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Re: QRP-Labs

 

On 2025-03-30 18:17, Dave Mueller AA3EE via groups.io wrote:
It is. They become extremely sensitive to load mismatches. The group
is full of reports of them failing, especially when an external tuner
is looking for a match.
*** I guess that's why the radio has a built-in SWR bridge, and fairly
fussy protection software.

Since I'm operating it into my Tiny Linear, the radio is isolated from antenna
SWR. Nobody hears me at 5W, anyway :).

- Jerry, KF6VB
Re: QRP-Labs

 

On 2025-03-30 15:50, Greg KF5N via groups.io wrote:
Did you get a chance to look at the spectrum?
That seems like a lot of power for BS170s!
*** It's a digital PA. In the schematic, the BS170's are fed
RF by LOGIC gates. I think it's what's called a "class E".

They don't even have heat sinks. They output 5W without
breaking a sweat.

The spectrum looks good on my FTDX10. I haven't hooked it up to
a spectrum analyzer yet.

- Jerry, KF6VB






--
73 Greg KF5N
Links:
------
[1] /g/SoftwareControlledHamRadio/message/33305
[2] /mt/111990371/243852
[3] /g/SoftwareControlledHamRadio/post
[4] /g/SoftwareControlledHamRadio/editsub/243852
[5]
/g/SoftwareControlledHamRadio/leave/10484476/243852/1943518115/xyzzy
Re: QRP-Labs

 

It is. They become extremely sensitive to load mismatches. The group is full of reports of them failing, especially when an external tuner is looking for a match.
Dave
Re: boards and kits and stuff

 

¿ªÔÆÌåÓý

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.
Re: QRP-Labs

 

Did you get a chance to look at the spectrum?
That seems like a lot of power for BS170s!
?
--
73 Greg KF5N
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.?
?
Tim?
W4YN
Re: Need HELP!!!!

 

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!
Re: Need HELP!!!!

 

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!
QRP-Labs

 

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
Display driver board

 

¿ªÔÆÌåÓý

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@...

?
Re: Need HELP!!!!

 

¿ªÔÆÌåÓý

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@...

?


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
?
Will keep on looking for the problem.
?
Tom
?
Re: Need HELP!!!!

 

¿ªÔÆÌåÓý

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@...

?


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
?
Will keep on looking for the problem.
?
Tom
?
Re: Need HELP!!!!

 

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
?
Will keep on looking for the problem.
?
Tom
?
Re: Need HELP!!!!

 

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.....)
?
check the poor mainboard and connect without teensy the cables 1by1 and check the voltages! special on 3.3V rail!
?
I hope you are successful
?
?
Re: Oscillations on high bands

 

Here's the gain of my K9HZ 20W PA:
?
?
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.
?
?
If I upgrade my radio to include a 100W amplifier (7dB increase in gain), this reduces the margin to at least 10dB.
?
Re: Need HELP!!!!

 

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.

Re: Oscillations on high bands

 

¿ªÔÆÌåÓý

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@...

?


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:
?
<inline.0.part>
?
?
Here is the measured transmission between these points before and after I replaced U8:
?
<inline.1.part>
?
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.
?
<inline.2.part>
?
?
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.
?
?
?
Re: Need HELP!!!!

 

Also don't forget you have to slice the trace on the Teensy to disconnect the USB power.
?
--
73 Greg KF5N
Re: Need HELP!!!!

 

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?
?
?
Tom AB9EK
701 - 720 of 33935