Re: 5W mini transmitter for presetting the ATU
You could defeat the SWR measurement in the QMX.?
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Colin - K6JTH?
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5W mini transmitter for presetting the ATU
To all HF specialists:
I use the inexpensive and good ATU100 automatic antenna tuner.
Works well and is very inexpensive, I have already built several.
The transceiver whistles with about 5 watts or a short continuous tone.
Now the QMX has this very good and fast protection circuit. This means that setting the ATU is no longer possible.
Sure, I can briefly connect another transceiver to the ATU, but that's too inconvenient for me.
I want a small device with a frequency display that produces a 5W RF signal at the push of a button to quickly tune the ATU.
Would that work with that:
Si5351A synthesizer module kit +
5W HF PA?
Kind regards, Axel
DL5GT
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FLIR Camera Images of a working QMX
Here are various FLIR images of a working QMX radio - Total output was about 2.5 watts (on 11 volts) into an antenna on 20M and a dummy load on 30,40,60 and 80M. The "shack" was pretty chilly this morning, but mostly these are pretty unremarkable. Nothing on the board got much over 100F.? The finals of course got warm, but nothing remotely concerning. It did inspire me to put a tiny bit of thermal CPU paste under each of them, which helped, but probably not worth the work, especially considering the amount of hours and good performance of this unit.?
The only completely expected thing I noticed was that different diodes would warm up between switching different bands. That's it. I haven't bothered to label any of these because they're frankly boring. Enjoy.?
Bonus is the standard dummy load after getting a few watts for a minute or two. Also boring.?
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On the QRP-Labs webpage for the QMX. Scroll down.
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I have finished building of a QMX v,2 radio.? I can't find the address fpr downloading the firmware.? Where is it?? N7WM.
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I have finished building of a QMX v,2 radio.? I can't find the address fpr downloading the firmware.? Where is it?? N7WM.
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Pic showing CAT wiring to an Arduino acting as a USB to TTL converter
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73, Bernie, VE3FWF
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Here you go
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73, Bernie, VE3FWF
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Re: installed QMX Rev 2 diode mod, now it is deaf
Is it true that the diode mod is only needed on the Rev 2 boards?
Paul -- AI7JR
On 1/16/24 14:48, k9pz wrote:
And now it works, rf filter sweeps keep changing.
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Paul -- AI7JR
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Re: Get to know your dental hygienist!
Your dental hygienist will usually give old picks away for free.? Back when I taught SCUBA, we'd get free dental picks to remove the O-ring from SCUBA tank?valves.? And when one of us got a handful, we'd share them with the divemasters and the up-and-coming students who looked like they'd?become divemasters.
Free is better than $4.99, but it's good that HF has them.? You can also find them at gun shows, usually for a dollar each.
73 Jim NOTQ
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Re: installed QMX Rev 2 diode mod, now it is deaf
And now it works, rf filter sweeps keep changing.
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Re: installed QMX Rev 2 diode mod, now it is deaf
Now my swr sweeps show flat lines at 10. No power out when tuning in diagnostics. Swr protection trips. Dummy load attached.
Yikes. I really broke something.
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Re: installed QMX Rev 2 diode mod, now it is deaf
I did a recheck of L401. Everything seems good. QMX was A+ 100% beofrw i attempted the diode mod.
The issues on 20m and 30m are new, after diode mod attempt.
73 K9PZ
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Yes, Stefan, that is a short! ... JZ
On Tue, Jan 16, 2024 at 5:11?PM Stefan U. Hegner < db4st@...> wrote: Hi John,
Am 16.01.24 um 22:31 schrieb John Z:
> Stefan, that transistor appears to have suffered a gate-drain short.
> You can probably confirm that with an ohmmeter.
I'm measuring 120 Ohms ... that's close enogh to a short for me.
Thanks for the confim. Part is orderd. Hopefully I can report a "solved"
next weekend.
Mni Tnx & Vy73
Stefan.
--
Stefan U. Hegner? ? <db4st@...>
? ? ? ? ? ? ? ?* * *
DB4ST --- German Ham Radio Station
D-32584 L?hne ----- Locator JO42IE
? ? ? ? ? ? ? ?* * *
GPG-Key | C3CC 23A4 FBA8 622B 48AE
F-Print | 4F19 D0EE E39E ABDC 2BCE
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Re: Both QDX units lost ability to transmit?
The slider was all the way up .......... Long pause........
Then checked the volume in the sound manager..........
Longer pause.........
And the winner is .............. The volume controls on the computer sound manager!!!!
Yes Ladies and Gentlemen, I did not look at the obvious problem and there it was all the time!!
Thanks..... And when we meet at the next event you can shake my hand and tell me you knew it all the time.... You were just trying to help me mature a little in the craft??????
Have a great evening and thanks again till your better paid
73
James?
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Re: installed QMX Rev 2 diode mod, now it is deaf
Next, recheck the solder joints at L401. There may be some unremoved enamel remaining on the wires...JZ
On Tue, Jan 16, 2024 at 5:00?PM k9pz < kd9okx@...> wrote: Thank you again.
It was very difficult to install, i think there was insufficient clearance with the case causing the damage.
I was able to goober enough solder on to L503 to regain continuity. 80,60,and 40m are all back in spec.
Tx is stable.
Audio and rf sweeps on 20 and 30m are still terrible.
73 K9PZ
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Hi John, Am 16.01.24 um 22:31 schrieb John Z: Stefan, that transistor appears to have suffered a gate-drain short. You can probably confirm that with an ohmmeter. I'm measuring 120 Ohms ... that's close enogh to a short for me. Thanks for the confim. Part is orderd. Hopefully I can report a "solved" next weekend. Mni Tnx & Vy73 Stefan. -- Stefan U. Hegner <db4st@...> * * * DB4ST --- German Ham Radio Station D-32584 L?hne ----- Locator JO42IE * * * GPG-Key | C3CC 23A4 FBA8 622B 48AE F-Print | 4F19 D0EE E39E ABDC 2BCE
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Re: installed QMX Rev 2 diode mod, now it is deaf
Thank you again.
It was very difficult to install, i think there was insufficient clearance with the case causing the damage.
I was able to goober enough solder on to L503 to regain continuity. 80,60,and 40m are all back in spec.
Tx is stable.
Audio and rf sweeps on 20 and 30m are still terrible.
73 K9PZ
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Stefan, that transistor appears to have suffered a gate-drain short. You can probably confirm that with an ohmmeter.
JZ KJ4A
On Tue, Jan 16, 2024 at 4:20?PM Stefan U. Hegner < db4st@...> wrote: Hi Folks,
Am 15.01.24 um 22:00 schrieb Stefan U. Hegner:
>> [...] test that Q508 is turned on while receiving.? The source and
>> drain should be close to zero volts.
>
> Not so sure on this one: Drain 0.64V, Source 0.07V, Gate 0.69V - no
> matter what band I select. - Is this maybe the suspect? Strange, as
> there was no re-soldering in that vicinity.
>
> [...]
>
> But my interpretation would be a fried Q508 ... so change one BSS123
> MOSFET.
>
> Please confirm this diagnosis
>
As 0.64V at the drain is not close to 0V, I suspect the Q508 ... but I'd
appreciate some confirmation on my interpretation, if that is possible,
before ordering parts and heating up the soldering iron ... Thank you so
much.
Vy 73 & mni tnx
Stefan.
--
Stefan U. Hegner? ? <db4st@...>
? ? ? ? ? ? ? ?* * *
DB4ST --- German Ham Radio Station
D-32584 L?hne ----- Locator JO42IE
? ? ? ? ? ? ? ?* * *
GPG-Key | C3CC 23A4 FBA8 622B 48AE
F-Print | 4F19 D0EE E39E ABDC 2BCE
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Re: QSX: I'd like to purchase a fully assembled & tested QSX
My two QMXs are on the waiting list...YIPPEE !!!
72,
Bill, N4QA/4
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Colin Kaminski
Paul - AI7JR
KB9NBL
Bill, N4QA/QRP