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Interesting thought.

Karl wrote:

What should the AGC settings be?

First just turn agc off and see if the nature of the issue changes.

If you have the first parameter turned low, like S4 or so, it could be cranking your gain up so you hear the tones much stronger than they are.? This would happen in CW mode.

Measuring again and seeing what the 10 volt rail does during transmit, I see that it drops to about 9.85 volts on the rail and 9.37 or so at the input to Q508. This gives something like 9x10^-7 amps leakage through Q508. The spec sheet for bss123 says that's out of spec as it should be 10x10^-9 amps of leakage even at 20 volts, but I'm not sure that that small amount of leakage would have been enough to blow up the Mux ICs.?

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I may change Q508 as well just to be safe.

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Greg

Just to see how far up my head has been during this 'cranial-rectal inversion' I did a continuity test C422 to R413/R416 which was, of course, successfull!

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Thank you, Stan, for being the lighthouse in the storm!

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73
Karl
KI4ZUQ

What should the AGC settings be?

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73
Karl
KI4ZUQ

My QMX+ audio level seems much lower in SSB mode than in CW mode.

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73, Dan - W2DLC

Hi Mario,

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That's good to know. Will look into it.

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Thanks for posting.

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Cheers.

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Mel. M0KMD

Greg,

I got mine from Digikey.? In this case the shipping will be the worst part.??

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73

Dick

W4PID

I noticed, as some others have, that the built in mic is picking up my voice and other sounds in the room while I am in the mic gain adjustment mode in the terminal.

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73, Dan - W2DLC

Hi Hans,

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Thanks for providing the SSB update, even as beta firmware.

Meanwhile, I have a problem with VFOs:

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- I set VFO A to 7020 kHz, shows VFO A

- pressing VFO A/B switches it to 7027 kHz, shows VFO B

- setting the Band to 20m, freq to 14035.5 kHz

- pressing VFO A/B, shows 14024.5 kHz, shows VFO A

- in my opinion, this should show 7020 kHz, VFO A. Or are VFOs per Band?

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I think this behavior is also in 1_00_027.

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Update: I deleted my earlier message, as I can't edit a message once published and it was unclearly stated and with some operator errors? :-)

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73 de Martin / HB9GVW

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Check your AGC settings?

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M

I get this on 80 meters here, but not 20.

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I wonder whether the receiver BPF tuning (or problems tuning it in early revisions) influences the testing method? I've already asked Hans about this in another thread....

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M

Things generally look pretty good here (if a little confusing sometimes).

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I'm seeing a lot of difference in the behavior between the USB input and microphone - I hope to look into this some more today. I believe Hans is already aware of some limitations of the microphone.

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A suggestion: Perhaps it's best to start off with the microphone processing disabled when trying a new microphone and bring them in once the microphone is basically working and has a decent level setting. I had very confusing results until I tried this.

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However, the real reason I'm posting is to ask whether the linearity testing depends on the receiver performance or whether it's independent of it?

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My revision 1 QMX is one of the ones with wacky 20 meter BPF behavior and I never got back to trying some of the later suggestions to improve the problem as it worked more or less adequately for usual band conditions. This results in funny level curves on 20 meters. I think this was a common problem with some of the earlier units.

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Should I drop everything and try to get the receiver working right before worrying too much about the variations in SSB calibration on 20 meters?

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thanks in advance....

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M

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So I applied 1_01_002 to a low band and high band QMX, and a QMX+. All three updated fine. Low band and QMX+ worked well and calibration was nominal.

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The high band QMX hung and turned off during calibration (was supplied using a regulated PSU so power wasn't cut etc). 30w Diamond Dummy load (15w cont rated) / checked.

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When retrying, the radio gets into a boot loop where the screen clears, backlight turns on, and FW info is displayed. Before getting to the VFO it powers itself off now. Upon trying a hard power cycle (removing power supply, reapplying 12.0v), and clicking the Vol knob to turn on, it booted again, never made it to the VFO screen and made a loud pop. Something died hard. Magic smoke donation to the beta gods. Any ideas? Kind of sad. Was a nice working high band QMX.... Will open to investigate.

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Thanks,

Joe KD2YAR

I have the following items for a QMX that are surplus to my needs.

An unbuilt LCD display and the display mounting board.

Both switching regulators.

Unbuilt control board with the switches and encoders.

Hardware package of nylon screws and nuts, including the headers for above boards.

Includes the key fob too.

Asking $25 plus $10 shipping for CONUS.

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Contact me off list.

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Barry

There's a lot of confusion about the PC microphone connector wiring because the first sound cards that used 3.5mm microphone input usually used tip for the audio and the ring for the bias voltage giving you a choice of whether you wanted the bias or not.

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These days, most devices seem to just use the tip for both bias and microphone - since most microphones elements prefer that approach.

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Unfortunately there's no agreement about whether the tip and ring need to be connected together in case you plug the microphone into an old style sound card.

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You'll need to measure with an ohmmeter between tip and ring to find out, and I suggest always checking this out yourself to be sure.

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Hope this helps.

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M

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Richard,

What voltage were you powering the QMX with? On my 12 V QMXs, they draw about 90 mA at 12.0 V. However, at 7 V, they draw about 150 mA.?

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73, Dan? NM3A

<VE> (with the meaning of "verified" or "copied" or "confirmed") is attested with the same meaning in the ARRL Handbook since the 1949 edition () , and in various historical commercial and military radio operating manuals. I am not sure whether it was used in landline telegraphy at any point though.

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Hope this helps.

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72/73 de Enzo M0KTZ

On Wed, Mar 19, 2025 at 05:24 PM, Pierre - FK8IH wrote:

Why not use different lengths of wire?

73 - Pierre - FK8IH

Good idea!

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73, Dan? NM3A

very low priority correction not specifically related to this version:

di di di dah dit ...-.? <VE>? is decoded as the exclamation mark symbol "!"? (or when using memory, "!" is used to send <VE> ).? The actual exclamation mark dah di dah di dah dah ?-.-.--? is not recognized.?? While the "!" is non-standard, <VE> does seem to have common reference, but I admit not being able to find it in the ITU pdfs.

Reference:

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