google_7_shopping&aff_platform=google&aff_short_key=UneMJZVf&&albagn=888888&albcp=6459788344&albag=76234907246&trgt=743612850874&crea=fr4000083971295&netw=u&device=c&gclid=CjwKCAiA6bvwBRBbEiwAUER6JXUiKrFuWiwC8Ca1uh8fk-n3MfoyNwU1v02PnZ6NTcdfgvAY8Mij3xoCCSYQAvD_BwE&gclsrc=aw.ds
See on http://www.m0rzf.co.uk/20W_Amplifier/
73s Christian
On 03/01/2020 13:25, Mathis Schmieder wrote:
> Christian,
>
> Thanks for the suggestion! Depending on the used power supply, this
> could work! If we include the 50V step up board in the setup, we'll
> definitely need a bigger case...
>
> 73s,
> Mathis
>
> On Friday, January 3, 2020 at 12:00:17 PM UTC+1, Christian wrote:
>
> Dear Group,
>
> Great project for the beginning of 2020.
>
> Here is my small contribution about enclosure form factor for MRF101
> project. Idea is if possible to keep the same enclosure form actor as
> the HL2. I just found on Aliexpress this Heat-sink with same
> dimensions
> as HL2 enclosure. May be to small ?
>
> https://fr.aliexpress.com/af/150x97x32mm-en-aluminium-dissipateur-.html?d=y&origin=n&SearchText=150x97x32mm+en+aluminium+dissipateur+&catId=0&initiative_id=SB_20191231090528
>
>
> https://fr.aliexpress.com/item/33041012630.html?spm=a2g0o.productlist.0.0.65c827168Jcm3g&algo_pvid=e21f5b85-4e14-4367-8e87-04470dea7457&algo_expid=e21f5b85-4e14-4367-8e87-04470dea7457-37&btsid=4cdeaa1b-f763-401a-af39-32c83fa07810&ws_ab_test=searchweb0_0,searchweb201602_3,searchweb201603_55
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Don Solberg
Jan 3, 2020, 8:07:09 AM1/3/20
to Hermes-Lite
Mathias,
I can answer your Pure Signal question. If you are running the HL2 barefoot you can get enough feedback through internal coupling, so you don't need any external hardware.
When you are running an external amplifier and you want to apply Pure Signal to the entire transmit chain, then you will need an external sampler. I use a bi-directional coupler from Wavenode that provides an attenuated RF power sample. I then further attenuate this with a step attenuator and feed this signal back to the HL2's external antenna connection. This connection is on the connector that is used by the N2ADR board, but it is not feed through the N2ADR board to the back panel. I soldered a short piece of coax to the PCB and installed a panel mount SMA connector on the pack panel. You don't need to make any modifications to the N2ADR board.
I could have replaced the step attenuator with a fixed value attenuator after I determined how much attenuation I needed, but I am keeping the step attenuator in line so I can experiment with different amplifiers.
As for the 50V requirement, I see that has a positive not a negative. If you are trying to get the best possible IMD you really don't have any other choice but to use 50V MOSFETS. A 600 watt buck booster will work real well and they are cheap on Ebay https://www.ebay.com/itm/DC-DC-600W-10-60V-to-12-80V-Boost-Converter-Step-up-Module-Car-Power-Supply-LX/323626617265?epid=20002977581&hash=item4b59a649b1:g:SvUAAOSwhspcJuwr
I am already using 50V for my amplifier, so I am ready to go.
73,
Don
K9AQ
Mathis Schmieder
Jan 3, 2020, 8:18:39 AM1/3/20
to Hermes-Lite
We'll have to check if the "600W" version is powerful enough. AFAIK, the input current on the 300W module is limited to 10-12A, which is not enough power for the MRF101. It needs about 4A at 50V (->200W), which is 16-17A on 12V. There are, however, "1200W" variants of the boost converters - http://www.aliexpress.com/item/4000028846866.html?spm=a2g0o.productlist.0.0.2b9a2a3aHYIndh . Also see https://sites.google.com/site/rfpowertools/home/power-supplies what Jim wrote about power supplies.
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Mathis Schmieder
Jan 3, 2020, 8:34:00 AM1/3/20
to Hermes-Lite
Don,
Good to hear that you have positive experience with the boost modules! I think those are the way to go!
I'm guessing the Pure Signal feedback is sampled from RF3? I'll add a SMA connector to that line and expose it!
73s,
Mathis, DB9MAT
Christian
Jan 3, 2020, 8:49:50 AM1/3/20
to herme...@googlegroups.com
This 1200W version with 20A input is smaller :
https://fr.aliexpress.com/item/32753832565.html
Christian
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Christian
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Brian Machesney
Jan 3, 2020, 9:08:31 AM1/3/20
to Hermes-Lite
I don't mean to criticize your work, Mathis, but you might want to visit RFPowerTools. They appear to sell everything needed to build a 100W PA. They also sell the board for the Hardrock-500 amplifier. The form factor may not meet your requirements, but you might decide that this could be a faster and cheaper route.
Brian K1LI
Mathis Schmieder
Jan 3, 2020, 9:12:47 AM1/3/20
to Hermes-Lite
I know, and if you check the schematics, you'll see that I specifically listed Jim's page as a source :) I even have a couple of his PA boards here lying on my desk. It's not about the fastest/cheapest route to get 100W though, I want something nice that integrates well with the HL2. Plus, I like the design work.
No offense taken :)
73s,
Mathis
Don Solberg
Jan 3, 2020, 9:15:40 AM1/3/20
to Hermes-Lite
Yes the pure signal sample needs to come in on RF3.
Don
K9AQ
dick_...@hotmail.com
Jan 3, 2020, 2:29:04 PM1/3/20
to Hermes-Lite
Don
It would be beneficial to those who will use Pure Signal to know what level of signal that you needed to inject at the RF3 or PATRRX with the psfeedback board and circuit values used. There are an abundance of signal taps and couplers that are available or easily constructed. Once the injection point and level are known it is easy to set up a directional coupler and the attenuation network for any RF output power. Much of the old Hermes original taps had from 50dB to 85db of isolation, but the Hermes/Alex configuration is different from the HL2. So it would be good to know what levels at the HL2 you and others have found to be effective.
Thanks
Dick K9IVB
Duncan Clark
Jan 3, 2020, 5:23:37 PM1/3/20
to herme...@googlegroups.com
In message <dc96c0fa-014a-4fc7...@googlegroups.com>,
dick_...@hotmail.com writes
with Pure Signal.
https://sites.google.com/view/vk1hw/homebrew/taps/rf-sampler
I use RF5 as the injection point.
Pure Signal is set to auto attenuate and works fine for me.
The only PITA is that you have to pre-adjust the value from the default
0.4072 to 0.233 in the PureSignal window every time you launch PowerSDR
else it will not work. The default value appears too far away from the
value needed for PureSignal to initially adjust. Also change the
receiver to RX4.
We really need someone with a grasp of the PowerSDR code to do some mods
specifically for use with HL2. PureSignal and correct undersampling in
the transverter section would be nice.
dick_...@hotmail.com writes
>It would be beneficial to those who will use Pure Signal to know what
>level of signal that you needed to inject at the RF3 or PATRRX with the
>psfeedback board and circuit values used.
At a power out of 400W I am using an approx -50dB coupler with my HL2
>level of signal that you needed to inject at the RF3 or PATRRX with the
>psfeedback board and circuit values used.
with Pure Signal.
https://sites.google.com/view/vk1hw/homebrew/taps/rf-sampler
I use RF5 as the injection point.
Pure Signal is set to auto attenuate and works fine for me.
The only PITA is that you have to pre-adjust the value from the default
0.4072 to 0.233 in the PureSignal window every time you launch PowerSDR
else it will not work. The default value appears too far away from the
value needed for PureSignal to initially adjust. Also change the
receiver to RX4.
We really need someone with a grasp of the PowerSDR code to do some mods
specifically for use with HL2. PureSignal and correct undersampling in
the transverter section would be nice.
Don Solberg
Jan 3, 2020, 9:30:33 PM1/3/20
to Hermes-Lite
I can't give you an exact level of the attenuation, but I should be able to make an educated guess. I am using the HF1 coupler from Wavenode https://wavenodedevelop.com/sensors/
It normally provides a +13dbm output at 1,500 watts, but I had them modify the output to provide a higher output when running the HL2 barefoot. They increased the output by about 10db. When I run a 350 watt output, I need 13 db of external attenuation after the HF1 output.
73,
Don
K9AQ
Steve Haynal
Jan 3, 2020, 11:08:07 PM1/3/20
to Hermes-Lite
Hi Mathis,
Thanks for starting this project. It looks very interesting and promising. It would be great to have a 100W PA that integrates nicely with the HL2. Other items on my wish list would be a PureSignal tap as well as hooks for EER/ET control.
73,
Steve
kf7o
Mathis Schmieder
Jan 5, 2020, 1:36:49 PM1/5/20
to Hermes-Lite
Dear Group,
I've finished the schematics and laying out the components. For now, I've got all parts more or less where I want them, see the attached images. I'll start wiring stuff soon. Unfortunately, 10x10cm was just not enough real estate and the board now is 10x15cm large. The board has an external +12V connector for a fan and for powering the HL2 and a +50V connector for driving the RF FET. +3.3V are supplied by the HL2. The Github repo has been updated with all the latest files.
Looking forward to your feedback.
Best 73s,
Mathis, DB9MAT
WA2EUJ
Jan 5, 2020, 3:42:36 PM1/5/20
to Hermes-Lite
The 600W converter is no good. Even though it's rated at "600W" the max input current is 15A (fused) so if you want 50V @ 4A and you are running on 12V input even at 100% efficiency you need 16.6A of input current. It might be OK if the input voltage were 20-30V but not 12-14V. I tried it, it doesn't work.
The 1200W red one that you see all over the place:
Works OK at 13.8V but gets sketchy at anything below 12V so might not be the best choice for battery operation.
The Meanwell EPP200-48 works fine and I've tried some of the cheap 48V 4A supplies. They were OK but the one I had did not have a voltage adjustment and made 47.5W which limited the amp to 90-95W. if you want full output you need 50V. Not that anyone could detect a difference between 90 and 100W, some people want 100W from their 100W amp.
73,
Jim WA2EUJ
Julien NICOLAS
Jan 5, 2020, 3:53:41 PM1/5/20
to Hermes-Lite
> The Meanwell EPP200-48 works fine
Is there a drawback to use it ?
WA2EUJ
Jan 5, 2020, 3:58:53 PM1/5/20
to Hermes-Lite
Hi Mathis,
I had a look at your schematics and I have 3 comments:
1. The BIAS_ON logic is reversed. At 0V, Q2 is off and the bias is present. At 3.3V Q2 turns on and shorts out the bias.
2. FT50-61's in the directional coupler are not beefy enough on the low bands they get hot enough to do some really strange stuff. FT50A-61's work great or stack two FT50-61's for each core.
3. In your band-pass filter bank, you have it setup so the highest freq band takes the longest path through the series of relays and the low freq takes the shortest.
I haven't looked at the RF performance of the relays that you selected but typically the loss through the relay is linear in frequency so it could be an issue, certainly would be if 6M were involved.
73,
Jim WA2EUJ
Matthew
Jan 5, 2020, 4:36:29 PM1/5/20
to Hermes-Lite
This looks great. I am encouraged by the separate rx connection for receive antennas. I have had a quick look and I think I am correct in my logic; if you used exttr instead of inttr, in gateware something could be done to route TX/RX switching through relays on your board and leave the TX/RX relay on the HL2 always in transmit. Otherwise, it would involve a hardware jumper to change config to separate rx antenna? This would also be of benefit to people using PureSignal? Plus, no HL2 hardware removal needed.
I like the proposed idea of 12 V switched up. It makes it a lot easier only needing 1 supply voltage. I have had mixed success with cheap switched power supply boards and RF, no amount of ferrites could cure some problems. It will be very interesting to do some tests with these on and off to see if pickup is noticed on rx. It may be of interest to design an RF quiet 48 V PSU further down the line.
I would be interested in replacing the relay with something quieter for fast and silent switching between TX and RX. Clattering relays and QSK aren't very relaxing! I imagine I would design a QSK board similar to HR50. Could you put a uFL footprint on RF3 (https://groups.google.com/d/msg/hermes-lite/2adNjpgbraA/RVjx8jZVBwAJ). Then I could route RX signal (from the TX antenna) to RF3. Then leave HL2 TX/RX relay always in transmit. Does this make sense?
Really looking forward to building on of these.
73 Matthew M5EVT.
Don Solberg
Jan 5, 2020, 4:38:25 PM1/5/20
to Hermes-Lite
Mathis,
How do plan on heatsinking the MOSFETs? In the photo it looks like you might be planning on bolting them to an end plate.
Don
K9AQ
Christian
Jan 5, 2020, 7:39:13 PM1/5/20
to herme...@googlegroups.com
Mathis,
It seems that the form factor 100x1500 is suitable for the HL2 aluminum
enclosure ? In this case here is another suitable Heatsink
(100x150x40mm) for it but MRF101 position will not be optimum. MRF101
needs to be place near center :
https://fr.rs-online.com/web/p/dissipateurs-de-chaleur/1694252/
I agree that it is better to separate RX and TX
Il could be a good idea to add a VSWR bridge like the RFpowertool design
https://sites.google.com/site/rfpowertools/home/100w-t-r-switch-with-vswr-bridge
73s Christian F8GHE
On 05/01/2020 22:38, Don Solberg wrote:
> Mathis,
>
> How do plan on heatsinking the MOSFETs? In the photo it looks like
> you might be planning on bolting them to an end plate.
>
> Don
> K9AQ
>
>
> On Sunday, January 5, 2020 at 12:36:49 PM UTC-6, Mathis Schmieder wrote:
>
> Dear Group,
>
> I've finished the schematics and laying out the components. For
> now, I've got all parts more or less where I want them, see the
> attached images. I'll start wiring stuff soon. Unfortunately,
> 10x10cm was just not enough real estate and the board now is
> 10x15cm large. The board has an external +12V connector for a fan
> and for powering the HL2 and a +50V connector for driving the RF
> FET. +3.3V are supplied by the HL2. The Github repo has been
> updated with all the latest files.
>
> Looking forward to your feedback.
>
> HL2_MRF101_back.png
>
> HL2_MRF101_front.png
> <https://www.meanwell-web.com/en-gb/ac-dc-single-output-open-frame-power-supply-output-epp--200--48> for
> <1c51f7fb-c265-4e2d...@googlegroups.com>,
> <https://groups.google.com/d/msgid/hermes-lite/7320bc7b-25cf-4f4c-93af-214618ae44c7%40googlegroups.com?utm_medium=email&utm_source=footer>.
It seems that the form factor 100x1500 is suitable for the HL2 aluminum
enclosure ? In this case here is another suitable Heatsink
(100x150x40mm) for it but MRF101 position will not be optimum. MRF101
needs to be place near center :
https://fr.rs-online.com/web/p/dissipateurs-de-chaleur/1694252/
I agree that it is better to separate RX and TX
Il could be a good idea to add a VSWR bridge like the RFpowertool design
https://sites.google.com/site/rfpowertools/home/100w-t-r-switch-with-vswr-bridge
73s Christian F8GHE
On 05/01/2020 22:38, Don Solberg wrote:
> Mathis,
>
> How do plan on heatsinking the MOSFETs? In the photo it looks like
> you might be planning on bolting them to an end plate.
>
> Don
> K9AQ
>
>
> On Sunday, January 5, 2020 at 12:36:49 PM UTC-6, Mathis Schmieder wrote:
>
> Dear Group,
>
> I've finished the schematics and laying out the components. For
> now, I've got all parts more or less where I want them, see the
> attached images. I'll start wiring stuff soon. Unfortunately,
> 10x10cm was just not enough real estate and the board now is
> 10x15cm large. The board has an external +12V connector for a fan
> and for powering the HL2 and a +50V connector for driving the RF
> FET. +3.3V are supplied by the HL2. The Github repo has been
> updated with all the latest files.
>
> Looking forward to your feedback.
>
>
> HL2_MRF101_front.png
> Don
> Solberg writes
> >You will obviously have to scale up the
> components on the LPF board to
> >handle 100 watts. The choice of
> capacitors and inductors will take
> >some research and experimentation.
>
> The 'old fashioned' route:
>
> https://www.radio-kits.co.uk/radio-related/G4TZR_LPF/G4TZR_LPF.htm
> <https://www.radio-kits.co.uk/radio-related/G4TZR_LPF/G4TZR_LPF.htm>
>
>
> Duncan
> --
> Duncan Clark
> G4ELJ
>
> Solberg writes
> >You will obviously have to scale up the
> components on the LPF board to
> >handle 100 watts. The choice of
> capacitors and inductors will take
> >some research and experimentation.
>
> The 'old fashioned' route:
>
> https://www.radio-kits.co.uk/radio-related/G4TZR_LPF/G4TZR_LPF.htm
> <https://www.radio-kits.co.uk/radio-related/G4TZR_LPF/G4TZR_LPF.htm>
>
>
> Duncan
> --
> Duncan Clark
> G4ELJ
>
> --
> You received this message because you are subscribed to the Google
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dick_...@hotmail.com
Jan 5, 2020, 9:19:47 PM1/5/20
to Hermes-Lite
Hi Mathisand Jim
FT50-43's with 20 t # 22g wire [20db Coupler] have been used in the openHPSDR Alex at 100 W for some time [160M - 6M].
You may also find Elcraft's CP1 Dual Directional Coupler manual also useful as Elcraft uses both FT50-43 and FT50A-61 for two different approaches.
https://ftp.elecraft.com/Mini%20Modules/Manuals%20Downloads/E740090%20-%20CP1%20manual%20rev%20B.pdf
You also might find Michael Ellis's paper of further interest as he describes how the circuit works and how to get other attenuation ratios.
You also might consider adding a second Directional Coupler, for Pure Signal, in series with an attenuator on the Forward output and a 50 Termination on the reflected. Depending on your choice of a 20dB or 30dB configuration you would add a 30dB or 20dB pad, respectively, to get approximately 50dB of isolation for a Pure Signal tap. Methods of connecting to the HL2 depends upon the switching system that you use for Rx.
Another thing to check is your SWR/Power Meter circuit as it appears that you are running the op-amps on 3.3V. With the 20dB Directional coupler you may exceed the power supply voltage at a 100W or so output and result in clipping.
Dick K9IVB
WA2EUJ
Jan 5, 2020, 10:22:06 PM1/5/20
to Hermes-Lite
Hi Dick,
I simulated the RFPowerTools coupler using Eagleware and built 2 with both FT50-61's and FT50-43. I found with the a more consistent output over frequency with the type 61 material, 43 might be better if you aren't worried about 6M. I didn't discover the need for the FT50A-61 until after I performed 5-10 minute, 100W tests with the amp+LPF+coupler.
For pure signal, there's no need for a second coupler. Just get rid of the two 100 ohm resistors and run the port to a SMA jack. Put a 1W 50 ohm termination on the SMA jack if you don't want to use the tap and if you do (since it probably doesn't want a +30 dBm signal), put an SMA attenuator to whatever level you need and go to your Pure Signal input. The diode detector presents almost no load to the RF.
I used this approach in the Hardrock-500 which has a 30 dB coupler and can be strapped for an on-board load or a SMA connector. It also has a negative voltage generator for ALC if anyone wants to use it.
The MRF-101 is already a very linear amp IMD -38 to -41 dB PEP, I hope someone publishes IMD data with Pure Signal running. (https://sites.google.com/site/rfpowertools/home/nxp-mrf-101/test-data)
Good point on the op-amp, the resistors I chose after the diode detector were intended for 0-4.5V output with 0-100W output and my op-amp runs rail-to-rail on 5V. You should choose a different divide ratio if you want 0-3.3V scaling, and the measured data on RFPowerTools.com is out the window.
I have a 100W diode switching module in the works for people who don't want to hear the relays and I'm thinking about redoing the Hardrock-50's ATU for the 100W level.
73,
Jim WA2EUJ
73,
Jim WA2EUJ
dick_...@hotmail.com
Jan 6, 2020, 12:08:16 AM1/6/20
to Hermes-Lite
Jim
Thanks for the tip on eliminating the second coupler. I will use that.
73,
Dick K9IVB
Mathis Schmieder
Jan 6, 2020, 3:46:47 AM1/6/20
to Hermes-Lite
Hi Jim,
Thanks a lot for your comments, I highly appreciate them! See my replies inline:
On Sunday, January 5, 2020 at 9:58:53 PM UTC+1, WA2EUJ wrote:
Hi Mathis,I had a look at your schematics and I have 3 comments:1. The BIAS_ON logic is reversed. At 0V, Q2 is off and the bias is present. At 3.3V Q2 turns on and shorts out the bias.
Damn, I double and triple checked the logic but you're probably right. I'll check again.
2. FT50-61's in the directional coupler are not beefy enough on the low bands they get hot enough to do some really strange stuff. FT50A-61's work great or stack two FT50-61's for each core.
I saw your notes on that and am planning to use either 50A or a stack of two 50s, just didn't put it on the schematics. Will do.
3. In your band-pass filter bank, you have it setup so the highest freq band takes the longest path through the series of relays and the low freq takes the shortest.I haven't looked at the RF performance of the relays that you selected but typically the loss through the relay is linear in frequency so it could be an issue, certainly would be if 6M were involved.
You're absolutely right, it makes much more sense to have the highest freq signals take the shortest path. I'll re-arrange the filters in the schematic, this way the layout can stay as it is.
Again, thanks a lot, both for your comments and for your work on rfpowertools.com. Congrats again on winning the NXP design challenge! :)
73s,
Mathis, DB9MAT
73,Jim WA2EUJ
Mathis Schmieder
Jan 6, 2020, 4:07:21 AM1/6/20
to Hermes-Lite
Dear Matthew,
I'm afraid I mislabeled the connector, it's actually connected to RF1/"Low Power TX" on the HL2. I do agree though that a secondary RX antenna connector would be highly benificial. RF3 is already exposed as the "Pure Signal Sample" connector. Maybe the Gateware could be changed to use RF3 as a secondary RX antenna during RX and as Pure Signal sampler using TX? Maybe the Gateware doesn't need to be changed at all for this? Steve, could you comment on that?
An RF quiet 48V supply would definitely be on my wish list, not sure that I'm capable to design something like that, but let's definitely keep it in mind!
Replacing the relays with PIN diodes would definitely be something I'd be interested in doing in revision 2!
Best 73s,
Mathis, DB9MAT
Mathis Schmieder
Jan 6, 2020, 4:10:47 AM1/6/20
to Hermes-Lite
Dear Don & Christian,
Don is correct, the idea is to have the rear back plate replaced by a heat sink. Having the heat sink sitting on top of the assembly would be nice, but I don't see that happening with the current layout. I put an LM35DT temperature sensor next to the MRF101 in order to switch a fan on and off. I'm planning on exposing temperature information to the HL2.
73s, Mathis DB9MAT
> Don
> Solberg writes
> >You will obviously have to scale up the
> components on the LPF board to
> >handle 100 watts. The choice of
> capacitors and inductors will take
> >some research and experimentation.
>
> The 'old fashioned' route:
>
> https://www.radio-kits.co.uk/radio-related/G4TZR_LPF/G4TZR_LPF.htm
> <https://www.radio-kits.co.uk/radio-related/G4TZR_LPF/G4TZR_LPF.htm>
>
>
> Duncan
> --
> Duncan Clark
> G4ELJ
>
> --
> You received this message because you are subscribed to the Google
> Groups "Hermes-Lite" group.
> To unsubscribe from this group and stop receiving emails from it, send
> an email to herme...@googlegroups.com
> <mailto:hermes-lite+unsub...@googlegroups.com>.
Mathis Schmieder
Jan 6, 2020, 4:20:18 AM1/6/20
to Hermes-Lite
Dear Dick & Jim,
Regarding the core material: As I see it, the layout allows for both toroids to be used. As I'm (for now) not interested in 6m with the HL2, I'll experiment with both materials and probably start with -43 as that's a bit easier to obtain than -50A. On the other hand, two -50s could be stacked. There's definitely room for experimentation here.
Regarding pure signal: My intention was to use pure signal with another external legal limit amplifier and not for the MRF101 as that's already quite clean. Therefore I didn't add a feedback tap on the board. For the sake of experimentation and because I'm also interested in pure signal IMD measurements with the MRF101, I might add a SMA or uFL connector down the line.
Regarding the op amp resistor divider values: You're right, they haven't been adjusted to the +3v3 op amp yet. I'll do that later but for laying out the board, I just put the original values in.
Definitely interested in the diode switching module, the ATU board would also probably be a nice addition.
Best 73s, Mathis DB9MAT
Mathis Schmieder
Jan 6, 2020, 6:16:02 AM1/6/20
to Hermes-Lite
Jim,
Of course you're right that my bias logic was inverted. I didn't check the actual circuit at first and just took what you wrote on your site
- Rev B - No on board current sensing, bias voltage switching at 3.3/5V logic (0V = bias off; > 3V = bias on)
which seems inverted. 0V at the N-FETs gate turns Q2 off and therefore the bias on, 3V at the gate turns Q2 on and therefore shorts the bias.
73s,
Mathis, DB9MAT
Matthew
Jan 6, 2020, 3:03:37 PM1/6/20
to Hermes-Lite
I'm not sure I follow the mislabeled connector statement, but I think we agree RF3 routes to the HL2 PCB and provides a separate RX antenna from the main TX antenna, your schematic looks correct in this regard.
A uFL footprint on the PCB trace for RF3 would provide hookup for a PIN diode board (in addition to the SMA you already have placed on the PCB). I believe your board should use EXTTR and not INTTR to allow the HL2 relay to be always in switched to TX when using this board, otherwise I don't think we can achieve silent TX/RX switching (without physically removing HL2 TX/RX relay). Do you agree?
Having looked the photos, am I correct in saying the Ethernet connector and BNC connector will be right under each other? I think provision for a whole screen between these two boards may be needed to avoid picking up noise from the HL2. I had problems in the past stacking boards with RF filters near switch mode supplies. This shouldn't affect anything at this stage, but this may limit options for the connector between the two boards to achieve the correct height?
73 Matthew M5EVT.
Julien NICOLAS
Jan 8, 2020, 5:22:42 AM1/8/20
to Hermes-Lite
> There is also the LRS-200-48, it have an enclosure and is cheaper.
> Is there a drawback to use it ?
The LRS-200-48 should be more noisy.
https://en.wikipedia.org/wiki/Power_factor#Power_factor_correction_(PFC)_in_non-linear_loads
Mathis Schmieder
Jan 13, 2020, 3:04:59 PM1/13/20
to Hermes-Lite
Dear Group,
I was finally able to find some time to continue work on this. Please see the updated schematics. Layout and routing is also finished so far and I was just about to order 5 prototypes at JLCPCB, but Chinese New Year got my by surprise and the boards would have been built starting on February 1st. So I didn't go through with the order just yet and will tweak it some more ;)
The resistor values for the forward/reverse detector circuit were changed and I've also reworked the fan control - theoretically, it should turn on at around 55°C and turn off again when the heat sink has cooled down to 40°C. As I'm not very good with op amps, I'd highly appreciate it if someone with more experience with them could look over what I did. Otherwise, I'll SPICE that part of of the circuit. The biasing logic and filter order has also been reversed.
Because of the unexpected delay thanks to Chinese new year, I'll also add a shunt and current sensing circuit to the PA supply and add another I2C ADC to read the PA current and heatsink temperature.
I am a bit concerned about the 3.3V supply. The HL2 schematics state that it's rated to 1.5A. Of that, the relays on the PA board draw about 200-250mA alone. Is there enough head room in the supply on the HL2, or should I put a dedicated 3.3V supply on the PA board?
Anyways, I'd highly appreciate some feedback regarding the schematic changes and board layout/routing. It's not the most aesthetically pleasing routing job I've done, but it should at least be good impedance wise.
Best 73s,
Mathis, DB9MAT
Steve Haynal
Jan 14, 2020, 2:02:53 AM1/14/20
to Hermes-Lite
Hi Mathis,
There is 1.5A of headroom on the 3.3V supply. You might consider running the relays at 12V or Vsup. The ULN2003 should support input logic at 3.3V and switch 12V on the output. There is a wider selection of 12V relays. A direct replacement is the https://www.digikey.com/products/en?keywords=ec2-12nu
I took a quick look at the schematics and layout. Some thoughts:
** You may need an attenuator on the PureSignal feedback. Right now it is 50Ohms in parallel with the main RX and will reduce RX by 3dB.
** You could go digital over i2c with the temperature/fan loop, as well as the bias setting. It would be easy to support if similar to the main HL2 board.
** What stack and dielectric are you targeting? 0.2mm between outside and inner layers and 4.5 delectric constant? I spot checked the low power RF traces and impedance seems about right. The PureSignal and LowPower RF traces are relatively long. I would flood the area around them on the outer layers with ground too, and control the impedance.
** It is possible to lower the power output of the HL2 and decrease the attenuation at the input of your PA. I'm not sure how much attenuation you want by design here. If the HL2 power is decreased, we should also decrease the Vpa on the HL2 so that we are not just burning the extra power on the HL2 PA.
** Have you given any thought to modulation the 50V power supply for Envelope Tracking and EER?
73,
Steve
kf7o
Mathis Schmieder
Jan 14, 2020, 2:47:20 AM1/14/20
to Hermes-Lite
Hi Steve,
Thanks a lot for your comments! I'll reply in line
On Tuesday, January 14, 2020 at 8:02:53 AM UTC+1, Steve Haynal wrote:
Hi Mathis,There is 1.5A of headroom on the 3.3V supply. You might consider running the relays at 12V or Vsup. The ULN2003 should support input logic at 3.3V and switch 12V on the output. There is a wider selection of 12V relays. A direct replacement is the https://www.digikey.com/products/en?keywords=ec2-12nu
I thought about that. I'll compare characteristics, but as they're both Kemet EC2 type, I guess they'll behave more or less the same. A wider available selection of 12V relays does make sense though.
I took a quick look at the schematics and layout. Some thoughts:** You may need an attenuator on the PureSignal feedback. Right now it is 50Ohms in parallel with the main RX and will reduce RX by 3dB.
Okay, how much attenuation are we talking about? I guess we would need it near the HL2 connector, not near the SMA?
** You could go digital over i2c with the temperature/fan loop, as well as the bias setting. It would be easy to support if similar to the main HL2 board.
Again, I was thinking about that already and will probably implement it. This way, we could even do PWM for the fan. I would definitely need help with implementing that in the Gateware though :)
** What stack and dielectric are you targeting? 0.2mm between outside and inner layers and 4.5 delectric constant? I spot checked the low power RF traces and impedance seems about right. The PureSignal and LowPower RF traces are relatively long. I would flood the area around them on the outer layers with ground too, and control the impedance.
I am aiming for JLCPCB's JLC7628 (https://jlcpcb.com/quote/pcbOrderFaq/PCB%20Stackup) 4 layer stackup. Dielectric constant is 4.6 with 0.2mm between outer layers and 1.065mm core. All RF signals except for low power Tx and Pure Signal have signal on top and ground on inner layer 2 (1.265mm of dielectric in between). The traces are 1.6mm wide, impedance is a *bit* high with about 60 Ohms, but 2mm wide traces would have been a bit too much. Low power Tx and Pure Signal have their ground on inner layer 1, so 0.2mm of dielectric in between. A trace width of 0.35mm is pretty much bang on 50 Ohms. I agree that they're quite long, but apart from uFL connectors and have them on coaxial cable, I don't see another way, unfortunately. In the end, it's shortwave we're talking about...
** It is possible to lower the power output of the HL2 and decrease the attenuation at the input of your PA. I'm not sure how much attenuation you want by design here. If the HL2 power is decreased, we should also decrease the Vpa on the HL2 so that we are not just burning the extra power on the HL2 PA.
Right now, I'm aiming for 6 dB of attenuation. We need 1-2W of power to the MRF101 for 100W output. Lowering the HL2 power is probably a good idea, otherwise we're just heating up everything.
Not yet, but it's quite interesting! I'll keep that in mind for a later revision though!
Again, thanks a lot for your feedback!
73s,
Mathis
in3otd
Jan 14, 2020, 3:24:59 AM1/14/20
to Hermes-Lite
Hello Mathis,
On Tuesday, January 14, 2020 at 8:47:20 AM UTC+1, Mathis Schmieder wrote:
[snip]
On Tuesday, January 14, 2020 at 8:02:53 AM UTC+1, Steve Haynal wrote:
[snip]
There is 1.5A of headroom on the 3.3V supply. You might consider running the relays at 12V or Vsup. The ULN2003 should support input logic at 3.3V and switch 12V on the output. There is a wider selection of 12V relays. A direct replacement is the https://www.digikey.com/products/en?keywords=ec2-12nuI thought about that. I'll compare characteristics, but as they're both Kemet EC2 type, I guess they'll behave more or less the same. A wider available selection of 12V relays does make sense though.
I guess Steve's point was that you could use the 12 V supply for the relais to avoid increasing the load on the H-L 3.3V supply. At 12V the relais require one fourth of the current of the 3 V models and moreover they would be connected directly to the external 12 V supply.
There may have been a reason to use 3 V relais instead of the 12 V ones on the H-L but I don't remember it right now, hi.
[snip]
I am aiming for JLCPCB's JLC7628 (https://jlcpcb.com/quote/pcbOrderFaq/PCB%20Stackup) 4 layer stackup. Dielectric constant is 4.6 with 0.2mm between outer layers and 1.065mm core. All RF signals except for low power Tx and Pure Signal have signal on top and ground on inner layer 2 (1.265mm of dielectric in between). The traces are 1.6mm wide, impedance is a *bit* high with about 60 Ohms, but 2mm wide traces would have been a bit too much. Low power Tx and Pure Signal have their ground on inner layer 1, so 0.2mm of dielectric in between. A trace width of 0.35mm is pretty much bang on 50 Ohms. I agree that they're quite long, but apart from uFL connectors and have them on coaxial cable, I don't see another way, unfortunately. In the end, it's shortwave we're talking about...
I did not yet look at the layout but I assume there is a ground pour on the outer layers; you may then be able to lower the 1.6 mm traces impedance by reducing the ground clearance between the signal traces and the surrounding ground. IIRC, this is done also on the N2ADR filter board to get traces with 50 ohm impedance.
73 de Claudio, DK1CG / IN3OTD
Mathis Schmieder
Jan 14, 2020, 3:45:11 AM1/14/20
to Hermes-Lite
On Tuesday, January 14, 2020 at 9:24:59 AM UTC+1, in3otd wrote:
Hello Mathis,On Tuesday, January 14, 2020 at 8:47:20 AM UTC+1, Mathis Schmieder wrote:[snip]On Tuesday, January 14, 2020 at 8:02:53 AM UTC+1, Steve Haynal wrote:[snip]There is 1.5A of headroom on the 3.3V supply. You might consider running the relays at 12V or Vsup. The ULN2003 should support input logic at 3.3V and switch 12V on the output. There is a wider selection of 12V relays. A direct replacement is the https://www.digikey.com/products/en?keywords=ec2-12nuI thought about that. I'll compare characteristics, but as they're both Kemet EC2 type, I guess they'll behave more or less the same. A wider available selection of 12V relays does make sense though.
I guess Steve's point was that you could use the 12 V supply for the relais to avoid increasing the load on the H-L 3.3V supply. At 12V the relais require one fourth of the current of the 3 V models and moreover they would be connected directly to the external 12 V supply.There may have been a reason to use 3 V relais instead of the 12 V ones on the H-L but I don't remember it right now, hi.
Probably because there's no 12V on the N2ADR filter board ;) For the HL2 mainboard, I don't know, but it's just one relay there, so the impact isn't quite that big.
[snip]I am aiming for JLCPCB's JLC7628 (https://jlcpcb.com/quote/pcbOrderFaq/PCB%20Stackup) 4 layer stackup. Dielectric constant is 4.6 with 0.2mm between outer layers and 1.065mm core. All RF signals except for low power Tx and Pure Signal have signal on top and ground on inner layer 2 (1.265mm of dielectric in between). The traces are 1.6mm wide, impedance is a *bit* high with about 60 Ohms, but 2mm wide traces would have been a bit too much. Low power Tx and Pure Signal have their ground on inner layer 1, so 0.2mm of dielectric in between. A trace width of 0.35mm is pretty much bang on 50 Ohms. I agree that they're quite long, but apart from uFL connectors and have them on coaxial cable, I don't see another way, unfortunately. In the end, it's shortwave we're talking about...I did not yet look at the layout but I assume there is a ground pour on the outer layers; you may then be able to lower the 1.6 mm traces impedance by reducing the ground clearance between the signal traces and the surrounding ground. IIRC, this is done also on the N2ADR filter board to get traces with 50 ohm impedance.
On the top layer, where most of the RF is, there is no ground copper pour. I'll see if that's possible/useful though.
73s,
Mathis, dB9MAT
Mathis Schmieder
Jan 14, 2020, 6:19:45 AM1/14/20
to Hermes-Lite
Dear Group,
I have updated the schematics to include PA current monitoring and bias setting via an I2C pot. The temperature is also exposed via a 4 channel I2C ADC. Now I'm thinking about how to best control the fan. The easiest way would be to use one of the unused pins of the GPIO expander to simply turn it off and on from the HL2. Is there a non-overkill method to do PWM fan control via I2C? Most parts I'm finding are YUGE and support way too many features for us. Ideas/opinions?
Thanks,
Mathis, dB9MAT
WA2EUJ
Jan 14, 2020, 6:24:26 AM1/14/20
to Hermes-Lite
Hi Mathis,
I notice on your relays that you only have a bypass cap on the control side of the coil and nothing on the power side. I think you need to add a cap to ground for each relay on the power side as well as there's a good bit of RF picked up by the coil that can cause relay chatter and erroneous switching. On my LPF design I used a 0.1uF to ground on the power side and a bead in series with the control. This seems to work OK, the earlier version that only had a cap to ground on the power side had trouble at high power.
73,
Jim WA2EUJ
WA2EUJ
Jan 14, 2020, 6:36:00 AM1/14/20
to Hermes-Lite
Many switching supplies for 48V (Meanwell EPP200-48) have a speed controlled 12V fan output that can be used to control the fan for the PA. Strategically located, a single fan can provide moving air for the power supply and PA.
Jim.
Mathis Schmieder
Jan 14, 2020, 8:08:48 AM1/14/20
to Hermes-Lite
Dear Jim,
I do have bypass caps on the power side as well! Check C43-C52 and C63. In the schematics, they are bundled together near K10. Or did I misunderstand what you proposed? Regarding a ferrite bead in series with the controls, I might add those..
Thanks & 73s,
Mathis, DB9MAT
in3otd
Jan 14, 2020, 4:13:12 PM1/14/20
to Hermes-Lite
Hello,
I took a closer look at the schematic and have a few comments/questions:
Regarding the directional coupler :
- the reactance of 10 turns on a FT50A-61 seems to be around 85 ohm at 1.8 MHz, which causes a significant mismatch at the amplifier output - a SWR of 1.8 with a 50 ohm load. Isn't this an issue in practice?
- the transformers connections appear to be "not fully right"; while this circuit "always works", the transformers phasing is important, especially for higher coupling values. This circuit
has a directivity limited by the transformers turn ratio (e.g. 20 dB when using 1 turn : 10 turns transformers) and for a 50 ohm load will provide a non-zero reflected output. The actual REV and FWD coupling values will also be slightly different in practice, due to the core losses (but this effect is usually small).
On the other hand this one
has (ideally) a perfect directivity and equal FWD/REV coupling values, even with lossy cores.
- as noted by K6JCA, the cores used need not to be the same size, in theory only the "voltage sensing" transformer needs a large core since the "current sensing" transformer will have a magnetic flux density reduced more or less proportionally to the coupling ratio. So to save some space, the current sensing transformer could be probably be done with an FT37. If the coupler circuit is changed to a "Bruene coupler", like on the N2ADR board, the voltage sensing transformer could be eliminated, replaced by a (capacitive) divider. But I didn'y check if this circuit will have reasonable component values.
- or, keeping the same circuit, it may be better to reduce the coupling by increasing the number of turns from 10 to 20. This will reduce the flux in the voltage sensing transformer and increase its inductance, reducing the loading effect on 160 m. At high frequency the performances may be degraded but it could still be ok as we need to go only up to 30 MHz. The voltage on the diodes will be lower but we could partially recover that by increasing the diodes load, which will also make the detectors more linear at low power levels.
Regarding the output filters, I saw that the inductance values in the excel table are 10 % to 20 % higher than the typical inductance calculated for the toroids and number of turns used. Some filters (40m/30m, 15m/12m/10m) seems to have a corner frequency very near the band edge when simulated using the inductance values from the table, while the response seems better when using the typical toroids inductance. Which is the correct value inductance to use? (BTW, on Mathis schematic 224 nH should be 244 nH, per Jim's table)
In the latest schematic, the MCP4561 used for setting the LDMOS bias has almost 6 V on pin 5 but the voltage there cannot be higher than Vdd (3.3 V). You may be able to use that device anyway by limiting the voltage range seen at its pins, as done for the H-Lv2 bias circuitry - there is no need to be able to go up to 6 V for biasing the gate.
WA2EUJ
Jan 14, 2020, 4:54:15 PM1/14/20
to Hermes-Lite
I forgot to mention that you should put a back EMF diode on the fan PWM.
I'll say one thing about the toroid tables, they are wrong. The constant is based on A(L100) which is the inductance of 100 turns which is probably accurate for 100 turns maybe even 25-50 turns but is inaccurate for inductors with less than 20 turns (which is most of the inductors in the design). Now, every time I wind a toroid, I measure it with a VNA and add the actual inductance to my database and I'm starting to get a good feel for the actual inductance vs. # of turns and type of core as well as the tolerance that can be expected coil-to-coil.
That might be an interesting crowd-sourced project given the proliferation of Nano-VNA's we could seriously improve inductance VS. winding accuracy.
If I get a chance, I'll plot the actual response of the filters and put it on the RFPowerTools.com website.
All that I have posted is the harmonics of the amp running through the output filters:
73,
Jim WA2EUJ
Steve Haynal
Jan 14, 2020, 11:57:48 PM1/14/20
to Hermes-Lite
Hi Mathis,
Any attenuation on the PureSignal feedback should be as close as possible to the HL2 connector. We are determining experimentally what attenuation to use on the PureSignal feedback. I think it should be sufficient to include footprints for small pi or t attenuator. The IO boards can support either. See the page below for details and links to pi and t attenuators.
https://github.com/softerhardware/Hermes-Lite2/tree/master/hardware/companions/psfeedback
An alternative (or addition) to a back EMF diode on the fan is to make the low current control edge less sharp with a low pass filter as described in this app note:
I had problems with noise and the HL2 fan. I reduced the PWM frequency, but will add the low pass filter in any future revs of the IO boards. There are no spare FPGA outputs on the 2x20 N2ADR filter board connector you are using. You may want to consider grabbing a few output signals from the front DB1 connector. I am just testing the gateware with fan control. It would be easy to use the same PWM output or add another if you like. Fan control from the powe rsupply also sound like an interesting option.
73,
Steve
kf7o
dick_...@hotmail.com
Jan 15, 2020, 1:55:12 AM1/15/20
to Hermes-Lite
Claudio
The second circuit below is not quite right. It results in a phase shift as you indicate, but is not the same as the majority of the circuits used and will end up requiring a lead swap for fwd and rev with most software. I know because I did a directional coupler with that configuration.
Perhaps you would like to look at the following paper:
Heikki Ahola
Jan 15, 2020, 2:10:16 AM1/15/20
to Hermes-Lite
Hi group,
It is also my experience that using the AL100 value as such for iron powder toroids gives erraneous inductance values, systematically too low, as I usually need to remove 1 - 2 turns after measuring the coil. The "correct" values in my case are based on measurements with a capacitance bridge which is uncalibrated, unfortunately. The filters, on the other hand, built with these measured toroids, seem to behave as predicted by e.g. Elsie. Also, what is often neglected is the winding shape, i.e. how the turns are distributed along the toroid perimeter. Therefore measuring all inductances is quite important unless we have measurement -based tables for each and every type of toroidal core involved, including nturns, winding shape and wire diameter, at least.
73 de Heikki (OH2LZI)
dick_...@hotmail.com
Jan 15, 2020, 2:23:37 AM1/15/20
to Hermes-Lite
Hi Steve
I was working on a slightly different circuit today for the HL2 side of the Pure Signal injection. It is just a spread sheet to do the math to establish the attenuation and resistor values for a pad and variable adjustment for fine tuning. I have attached the spreadsheet with my Initial solution with the green highlighting. I think you can visualize the circuit from the spread sheet . It is a 6dB pi pad with a 1K trimpot and a 470 ohm resistor that would go to the header for RF1. I would like to use a uFL connector for the input and orientate the pcb over the filter board relays to keep the signal away from the RF power stages and relay.
The circuit [untested] would give about a 10dB adjustable range, properly terminate the 50 cable from the directional coupler and provide about 30 dB of additional attenuation. If the directional coupler provides 20dB of attenuation plus a 10dB pad, this would amount to 60 dB total +/-5. Anything more could be accomplished with SMA attenuators. If 60 dB is too much the pi pads at both ends could be reduced to a lower attenuation.
the uFL to SMA cables are relatively inexpensive and if you buy 4 they are only $0.99 ea.
I was planning to make a system diagram later. Just finished the spreadsheet.
Dick
Steve Haynal
Jan 18, 2020, 6:45:47 PM1/18/20
to Hermes-Lite
Hi Dick,
Thanks for looking into this. I've been worried about this and your R&D will definitely help.
73,
Steve
kf7o
Don Solberg
Jan 19, 2020, 9:10:57 AM1/19/20
to Hermes-Lite
Maybe I am missing something but I don't see the benefit of putting the attenuator on the PCB. I use an external step attenuator, which allowed me to easily vary the amount of attenuation depending on the power level I was running. Since I always run with my amplifier on I don't have to touch the settings on the attenuator. When I increase the power output in the future it will be very simple to adjust the attenuation.
73,
Don
K9AQ
dick_...@hotmail.com
Jan 19, 2020, 4:38:19 PM1/19/20
to Hermes-Lite
Hi Steve
I have done another pass at the attenuator / isolator which is attached. From some of the discussion I think the 6dB version will be too much for the stand alone HL2 and most directional couplers, so the latest approach is to use the "2dB" values. I also think the pot is not necessary as a 5K pot across the termination of the DC will provide adequate adjustment. I plan to build up a low power DC similar to the one on my DC page, with a 5k pot on the output.
Don K9AQ. The attenuator is actually an isolation circuit to keep the Pure Signal circuitry from loading the receiver input during receive. It would not be necessary if the Tx and Rx were isolated as in the original TAPR Hermes or if the HL2 is configured the same way. Depending upon your point of view, isolation comes with attenuation or visa versa.. Therefore the total attenuation needs to be shared between the HL2 and the signal tap. There is also a need for some signal switching as well - See:
Using an external step attenuator is fine, once you know what levels are expected and needed at both ends of the cable. Adding amplification will probably not help Pure Signal if the isolation is too large in the first place
Dick K9IVB
Dick
Don Solberg
Jan 19, 2020, 7:57:44 PM1/19/20
to Hermes-Lite
Dick,
I bought a TAPR TR-Plus T/R switch before I understood how the receive ant (RF3) is connected in parallel with the main ant feed to the ADC. This is different than the original Hermes board. I feed the output of my step attenuator directly into RF3. I have PureSignal working very well with the HL2 barefoot and more importantly with my external amplifier.
How do you plan on using the TR-Plus?
Don
K9AQ
Christian Veith
Jan 24, 2020, 6:39:06 PM1/24/20
to Hermes-Lite
Hi Mathis,
Am Mittwoch, 1. Januar 2020 14:17:41 UTC+1 schrieb Mathis Schmieder:
thanks for your work on that project.
What i would like on the pa board are switchable outputs for transverters with switching of the low power output and the rx signal and dedicated ptt lines per transverter.
Maybe switched power lines to the transverters would be cool to reduce power consumption when using other bands.
The question is how many transverters should be possible. I don't have an answer for that. but having 50 / 70 MHz or 144/430 would be cool.
Best regards
Chris (DL5CV)
Am Mittwoch, 1. Januar 2020 14:17:41 UTC+1 schrieb Mathis Schmieder:
Dear group,I've been working on a companion board that features an MRF-101 100W power amplifier and a 6 band low pass filter bank. It's heavily based on both Jim WA2EUJ's MRF101 EVB that won NXP's homebrew challenge and James N2ADR's filter board that you probably all know. For now it's only schematics but I'm planning on laying out the board soon. I've uploaded the design files to Github: https://github.com/mathisschmieder/HL2-MRF101I'm sure the design contains one or the other brain fart and I'd therefore invite all of you to do a sanity check. Generally, I'm very interested in your opinions on this board! Direct link to the schematics is here.Looking forward to your input and wishing you all a happy new year,Mathis, DB9MAT
Mathis Schmieder
Jan 27, 2020, 4:06:58 AM1/27/20
to Hermes-Lite
Dear Group,
thanks a lot for all your input.
First of all, Chris, what you are describing is a whole different project. While it would definitely be interesting and nice to have, I'm not going to integrate that on the 100W PA board. If your main goal is using transverters, you absolutely don't need a 100W power amplifier - all of the transverters I know need only a couple of dBm. I could see myself designing something like that in the N2ADR filter board form factor in the future.
As for all the other suggestions, this is my current todo list for the first version of this project:
- Remove low power Tx and Pure Signal sampling traces and replace them with either SMA or uFL connectors close to the HL2 pin connector. I'm a bit afraid of overtalk from the LPF bank onto the traces. Short coax jumpers to the front panel should have much better shielding
- Add PI attenuator pad to Pure Signal sampling connector
- Add ferrite beads to the "second half" of relays
- Read up on directional couplers and possibly rework fwd/rev power detection circuit.
- Add header to connect to DB1 on the HL2 board and grab fan PWM signal from there
- Add either back EMF diode or low pass filter to fan control
JLCPCB will re-start production on the 2nd of February and I hope to have a first revision ready by then.
Looking forward to your input,
73s Mathis DB9MAT
Mathis Schmieder
Jan 27, 2020, 4:08:24 AM1/27/20
to Hermes-Lite
Forgot to add rework of the digital pot to the todo list. This will of course also happen.
Mathis Schmieder
Jan 27, 2020, 10:44:45 AM1/27/20
to Hermes-Lite
Dear group,
I have worked off the todo list with the exception of the directional coupler. @Steve, I have used Pin 4 on DB1 for the fan control and copied the circuit off your end plate with the addition of a low pass filter and back EMF diode.
The digipot should now never see more than 3.3V and the bias voltage can be set between 1 and 3.3V, which is perfectly fine for the MRF101.
Regarding the directional coupler, currently I'm leaning towards keeping the circuit as it is and trying it out, maybe playing with different core materials / coupling factors. If anybody has a precise suggestion what I should change, I'd be happy to incorporate that, but currently I'm a bit lost as there are countless different designs out there and anyone says his is the best. :)
Best 73s,
Mathis, DB9MAT
in3otd
Jan 27, 2020, 12:41:01 PM1/27/20
to Hermes-Lite
Hello Mathis,
I took a quick look at the bias circuit and something doesn't look right to me; the MRF101 gate bias seems to be connected directly to the zener+diode circuit.
Regarding the directional coupler, probably in practice there is little difference between the various options - if there is space on the board, it may be good to add some pads to be able implement a "Bruene coupler", like on the N2ADR filter board, so one can easily experiment with that option too.
73 de Claudio, DK1CG / IN3OTD
in3otd
Jan 27, 2020, 4:39:54 PM1/27/20
to Hermes-Lite
Regarding the bias, a circuit like this should be ok and quite similar to the original one, only the maximum bias voltage is reduced but it's still almost 3.3 V, hopefully that's high enough:
Mathis Schmieder
Jan 30, 2020, 3:30:05 AM1/30/20
to Hermes-Lite
Thanks a lot! To be honest, I was completely ignoring the Zener-Diode D4 that's clamping down the voltage to 5.1V. The circuit that you suggested makes total sense and I'll use that. :)
Mathis Schmieder
Jan 30, 2020, 1:38:48 PM1/30/20
to Hermes-Lite
Dear Group,
Because JLCPCB won't restart production until at least the 10th of February, I have now ordered 3 boards locally at aisler.net. They have a lead time of 8 days, so I'll probably have the boards early in the week after next. Quite exciting! :)
Best 73s,
Mathis, DB9MAT
Steve Haynal
Jan 31, 2020, 10:36:41 PM1/31/20
to Hermes-Lite
Hi Mathis,
This looks fine to me. The original circuit came from Taka. It has been working in the IO testing. The low pass filter will be nice.
73,
Steve
kf7o
Mathis Schmieder
Feb 4, 2020, 10:19:00 AM2/4/20
to Hermes-Lite
Hi Steve, Group,
While waiting for the boards to arrive I tried to read into the Gateware code but I have to admit that, right now, I'm in WAY over my head. I'm pretty sure I need help in adjusting the Gateware to support this PA companion.
The following devices are present on the companion's I2C bus:
- MCP23008 GPIO Expander at address 0x20 - same as on the N2ADR board. This should work out of the box.
- MCP4561 Digipot at address 0x2E - similar to the HL2 main board. I'm pretty sure that we can talk to this one in the same way as we're talking to the MCP4662 on the HL2 main board. It's on the same I2C bus as the internal one and the way it's talked to with the HL2Setup program seems easy enough. No changes in Gateware necessary, AFAICT.
- MAX11613 Slow ADC at I2C address 0x34 - same IC as on the HL2 mainboard but on a different I2C bus. The data has to be read in Gateware and sent via a UDP packet. This is the one I definitely need help with. The temperature sensor is connected to AIN0 and the PA current sense voltage is connected to AIN1. AIN2&3 are not connected.
The temperature sensor is a LM35DT with an output voltage of 10mV/°C - so for example, 40°C correspond to 400mV. We need to figure out a way how to factor in this temperature for the fan control. Initially, I thought the fan should start running full speed at 55°C and stop running when the heat sink temperature is below 40°C again. It's probably not the most elegant solution, but I'm open to suggestions.
Anyway, it would be awesome if someone fluent in Verilog (I guess it's Verilog and not VHDL?) could implement the Slow ADC sensor!
Best 73s,
Mathis, DB9MAT
Steve Haynal
Feb 5, 2020, 12:36:41 AM2/5/20
to Hermes-Lite
Hi Mathis,
The i2c buses are combined internally even though they are on different pins. Is it possible to change the MAX11613 address? Send or lend me one of the early builds and I will make the Verilog changes.
Since there is just one sensor, I prefer to hard code the limits in the Verilog in the native units of your temperature sensor. This is the least work and thus resource usage. For the current fan, there are 3 speeds as describe in an earlier post.
73,
Steve
kf7o
Mathis Schmieder
Feb 5, 2020, 3:47:55 AM2/5/20
to Hermes-Lite
Hi Steve,
That's definitely a problem. As far as I can tell, it's not possible to change the MAX11613 slave address, neither through hardware nor software. I always assumed that the i2c busses were separate, it would be good to have known that before ordering first boards ;) I'll see if I can find a differnt 2 or 4 channel 12 bit ADC with similar characteristics but differnt address.
That's definitely a problem. As far as I can tell, it's not possible to change the MAX11613 slave address, neither through hardware nor software. I always assumed that the i2c busses were separate, it would be good to have known that before ordering first boards ;) I'll see if I can find a differnt 2 or 4 channel 12 bit ADC with similar characteristics but differnt address.
Sure, I'll gladly send a board to you once they're here and I confirmed that they at least do something. At that time, I'll privately send you an email to discuss addresses etc.
I agree that it's enough to hard code the limits in Verilog. In hindsight, I'm not sure if it was clever to connect the fan on "my" companion board to the same GPIO that you allotted to the case fan. What do you think?
73s,
Mathis DB9MAT
Mathis Schmieder
Feb 5, 2020, 4:12:20 AM2/5/20
to Hermes-Lite
I think I found a solution: The MAX11644 seems quite similar to the MAX11613, has 2 inputs (IN3&4 are unused on the PA companion) but is otherwise pin compatible to the 11613. And it comes with a different I2C address: 0x36 :)
Another thing that's unclear to me: In the HL2Setup program, you are converting the ADC values back to amps by the following formula:
| hermes_pa_current = (3.26 * (hermes_pa_current/4096.0))/50.0/0.04; |
Similarly, the voltage is converted by (3.26 * (hermes_temp/4096))etc. - Where are the 3.26 coming from? As far as I can tell, the reference voltage for the MAX11613 is 2.048V - shouldn't the 3.26 actually be 2.048? What am I missing?
73s,
Mathis DB9MAT
Mathis Schmieder
Feb 5, 2020, 4:22:15 AM2/5/20
to Hermes-Lite
Obviously the MAX11644 is the 5V part, I meant the MAX11645. The other question still stands...
in3otd
Feb 5, 2020, 3:28:17 PM2/5/20
to Hermes-Lite
Hello,
the MAX11613 by default uses Vdd as reference; to use the internal 2.048 V reference a register would need to be programmed.
I think that 3.26 is used instead of 3.3 because that's the typical voltage of the 3.3 V supply on the H-Lv2 (its nominal value would be 3.28 V, from the switching regulator resistors used).
73 de Claudio, DK1CG / IN3OTD
Mathis Schmieder
Feb 5, 2020, 3:43:10 PM2/5/20
to Hermes-Lite
Hi Claudio,
Thanks for clarifying that! Clearly, properly reading the data sheet pays off :) Totally missed that it can use VDD as Vref. The 3.26 now totally make sense.
73s,
Mathis, DB9MAT
Mathis Schmieder
Feb 7, 2020, 11:46:18 AM2/7/20
to Hermes-Lite
Dear Group,
Good news! Today, I received the first three prototype PCBs and already assembled one. Everything went well and so far I'm only missing two capacitors for the 160m filter and the 2-channel ADC. God, do I hate soldering enamelled wire...
I could already verify the board in receive mode and filter switching is working beautifully. For testing transmitting, I'm still waiting for the 50V power supply to turn up. I'll probably use a bench power supply at work on Monday and I'll need to find a way to talk to the I2C digipot on the board. Worst case, I'll have to use a bus pirate, so no real problem here.
The companion is connected to the HL2 using stackable pin headers and sits 22mm above the main board. In the next hardware revision, I'll give the toroids a little more space, but it should work fine as it is right now. I'll also add a fuse for the 50V line.
As soon as I verify transmit is working, I'll order a second set of parts (including the new ADC) and send a board to Steve for him to implement the ADC into the gateware.
Fingers crossed, but so far it's looking good! :)
Best 73s,
Mathis, DB9MAT
PS: Did I mention that I HATE soldering enamelled wire?
Alan Hopper
Feb 7, 2020, 11:57:35 AM2/7/20
to Hermes-Lite
Hi Mathis,
looking very good, If you want anything custom in SparkSDR to help get this going please ask. I assume the frequency bands of the filters are the same as the N2ADR board, if not let me know and I'll generate a new smart filter file.
73 Alan M0NNB
ps do you have a view on enameled wire?
Mathis Schmieder
Feb 7, 2020, 12:32:15 PM2/7/20
to Hermes-Lite
Hi Alan,
Bit 7 is a HPF just like on the N2ADR board. It can stay enabled during Tx. For the PA bias setting I have a similar digipot on my board as on the HL2 mainboard. I'll check the datasheet of the MCP4561 and tell you what exactly has to be sent, but I expect it to be very similar to the onboard MCP4662 on the HL2 board. The 4561 is a single pot, as compared to the dual rheostat in the 4662. So a third slider to set the MRF101 PA bias would be awesome!
That would be great! The filters are actually a bit different to the N2ADR board. The following bits have to be set:
Bands Bits 7 6 5 4 3 2 1 015-10 1 0 0 0 0 0 0 120-17 1 0 0 0 0 0 1 040-30 1 0 0 0 0 1 0 060 1 0 0 0 1 0 0 080 1 0 0 1 0 0 0 0160 0 0 1 0 0 0 0 0Bit 7 is a HPF just like on the N2ADR board. It can stay enabled during Tx. For the PA bias setting I have a similar digipot on my board as on the HL2 mainboard. I'll check the datasheet of the MCP4561 and tell you what exactly has to be sent, but I expect it to be very similar to the onboard MCP4662 on the HL2 board. The 4561 is a single pot, as compared to the dual rheostat in the 4662. So a third slider to set the MRF101 PA bias would be awesome!
For now, we can't read the MRF101 bias current, because I'm still waiting for the 2-channel ADC and the necessary changes in the Gateware. But for now, measuring the current externally should be fine.
Thanks again,
Mathis, DB9MAT
Alan Hopper
Feb 7, 2020, 3:43:29 PM2/7/20
to Hermes-Lite
Hi Mathis,
I'll try and sort something out either tomorrow or Sunday, what os are you using (saves me a bit of effort to just build 1 version)?
73 Alan M0NNB
in3otd
Feb 8, 2020, 2:31:34 AM2/8/20
to Hermes-Lite
Looks great!
for the bias, I'd just temporarily disconnect the digipot and use a normal trimpot - but Alan may be quicker at adding the digipot support in Spark :) .
By the way, I also recently enjoyed winding toroids and soldering enameled wire, also in preparation for building a PA board (maybe, one day...):
but not as much as when I used some sort of high temperature enameled wire, where it was almost impossible to scratch away the insulation properly @%$&#!
73 de Claudio, DK1CG / IN3OTD
Marc OLANIE
Feb 8, 2020, 3:24:01 AM2/8/20
to in3otd, Hermes-Lite
Hi Claudio et All
Nice familly picture :- )
« it was almost impossible to scratch away the insulation properly @%$&#! »
Dremel is good for you :- D (and for us all) I’ll build a statue of the guy who’ll find a quick and efficient trick to do that.
As blocking windings for low inductances values is sometime difficult (21, 25, 32 MHz for eg. ), I used to make a « two wires in hand » winding, just to have a better mechanical consistency of the inductance. Without this precaution, the value of the inductance could strongly vary.
My 2 cts
Marc f6itu
Mathis Schmieder
Feb 8, 2020, 3:55:15 AM2/8/20
to Hermes-Lite
Hi Alan,
Store value to non-volatile EEPROM:
I took this code from HL2Setup. hw_command[3] puzzles me a bit, setting the non-volatile wiper is done by writing to address 0x02 in both the MCP4561 and MCP4662, but the code says 0x20. Maybe there's something going on in the gateware that translates the UDP data to I2C? Anyway, it seems to work with the MCP4662 as it is, so it should work with the 4561 as well. :) The only difference is the I2C address: 0x2E instead of 0x2C.
Perfect! I'm running Windows 10 (and Mac OS, but there's no Mac version, right?). Getting a Linux box would't be a problem though, if that's much easier for you. I checked the MCP4561 data sheet, and setting the digipot is similar to the MCP4661. The following bytes have to be sent:
Set value to volatile RAM:
hw_command[0] = 0x3D; // ADDRhw_command[1] = 0x06; // I2C2 cookie, must be 0x06 to writehw_command[2] = 0xAE; // I2C2 stop at end + target chip addresshw_command[3] = 0x00; // I2C2 control: MCP4561 Command Byte: Address 0, write datahw_command[4] = (unsigned char)code; // I2C2 data: MCP4561 Data Bytehw_command[0] = 0x3D; // ADDRhw_command[1] = 0x06; // I2C2 cookie, must be 0x06 to writehw_command[2] = 0xAE; // I2C2 stop at end + target chip addresshw_command[3] = 0x20; // I2C2 control: MCP4561 Command Byte: Address 3, write datahw_command[4] = (unsigned char)code; // I2C2 data: MCP4561 Data ByteI took this code from HL2Setup. hw_command[3] puzzles me a bit, setting the non-volatile wiper is done by writing to address 0x02 in both the MCP4561 and MCP4662, but the code says 0x20. Maybe there's something going on in the gateware that translates the UDP data to I2C? Anyway, it seems to work with the MCP4662 as it is, so it should work with the 4561 as well. :) The only difference is the I2C address: 0x2E instead of 0x2C.
If this needs some clarification, please let me know!
Thanks again,
Mathis, DB9MAT
Alan Hopper
Feb 8, 2020, 8:38:08 AM2/8/20
to Hermes-Lite
Hi Mathis,
give this a go http://www.ihopper.org/radio/sparksdr2_0_1_0beta8_win64.zip it only has the bias, no filters yet. You might want to check the slider goes the correct way, I remember something odd in the early days of hl2 bias where the direction reversed. You are the first person to ask about spark on mac, this should be fairly simple so if there is interest I'll add it to the list.
73 Alan M0NNB
Karl Heinz Kremer
Feb 8, 2020, 9:16:04 AM2/8/20
to Hermes-Lite
I use a Mac and some Rasperry Pi type systems, so having a native Mac version would allow me to give it a try.
Thanks,
Karl Heinz - K5KHK
Dan Porter
Feb 8, 2020, 9:40:54 AM2/8/20
to Alan Hopper, Hermes-Lite
I would be interested in a Mac version. I’m currently running in a Windows 10 VM on my iMac.
73,
Dan AI2M
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Steve Haynal
Feb 8, 2020, 2:10:16 PM2/8/20
to Hermes-Lite
Hi Mathis,
The pictures look great! Thanks for all your work!
Regarding the merged I2C buses, I can add something to the gateware at very low cost to select which I2C bus to send to, so we can support two MAX11613 on different busses if that is required and the easiest for you. My biggest request is just to finalize on the I2C landscape before proliferating many boards so that the gateware and software has a single standard interface.
I'm okay with the fan using the same output as the case fan. One other thought is that the 8th bit of the I2C band selection output (only 7 are used currently?) can be used to turn a fan on or off, no PWM.
I look forward to a beta board. What power supply do you recommend? I actually have no antenna or tuner that will support 100W. Will it be possible to use this amp at lower power, for example 20W? Also, if you want to send the sample board via way of Alan first, that is fine with me. He can make sure everything works with SparkSDR. I'm also willing to send the sample to Jim (or other software developers) if they are interested in testing and adding support to their SDR software. There are some funds in the R&D and repair pool which can be used for this.
73,
Steve
kf7o
Hi Steve,
That's definitely a problem. As far as I can tell, it's not possible to change the MAX11613 slave address, neither through hardware nor software. I always assumed that the i2c busses were separate, it would be good to have known that before ordering first boards ;) I'll see if I can find a differnt 2 or 4 channel 12 bit ADC with similar characteristics but differnt address.
That's definitely a problem. As far as I can tell, it's not possible to change the MAX11613 slave address, neither through hardware nor software. I always assumed that the i2c busses were separate, it would be good to have known that before ordering first boards ;) I'll see if I can find a differnt 2 or 4 channel 12 bit ADC with similar characteristics but differnt address.
Sure, I'll gladly send a board to you once they're here and I confirmed that they at least do something. At that time, I'll privately send you an email to discuss addresses etc.
I agree that it's enough to hard code the limits in Verilog. In hindsight, I'm not sure if it was clever to connect the fan on "my" companion board to the same GPIO that you allotted to the case fan. What do you think?
73s,
Mathis DB9MAT
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Mathis Schmieder
Feb 8, 2020, 4:11:46 PM2/8/20
to Hermes-Lite
Hi Steve,
Thanks for the kind words! It sure is fun :)
I'm perfectly fine with using the MAX11645. It has the same footprint and pinout as the 11613 with the exception that pins 3 and 4 (AIN2 and 3) are internally not connected. Well, pin 4 can be used as reference input, but that's similar to the 11613. So it's a simple component swap without any necessary rework. I only need two additional ADC channels, so from my point of view the I2C landscape is fixed and won't change in further revisions.
Let's keep the fan PWM connected as it is. You're right that one bit of the GPIO extender is still unused, there is space on the board for an additional fan connector. I might add that in a future revision - a small on/off only fan might be useful and even if it won't be used, it will not hurt to have the possibility of connecting one.
Regarding a power supply, I would redirect you to Jim's page on that matter: https://sites.google.com/site/rfpowertools/home/power-supplies You can either use a Meanwell EPP200-48 AC/DC converter or one of the cheap Chinese "1200W" DC/DC step-up converters. For 100W, the MRF101 needs a maximum of 4A at 50VDC - if you're only planning on running it with 20W you probably need quite a bit less current. As soon as I have a heat sink drilled and tapped, I'll play around with Alan's beta SparkSDR version. I'm pretty confident that I'll be able to get the bias dialled in one way or the other to test the board before I ship it to you. I'll also figure out how much drive is necessary for 20W output so that you don't damage your equipment.
The beta board should go to you first, in my opinion, as support for the additional ADC in the Gateware is necessary before it can be properly integrated into other SDR programs. If you keep it afterwards or send it on to other developers is totally up to you. I do have two spare boards of the current revision that I can build up, but I'd probably like to keep one for myself. :) That being said, PCB production in China should re-start soon and we'll be able to get our hands on more boards for a bit less cost again. I'd be happy to build a couple of boards for parts price when we hit a somewhat stable revision - although I probably won't wind the toroids for you all. ;D
Anyways, I'll have to see if I manage to find some play time tomorrow or if I have to do it on Monday during procrastination hour at work... ;)
Best 73s,
Mathis DB9MAT
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Mathis Schmieder
Feb 9, 2020, 5:41:26 AM2/9/20
to Hermes-Lite
Hi Alan,
I gave the version a go and so far was not successful. The slider doesn't seem to change anything. However, the behaviour of the two HL2 sliders changed. Whenever I move them, PTT goes off. That didn't happen before...
I'll try to setup some kind of I2C "sniffer" using an Arduino, if I can find one :)
73s,
Mathis DB9MAT
Mathis Schmieder
Feb 9, 2020, 7:34:10 AM2/9/20
to Hermes-Lite
Dear Group,
Good news! I was able to talk to the digipot using an Arduino and already saw 40-50W output power with quite sub-optimal cooling and only 30V supply. That was with only 80% drive. I'll attach a bigger heat sink and try it with 50V tomorrow, but I'm very optimistic :)
Sorry for the messy desk. :)
73s,
Mathis DB9MAT
Alan Hopper
Feb 9, 2020, 9:28:58 AM2/9/20
to Hermes-Lite
Hi Mathis,
great progress. I've overwritten the file I posted yesterday with a new one. I think the current setting had been broken for a couple of beta releases, the code now looks at the ptt signal from the radio, when sending the bias messages I use the ack option which returns packets without the ptt data hence the ptt being cancelled.
73 Alan M0NNB
Mathis Schmieder
Feb 9, 2020, 9:47:29 AM2/9/20
to Hermes-Lite
Bingo, working fine now! :) Both HL2 bias setting and MRF101 are fine and the sliders are in the correct direction!
Thanks a lot! :)
Alan Hopper
Feb 9, 2020, 10:26:29 AM2/9/20
to Hermes-Lite
Great,
I'll sort the filters out this week and ponder the temp and current stuff. I use the same table based approach for the fwd/rev power calibration as Quisk so once that is sorted it should drop in to both programs. I'm doing some work to give the drive more range by reduce the iq when the hl2 control runs out of range/resolution, I guess a maximum limit on drive might be useful with your amp, I was planning this on a per band basis anyway.
73 Alan M0NNB
Mathis Schmieder
Feb 9, 2020, 10:29:36 AM2/9/20
to Hermes-Lite
By the way, the filter bits I sent you were wrong. The correct ones are like this:
Bands Bits 7 6 5 4 3 2 1 015-10 x 1 x 0 0 0 0 120-17 x 1 x 0 0 0 1 040-30 x 1 x 0 0 1 0 060 x 1 x 0 1 0 0 080 x 1 x 1 0 0 0 0160 x 0 x 0 0 0 0 0Bits 7 and 5 are not used. I found the filter files in SparkSDR and will try to generate one for this companion. I'll share it with the group, of course.
73s
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