Re: boards and kits and stuff
Bill Is there a. Link to sch etc for this little board.? I don't have any issues with my build and a 6inch cable but then again, not checked the? higher bands. Glenn?
'72 ISUZU BELLETT SPORT Sent from my Samsung Galaxy S21 FE Smartphone.
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Did you get a chance to look at the spectrum?
That seems like a lot of power for BS170s!
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73 Greg KF5N
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Re: Oscillations on high bands
Testing my 20W PA with -10dB in verses? 0dB in I see very little change in gain on lower bands 160-7, some gain on 10-17 and significant (3dB) gain on 28-50 Mhz.?
Max 0dB in is 160-80m is 12W,? 30-20M 9W,? and 10-6M 5W.?
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Tim?
W4YN
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to avoid misunderstandings: 3.3V are only on pin46 with teensy in! Teensy produce this 3.3V by himself! we have ?different rails with 3.3V!
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if there is no 3.3V on Pin46, please check for short (without teensy) pin46 to ground!?
if there is a short you will destroy the (next) teensy if you (re)placed him!
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I was just browsing their website, and I noted that Hans has finally released beta SSB software for the QMX. Downloaded it, ran it...holy crap, it works!
SSB is created by doing magic with the IQ signals and simultaneously amplitude modulating the power feed to
the *digital* PA - which is four tiny BS170 MOSFETs in parallel-push-pull delivering nominal 5W.
The IQ calibration is done via the serial interface terminal menus. You tell it to start, it prompts you to connect a dummy load - and it just does the whole thing UNATTENDED. All bands. Takes a while, at least a half hour.
It supports CESSB, predistortion, compression, a transmit equalizer, and something called "Mic noise cancellation".
This is unique: Hans found that his CPU's ADCs were noisy. There were noise spikes every 500Hz. So what he does is
he monitors an unused ADC channel, and uses the noise in that to cancel the noise in the main ADC mike channel. Wow.
Unfortunately, the software is both closed source and encrypted.
I've interfaced it with my Tiny Linear project, and am seeing about 50W out.
- Jerry, KF6VB
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I sent out five of those new display driver boards about a week ago and only saw posted that Terrance got his working as was able to use a 3-foot long display cable without display-T41 errors/lockups. ?Anyone else built it yet? ?I know i didnt publish an assembly manual before i headed out of the country but the thing is pretty simple and i did send out a note re how to make it work on 5v or 3.3v. ?
Anyone else? ? I think its a winner but would like to know so i can get parts and boards ordered to send these out before Hamvention
Dr.?William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ ? Owner - Operator Big Signal Ranch ¨C K9ZC Staunton, Illinois ? Owner ¨C Operator Villa Grand Piton - J68HZ Soufriere, St. Lucia W.I. Rent it: www.VillaGrandPiton.com
email:??bill@... ?
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If no voltage on pin46 then the teensy socket or teensy itself is bad. ?
Dr.?William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ ? Owner - Operator Big Signal Ranch ¨C K9ZC Staunton, Illinois ? Owner ¨C Operator Villa Grand Piton - J68HZ Soufriere, St. Lucia W.I. Rent it: www.VillaGrandPiton.com
email:??bill@... ?
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On Mar 30, 2025, at 12:47?PM, Tom Schulte via groups.io <tomschulte9@...> wrote:
? Thanks for the advice. Here's what I have done so far.
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1. Replaced the LM117
2. J5- 3v and 5V on their pins
3. 5v on TP1
4. 3.3v on TP2
5. 12v on Fan port
6. Replace the pin connector for the teensy
7. No voltage? on? pin 46?
8.? 5v on pin 48
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Will keep on looking for the problem.
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Tom
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D2 and D3 are illuminated? ? If so the power rails are working. ?
Dr.?William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ ? Owner - Operator Big Signal Ranch ¨C K9ZC Staunton, Illinois ? Owner ¨C Operator Villa Grand Piton - J68HZ Soufriere, St. Lucia W.I. Rent it: www.VillaGrandPiton.com
email:??bill@... ?
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On Mar 30, 2025, at 12:47?PM, Tom Schulte via groups.io <tomschulte9@...> wrote:
? Thanks for the advice. Here's what I have done so far.
?
1. Replaced the LM117
2. J5- 3v and 5V on their pins
3. 5v on TP1
4. 3.3v on TP2
5. 12v on Fan port
6. Replace the pin connector for the teensy
7. No voltage? on? pin 46?
8.? 5v on pin 48
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Will keep on looking for the problem.
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Tom
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Thanks for the advice. Here's what I have done so far.
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1. Replaced the LM117
2. J5- 3v and 5V on their pins
3. 5v on TP1
4. 3.3v on TP2
5. 12v on Fan port
6. Replace the pin connector for the teensy
7. No voltage? on? pin 46?
8.? 5v on pin 48
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Will keep on looking for the problem.
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Tom
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1) I would take out the teensy (socketed? and possible?) and would check the TP?s like Oliver
2) if it?s ok 4 possibilities
a) Teensy is defekt
b) check Teensy Pin 46 (without Teensy) is there a short? Teensy is only able to deliver 250mA on this pin.
c) a solder bride? look for Connector J5 (disconnect cable, once I had a short)
d) one of the 3.3V consumer has a short. Please disconnect all cables (display, matrix, etc.....)
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check the poor mainboard and connect without teensy the cables 1by1 and check the voltages! special on 3.3V rail!
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I hope you are successful
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Re: Oscillations on high bands
Here's the gain of my K9HZ 20W PA:
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If we calculate the gap between the feedback amplitude and the amplifier gain, we can quantify how much margin we have before the radio begins to oscillate. It's a noisy measurement because of my NanoVNA's noise floor, but we have at least 17dB of margin.
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If I upgrade my radio to include a 100W amplifier (7dB increase in gain), this reduces the margin to at least 10dB.
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I had a Teensy blow when on power up because a the LM1117 failed. I replace the LM1117 with MP2307 buck converter module. The LM1117 had the fan and heatsink on it but its current rating is inadequate.
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Re: Oscillations on high bands
Good detective work. ? That should do it. ?
Dr.?William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ ? Owner - Operator Big Signal Ranch ¨C K9ZC Staunton, Illinois ? Owner ¨C Operator Villa Grand Piton - J68HZ Soufriere, St. Lucia W.I. Rent it: www.VillaGrandPiton.com
email:??bill@... ?
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On Mar 30, 2025, at 6:53?AM, Oliver KI3P via groups.io <oliver@...> wrote:
? I discovered that U8 (an RF switch) was not working on my LPF board. It provided very little isolation. I measured this by removing the LPF control board from my radio and testing it a NanoVNA and the LPF board testing sketch. I removed the TR carrier board, connected the transmit and receive lines together with a short piece of wire, and measured the transmission between J23 (the output of the LPF) and J18 (one of the BPF inputs) as shown in this diagram:
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Here is the measured transmission between these points before and after I replaced U8:
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After I replaced U8 I got very low feedback between the output and the input of the 20W amplifier, as shown below. I will reassemble my board now and confirm that this remains the same when running the latest software.
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Re: Oscillations on high bands
I have now confirmed that, after I replaced U8, the latest version of the code (Ver66-9) on does not suffer from oscillations on any band with my V12 radio.
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Also don't forget you have to slice the trace on the Teensy to disconnect the USB power.
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73 Greg KF5N
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Do you know how your Teensy got blown? That shouldn't happen.
Before placing your Teensy on the board, power it up and check that the DC voltages are correct. The schematic is here:
Check the following: - TP1 is +5V
- TP2 is +3.3V
- Pin 48 of the Teensy is +5V
- Pin 1 of J2 (Fan connector) is +12V
How much current does your board draw without the Teensy or fan in place? It should be pretty low -- maybe a few 10's of mA for U5 and U6.
On Saturday, March 29th, 2025 at 4:56 PM, Tom Schulte via groups.io <tomschulte9@...> wrote:
? I have a major problem with the main board. I built it with the reverse power protection. When I first built it I had 3.3vand5v at the test points. Now when I added the teensy and audio hat and test it I get I2C devices not found.? Also I have 1.35 amps and 14 watts per? the power supply meters. No longer have 3.3 v and the LM117 is very very hot to the touch. I? blow one teensy replaced with new one and resoldered all pins still no luck. Can someone point me in the right direction? to look for? the problem?
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Tom AB9EK
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Re: Oscillations on high bands
I discovered that U8 (an RF switch) was not working on my LPF board. It provided very little isolation. I measured this by removing the LPF control board from my radio and testing it a NanoVNA and the LPF board testing sketch. I removed the TR carrier board, connected the transmit and receive lines together with a short piece of wire, and measured the transmission between J23 (the output of the LPF) and J18 (one of the BPF inputs) as shown in this diagram:
?
?
?
Here is the measured transmission between these points before and after I replaced U8:
?
?
After I replaced U8 I got very low feedback between the output and the input of the 20W amplifier, as shown below. I will reassemble my board now and confirm that this remains the same when running the latest software.
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?
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Re: boards and kits and stuff
Great Terrance, thanks for the post. ?I hope others results will be good too. ?
Dr.?William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ ? Owner - Operator Big Signal Ranch ¨C K9ZC Staunton, Illinois ? Owner ¨C Operator Villa Grand Piton - J68HZ Soufriere, St. Lucia W.I. Rent it: www.VillaGrandPiton.com
email:??bill@... ?
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On Mar 29, 2025, at 8:03?PM, Terrance Robertson, KN6ZDE via groups.io <tmrob4@...> wrote:
? I can report success with Bill's display driver board and also a caution.? I accidentally connected the display driver board to the Main board offset by one row and blew the MISO line.? Bodging that signal across the board, I was able to run the T41 display with a three-foot cable.? I couldn't run the display with a six-foot cable.? I don't think that was due to my unaugmented MISO signal.? The board will drive the display on a shorter cable without the MISO signal at all, though at a sluggish rate.
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? <IMG_20250329_162332274.jpg>
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Re: boards and kits and stuff
I can report success with Bill's display driver board and also a caution.? I accidentally connected the display driver board to the Main board offset by one row and blew the MISO line.? Bodging that signal across the board, I was able to run the T41 display with a three-foot cable.? I couldn't run the display with a six-foot cable.? I don't think that was due to my unaugmented MISO signal.? The board will drive the display on a shorter cable without the MISO signal at all, though at a sluggish rate.
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K9HZ
JerryP