Correction.? Jim, I think your crystal is more like 4kHz off - again not to be unexpected.

--
Peter Lee
G3SPL

On Fri, Jan 27, 2023 at 02:02 AM, Jim Bennett / K7TXA wrote:

I'm running a 30 meter QCX+ powered from a 13.8v regulated supply. After power up I connect my QLG2 GPS cable for a minute or so and then disconnect it. At that point the time in the QCX matches the GPS, which is still running, sitting on top of the QCX enclosure. After six hours, I notice that the QCX is five seconds behind the GPS time!?

I was hoping to use the radio for WSPR, but after seeing this it appears the only way to do that is to leave the GPS plugged in to the QCX 24x7.

Is this normal for the QCX clock to get that far behind in only six hours? :-(?

Jim. The QCX clock depends on the processor 20MHz crystal.? This is nothing special: for most applications the clock frequency is not critical and being a cheap unit, is not adjusted closely in manufacture.? That's why Hans made a calibration of the frequency possible (see Operating Manual section 8.12 for details).? Your crystal appears to be 231 Hz out - which is pretty close as microprocessor crystals go.
If you calibrate the "system clock" using the GPS, it will keep pretty good time as long as the ambient temperature does not change too much.? WSPR needs the clock to be within about 1 second, and you should be able to keep to that tolerance for quite a while.? However, you will need to reconnect the GPS occasionally (or manually set the time against a known good time source).
The TCXO only controls the transmitted frequency, and has nothing to do with the clock.
?
--
Peter Lee
G3SPL

Hi everybody,

I would like to ask a question related to the initial message from Hugh. Do you find necessary to replace all the four BS170s when one of them had "a bad day". I do not care about the relatively cheap transistors but about the PCB.

73! Milo? OK1FMY

John:? There was a thread on here about recent change to the LED behavior.? There is info in the release notes about it as well.

/g/QRPLabs/topic/96336679

Tim Raymer
73 de N0UI

In the assembly manual of the the latest qdx m I noticed in section 2.9? the table describes L2. Shouldn't it be L4 as shown in the diagram??
?My PCB is rev5 M
?Am I missing something?

Wes

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John,

I updated another QDX to 1.08a, and now the RED LED fades in/Out on Transmit. Wondering if this is the new behavior of the LED. As far as I know, I'm NOT in Night mode.
? - John

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Check all the connections at the volume control. That’s a tricky install as you have to bend the tabs. Check the control itself with a VOM DVM.

Gary - no audio from the BPF

p.pippi, thanks for that info.? Reset did nothing to help.

John,
That, the slow fading up and down may still be part of firmware 1.08a.?
There's also a 'night mode' that dims the LED's brightness; I think in that mode QDX's LED does not fade up/down but flashes.

You should be able to find the answer in the notes for each release.

Good luck!

--Al
WD4AH

I am repairing a QDX -- One of the final BS170's (Q10) was blown. It appears to be working now, with the exception of the RED LED. When in TX, it slowly fades ON/OFF, at about 1 second intervals (rather than the 3 quick flashes). PTT seems to be correct - it flashes ON/OFF at one second intervals. It seems to transmit normally, and I've made several contacts. The receiver works great.

I have RESET the firmware, as well as updated to 1.08a. What else do I need to be looking at? Should I replace the other BS170's?

Thanks, John, N0Ts

Hi Mark,

Try resetting the QCX. You find the reset in the ?other“ menu point. Use a 50Ohm Dummy load and go through the alignment menu points again. I had a similar problem. Make sure that when under menu point 8.10 that the volume is at 11. Then you minimize the amplitude. This did the trick for me. I could then hear morse code on the frequency.

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When you adjust the BPF do you hear a tone?

W5SWL ELECTRONICS
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Charles Brown
N4SO/B

Thanks again for the help.

Steps taken:

• Confirmed connectivity from center of BNC through L1, L2 and L3 using DVM
• Resoldered 1 & 2 taps for T1, and confirmed connectivity using DVM
• Went into alignment menu 8.7, adjusted C1 for maximum value.? I was able to get almost full indication, at setting of 4 (attached pic).? The value did not seem to change even when I was able to get the deflection to near maximum...it remained between 4 and 6.
• Revisited 8.8 through 8.10 alignment menu items, saw some minimal movement on the scale (assuming this is normal) but very low levels, so this should be good to go.(low values)

Still no audio output, tried several different headsets/earbuds. Still no TX when pressing down on the microswitch.

Gary, no audio at all.

Ron, I will re-check again the large windings on T1 to confirm connectivity.

Hello Hans Abi
When I entered the 2200m or 630m or 4m values (not at the same time) transmit becomes disabled

It was very late and I didn't push to solve it.

tomorrow I'm returning to Istanbul, there I will give another try

73 muhsin TA1MHS

note: mixture of heisenberg uncertainty principle and?schrodinger's cat?situation

?