If I understand you correctly, you're looking for the WSPR freqs for each band. Page 35 of the QMX operating manual lists them--or did you already know that? In any event I usually aim for a frequency somewhere between the extremes. For example on 20m I usually use something like 14.097.140. Beacon mode works perfectly provided all the parameters are set up right. Hope this helps. Mitch NK3H

Thanks Karl. You are running the QMX via wjst ?

Mine displays the freq that WSJT-X puts in for the band selected.
--
73
Karl
KI4ZUQ

Hans,

I don't know if this is a possibility with the firmware / hardware configuration, but...
Is it possible that the messages programmed in are able to remain within the eprom when firmware is updated.
I use the messaging function of this radio (qmx) a lot (I'm a lazy cw operator hi hi) but always forget to re program them after doing an update and kick myself when out in the field. It's easy enough to use the terminal emulator to re do these when I get back to the pc but a pain in the butt when out in the field.
Just for clarity, I am disabled following a stroke and took to cw as speach was very difficult. But limb weakness means prolonged cw sessions can prove problematic hence using the messaging functions a lot.

Sam
2E1OCT

Can anyone tell me the SCREEN DISPLAYED frequency by band for the QMX please when used in WSPR?

yes I’ve googled it, yes I’ve done all that stuff. I just want to hear what others think. I’m going bonkers now

开云体育

It is possible but I have quite a few different sized micro bits so use just the size necessary for the part to fit through leaving most of the via intact. ?It’s just an option and another way to solve this issue that has worked for me. ?Having or borrowing a high end solder sucker is a better option. ?ChipQuick and a little more flux works well with a cheep solder sucker….. I have done all of the above. ?It’s fun trying this and that and being very careful. ?My last use of removing solder from the board was just heating it up and banging the board against my workbench. ?The solder flew out and I was the “Winner” once again.?

开云体育

I have a different version but they all have a 1/8” plug in for wired connection.

Thanks Hans, for adding the links :-)

Small update on my QMX+.

Like all the cases from QRP-Labs, I really love the QCX+ / QMX+ case. But when you the have QCX+ or QMX+ case it on a desk, the ergonomics aren't that good. Just try to turn the tuning dial and you feel what I mean.?

But luckily I already solved this problem with my and with my experience on the I desiged to re-design the original QCX+ tilling feet so, the they could be used with strong double sided tape.

I used this tape from or if the link is broken, google for "hxres tape".

?

I have very good experience with this tape, it's strong like hell, but this is the first time I tried it for the tilt feed on a case of this size (used it also for the QMX-mini but that case is smaller). So success is defiantly not guaranteed.



The height of the 3D printed tilt-feed is the same as the rubber feet supplied with the QMX+ case. So no wobbling whats so ever.?

??

Now the ergonomics is much better when using the QMX+ on the desk. For now I leave it stand on the work bench for a day and if tomorrow morning the case is still in this position, the tape is approved for this job :-)

--

73 Lex PH2LB?

I installed a miniature toggle switch in the rear panel replacing the power
jumper on the board. Maybe a better solution will come in the future. For
now I can turn off the noise when not using the GPS.

Dave
ve3zzy

Thank you for the suggestions. I removed R306 and replaced with a 1/8 watt 900 ohm resistor.
On either side of the SMA R306 is a large pad making it easy to solder in a larger resistor. Thank you Hanns!
Backlight brightness is perfect now. Easy on the eyes in a dim lit room.

Dave ve3zzy

Peter , before you jump in the company 60dbm.com out of Ukraine but still working has some nice solutions specifically set up for the machines like Hermes Light and even lower power Qrp transmitters . if you will accept 100W out then for 2-4mW in you have a high quality solution using modern components. These boards can be bought as modules or fully built up with auto frequency detection, heatsinking and most importantly a full set of LPFs. What they don't seem to have is high SWR shutdown. The basic board that goes in amp below costs $250 without heat sink and filters . if you used a splitter-combiner design you'd be looking at abt 180W out for 8mW in.

?

100 Watt HF/6m Power Amplifier for Yaesu FT-817, Icom IC-703/705, Elecraft KX3, automatic band switching

$399.00

Linear Tech's AD8009 highspec VIdeo amp is your friend here - costs about 5 Benjamins each from Chicom dealers . THese have been successfully used as driversfor RD 15HH Mosfets in class A to get 7 W linear out. Will give up to 24.7 dBM LINEAR power into a 50R single ended load at 12 V supply, without sweating the silicon. that's 7.7 dBm over your start position.

For Filters, I'd consider just a Heist Two of Hans the genius's Qmx + two band filters to make up a four Pi topology set that would cover from 40-30-20-15 Mhz that does not need to be switched . It would be 50Z in 50 out ... anything outside there in frequency - why bother :-)) ??

Obviously 80 and 60m bands are implicitly covered in any case . Nothing new under the sun - if QrpLabs in Istambul have not done it , then the crows working for the CIA or NSA probably have.

Ahoy there mon !! as Bob Marley would say .. we are sitting here holding our breath waiting for the story that it was a bad solder joint or a plated through hole (ie PTH that take signals from bottom to top of PCB ) which did not work as advertised...

?

do you have traction yet ?

So I am making a second post. I recently assembled a QMX. Fired up at 7v limited to 200ma. Loaded the firmware. The transmit on all band is great with 4 to 5w. This is a 60 to 15m model.

The problem I have is it is mostly deaf. Only if a station is like S9+20 will it exceed the noise level and be able to be heard.

I am posting various sweeps here. First the swr sweep for 40m looks good to me.

Then the RF 40m sweep looks good to me also.

Then the 40m lpf sweep, again I see no issues.
Now the image sweep. This compares favorably to the manual so I believe this is good as well.
Now the AF image sweep. This is similar to the manual, but my lsb is only down -40 and not -60 like the manual shows. I am not sure what would cause this.

Lastly the ADC sweep that Hans just created. I see the I and Q 90 degrees out of phase so I believe that proves my tri filar torroid is fine. The sweep however is not clean like the example. There is significant noise, at least it appears that way to me.

Please if anyone can help. I have my suspicions it is the PCM1804, but I am not an engineer.

Thanks everyone.

How does one use this? It seems to be Bluetooth only.
--
Wayne S.
KF7RCM

You can test for intermittent contact by attaching your VNA and then flexing the wires, connections, etc. until you find the offending part.
73, Don N2VGU

On Fri, Jul 12, 2024 at 04:38 PM, @Ludwig_DH8WN wrote:

I'm not sure about the frequency accuracy of the used VNA

It is typically well beyond what is needed to measure an antenna's impedance which varies slowly with frequency compared to, say a crystal filter.
73, Don N2VGU