Hi Ed, I am no expert on wspr but here are my findings.

5 original QCX's,? 80, 40 (x2), 30 and 20 meters. Some mounted in cases others breadboard open plan. All work okay. Drift can vary between 0 and 4Hz.
Run okay with or without GPS.

1 QCX Mini 20. Minimal number of spots with the original 27MHz crystal. Changed the crystal for another 27MHz one and number of spots improved.? Drift was usually 4Hz on most spots. Replaced 27MHz crystal with TCXO and hundreds of spots. Drift usually 0Hz, occasionally 1Hz but I put this down to the receiving station drifting. Runs okay with or without GPS.

1 QCX+ 40. Fitted with TCXO from first building.? Hundreds of spots. Drift 0Hz. Runs okay with or without GPS.

Running with GPS. If you run with a GPS it should be noted that this will not prevent drift, especially in the 27MHz crystal. Drift occurs during the transmission period and if it is greater than 4Hz then the spot will not be recorded. The TCXO does not appear to drift during transmission.? At the end of each wspr transmission the GPS will check the crystal frequency (27MHz or 25MHz depending if TCXO fitted) and apply correction before the next transmission. It cannot apply correction during the transmission period.

Conclusion. As Hans states, the QCX Mini may be more prone to drift because it is more densely packed than the original QCX's. In my case I found that a TCXO solved the problem and I think that both the Mini and + should be fitted with the TXCO as standard.
73 Dave M3PMG

On 22/08/2022 21:34, Scott W wrote:

The QDX works very well on Receive - all bands.? However, on Transmit, I cannot get a single station to hear the QDX.

Same setup, QDX instead of ICOM, approx 4w (as measured on Elecraft W2 with SWR < 2 on all bands), hundreds of successful Receive spots on all bands,?? 0 Transmit spots on all bands-? no station is hearing the QDX on any band

Scott,

This is with an in-line meter confirming power out of the antenna socket?
Can you monitor the transmission as it happens? If frequency and timing are correct drift is the only other factor that often gives troubles. Although this is not normally a problem with a QDX.

Is it possible that the QDX can transmit 4w but the audio signal within the transmission has somehow been significantly attenuated ?

Note that WSPR, and the QDX involves a single tone. A single RF signal that varies in frequency about every 0.8 seconds. The audio does not appear until it is received by a SSB receiver.

73 Alan G4ZFQ

On 22/08/2022 21:01, Mike KK7ER wrote:

I'm hoping someone with Windows USB audio experience can offer an idea here.
My son and I activated a park successfully with a QDX v3 using a Windows 11 laptop.
We moved to another park and could not get wsjtx to find the audio device (despite CAT control working just fine).

Mike,

Assuming that this is not a changed Windows microphone privacy setting.

In the past I've seen a few USB conflicts where a combination of devices causes one to malfunction. A wireless mouse receiver is a common problem.
Or, something works on one USB socket but not another.
Sometimes experimenting with a compatible hub can solve the problem.

73 Alan G4ZFQ

Can't we use some thermal pads to dissipate heat to the aluminum case?

I run 7? QCX WSPR rigs including on 20. I do not use TCXO in them but all have GPS. If you set up exactly as in the op manual which uses 20 as the example it should work.?
You have a 5 alphabet- numerical space call just like Hans.

Thank you for the design, Hans!? I thought it was more than 5 years old though.? The first real ham radio kit I built was the QCX-Mini.? I really enjoy using the radio though I have to admit, I don't use it as much as I should.? The first reason is my Morse is still pretty slow and second, it feels silly to plug in when my base station costs multiple thousands and is capable of up to 800w on CW.? When I do get the QCX-Mini plugged in, it is a real pleasure though.? Maybe I should build a QCX+ so it sits on the desk all the time asking to be used!

Joshua
KJ7LVX

Should I conclude that I must order the TCXO for WSPR to work? I don't want to start a mail-storm, but how many of you have got WSPR working and getting spots? How many are getting spots without the TCXO option? How many with?

thanks

Ed
WA7EM

--
Colin Kaminski - K6JTH
https://www.qsl.net/k6jth/

The one I got from you, matching the one on the left, is wonderful. I found in using it that I could have used a button, like the Navy keys. The rounded lever on the new design can serve, but what I like best is the hole in the middle of the whorl. I'm tempted to drill one in mine to match it. Then I could take a key button that came with my CW Hotline kit that I didn't use and attach it with a bolt through that hole. I find that I need a button to gently grasp, or my old lady shakiness makes it really hard to use as a straight key. I usually use the V. 1 key you made by setting it on its side, and keying with my thumb. I did that at Field Day this year. I've got more fine motor control in my thumb these days.

The new one IS an improved version. I highly recommend Colin's keys!

73,
Gwen, NG3P

Scott, have you updated the firmware of your QDX? I had a similar problem with my QDX. Running at 2W gave me very few spots. Then I updated the firmware and it seems to be working fine.?

A repeat customer had me start a list so it is official. If you would like to be contacted when keys are ready please send me a private message with your name and call sign. I have magnets in the mail from the East Coast. I am hoping for them to show up in a week or so depending on USPS.

Thank you all for the encouragement. It means a lot to me.?
--
Colin Kaminski - K6JTH
https://www.qsl.net/k6jth/

Recently completed a QDX build - I use WSPR exclusively and have done so for the last couple of years so am reasonably familiar with it. The QDX works very well on Receive - all bands.? However, on Transmit, I cannot get a single station to hear the QDX.?

My QDX
Rev 3a in the QRPLabs case, v1.04, C41 ground mod done and tested OK
Receive current - 160ma
Transmit current - varies by band from 700-820ma
Known fault - L12 - 41 turns however I made an error and have a tap at 37 turns instead of 36 - to be fixed

My QDX Test Setup
12v (limited to 1.25a) bench supply, QRPLabs 20w Dummy Load
PC/Windows 10, WSJT-X - WSPR testing done on 80-20m. All PC Audio Levels at 100% max.
QDX Terminal function testing done
Unfortunately NO Scope.

Test Setup Results

Using WSJT-X? WSPR
Using the Tune function or WSPR transmit function I see 18-20v DC at the QRP Dummy Load 'test points' across the bands. This translates to about 4w.
WSJT-X Power Slider set to Max
QDX LED blinks 3 times on Transmit
CAT and Audio links to the PC appear fine

Using the QDX Terminal functions
Audio Sweep - about 55db between the USB and LSB
RF Sweep - when compared to the manual for 40m it is not similar - band pass is flat between 5 and 10Mhz as opposed to 0.5Mhz in the doc.? Other bands appear to have a very wide band pass as well.
Transmit Test - I see very close to 19-20v DC on the QRP Dummy load (measured at the dummy load test points) across the bands

As a further testing exercise I connected another PC/WSJT-X to an SDR within 5 meters of my Test Setup.? I can successfully receive/decode the WSPR transmission from the QDX Test Setup. It is exactly on frequency within the 200hz WSPR window. The purpose here was to determine if the QDX was transmitting the WSPR signal and at what frequency - it seems OK.? ?? ?

Real World Test Results

Using my ICOM rig
ICOM 7100, approx 1w (as measured on Elecraft W2 with SWR < 2 on all bands) , 80-10m EFHW, PC with very accurate clock timing,? WSPR tests on 80-20m,? hundreds of successful Receive and Transmit spots on all bands

Using my QDX
Same setup, QDX instead of ICOM, approx 4w (as measured on Elecraft W2 with SWR < 2 on all bands), hundreds of successful Receive spots on all bands,?? 0 Transmit spots on all bands-? no station is hearing the QDX on any band


Is it possible that the QDX can transmit 4w but the audio signal within the transmission has somehow been significantly attenuated ?

Although I have double checked the build document I have limited experience in building kits so it is 99% likely I've made an error somewhere along the way.??
Any thoughts or guidance on what steps I should perform next to troubleshoot this would be welcomed and appreciated.
Thanks,
Scott, VE3OCB

开云体育

Take a look at Pg35 in the manual and see if 8.5 might be your problem. I f you have the TCXO installed there’s a difference also.

开云体育

Great idea Ted !

These meters, MFJ-884s - feature a scale calibrated from 0 to 2, and it can be set to read 0-2 watts, 0-20 watts, and 0-200 watts.? I may be useful for someone who wants to measure very low TX output levels.?? They appear on the popular Internet auction site fairly regularly but at ridiculously inflated prices, as you can see from this example. I was lucky enough to snag one at 1/3 of this price - quite reasonable.????

Dave K9SW