Re: QMX output is always 2W on all bands
On Fri, Apr 4, 2025 at 06:16 PM, Jeffrey W Moore wrote:
some of your screens show input voltage of 12.8v. ?Others show 11.8. ?Is that what you see there? ?Is the supply voltage being reported inconsistently or are you varying it?
Hi Jeff,
First of all, thank you for your reply — I really appreciate you taking the time to help!
In my previous post, I was experimenting with different input voltages using a bench power supply to see if the transmitter’s voltage and power would change accordingly. My theory was that the output power should increase at least somewhat linearly with the input voltage. However, regardless of the input voltage (ranging from 10.8V up to 12.8V), the output power changed only 0.4W.
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Re: QMX+ SWR sweeps with SSB firmware?
Stan --
And it shows up when I am making my first attempts to transmit.
-- rec --
On Fri, Apr 4, 2025 at 07:31 AM, Roger E Critchlow Jr wrote:
I'm sure there's a reasonable explanation for all this
Roger,
This behavior could result from a cold solder joint in T507 or its associated circuitry.? Temperature can change its connectivity.
Stan
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Re: #qmx #SSB Firmware beta 1_01_003 release
#qmx
#ssb
Hans,
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I set the QMX to "practice" mode whenever I want to disable the transmitter and use the QMX as a receiver only in CW, DIGI or SSB mode.
This makes sense when I listen with a random non-resonant antenna and want to avoid transmitting in any mode, even the beacon.
Please maintain a simple way to disable the transmitter
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73, Carol KP4MD
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On Sat, Mar 22, 2025 at 04:35 AM, Hans Summers wrote:
1. Practice mode does not make sense in SSB I guess. When enabled in CW Keyer menu and SSB mode is selected it could be temporarily disabled and then when CW is selected again it could be automatically re-enabled.
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I agree but I think this his already the case isn't it? Doesn't SSB ignore practice mode?
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Thank you Paul and thank you George.
73! de Bekir TA2RX
5 Nis 2025 Cmt 05:12 tarihinde George Korper via <georgekorper= [email protected]> ?unu yazd?:
Hi Bekir,
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With the supplied parts, and the circuits as designed,
as the frequency increases the output will diminish.?
So far I haven't seen a post that shows otherwise.?
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73,
George
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Hi Bekir,
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With the supplied parts, and the circuits as designed,
as the frequency increases the output will diminish.?
So far I haven't seen a post that shows otherwise.?
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73,
George
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The setup I used is in the image below:
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Power supply is from 3, 3400mAh 18650 Rechargeable Batteries in the
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Microphone was made from a old earphone/mic PTT - seen in the front with silver button and hot glued foam windshield.? This tiny mic. works very well for what it is.
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Also shown (on the right) is my Iambic key that I made and encased in figured wood :)? I prefer this to a duel paddle key, though it takes two hands to use.? I have a bulk supply of the components, including PCB, for the small VK3IL Pressure Paddle key if anyone is interested in it as a kit or complete.
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This was connected up to my 160m EFHW!
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Huge thank you to Hans for making the QMX even better!!!? As an old programmer I am in awe how Hans can make such a simple LCD interface and a few buttons work so well together.
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Such great performance from such a small 'package'.
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Myles ZL4MDX
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I rather doubt that's true... If I understand, the differences in output between every unit have more to do with variations in the parts (the output transformer, toroids and associated caps of the filters, and possibly the BS170's).?
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Paul -- AI7JR
On Apr 4, 2025, 18:17 -0700, ta2rx bekir via groups.io <ta2rx.bekir@...>, wrote:
I seem to remember reading a post that when powered with 9V, QMX+ will give a steady 5W output on all bands, but I cannot find that message now.
Is this true or is it my memory playing a game on me?
73!
de Bekir TA2RX
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Re: QMX(+) Build experience, Poor Audio Filter Sweep/RF Filter Sweep/Image Sweep/ADC IQ test and resolution with new PCM1804
Karl, previously you wrote that "The signal is also present on pins 1&2 IC408 but not on pins 3,4, 12 thru 15"
Has this changed?? This is proper switching - the signal being seen on both parts of one coil,? but not the others.
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I seem to remember reading a post that when powered with 9V, QMX+ will give a steady 5W output on all bands, but I cannot find that message now.
Is this true or is it my memory playing a game on me?
73! de Bekir TA2RX
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Re: QMX output is always 2W on all bands
Hello Igor,
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some of your screens show input voltage of 12.8v. ?Others show 11.8. ?Is that what you see there? ?Is the supply voltage being reported inconsistently or are you varying it?
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also the bias should always be steady at 30ma. ?The QMX is actually reading a voltage which (if everything else is right) should correspond to bias current. ?So this is an indication that something downstream of the bias circuit is not right.
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whenever I have a repair where the output is consistently too low, I get suspicious of T501 - the output transformer. ?
I think I would track down each of these anomalies thoroughly and separately.
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let us know
--
73
Jeff Moore
W1NC
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Re: Available Hand Mics for QMX SSB ?
Just got mine from Erick for my QMX. Used a tiny hot glue gun spot to add just a touch length to button to make it easier to use. Thankyou @Erik Larson, The blue is nice, good choice.
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Re: QMX+ new build AGC does not work.
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On Apr 4, 2025, at 7:49?PM, Stan Dye via groups.io <standye@...> wrote:
? It may work to turn down the agc threshold to about s6 or even lower.? My agc didn't often activate when I used the default threshold.
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I had the volume turned up to hear quiet cw signals, and so my speaker was being over-driven by the few very strong cw signals. So I needed to turn the agc threshold down to make the strong signals weaker.
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Re: QMX+ new build AGC does not work.
It may work to turn down the agc threshold to about s6 or even lower.? My agc didn't often activate when I used the default threshold.
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I had the volume turned up to hear quiet cw signals, and so my speaker was being over-driven by the few very strong cw signals. So I needed to turn the agc threshold down to make the strong signals weaker.
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Re: SWR and PWR does not show lcd
On Fri, Apr 4, 2025 at 12:16 AM, <ec7zv0@...> wrote:
The tests are in DIGI mode, that's why SWR & Power don't appear during TX.
No, you misunderstand.? The power and SWR indicators should work fine in DIGI mode.? It is only the agc and s-meter that are not implemented.
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If your power and SWR indicators are not working, please check that they are enabled in the menu.? If they are enabled, you may have a bad connection at T507 such that the processor can't read the power and swr.
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Stan KC7XE?
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Re: QMX output is always 2W on all bands
A few more data points w/ power supply connected:
Supply Voltage | TX Voltage | TX Power | SWR |
10.8 V ?| 9.4 V | 1.9 W | 1.18 |
11.8 V ?| 10.2 V | 2.1 W | 1.18 |
12.8 V | 11.0 V | 2.3 W | 1.17 |?
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Re: QMX(+) Build experience, Poor Audio Filter Sweep/RF Filter Sweep/Image Sweep/ADC IQ test and resolution with new PCM1804
Stan, you must be in Houston, because we have a problem! No matter the freq the signal is present on all L40X coils....there is a whole lot of switchin' not goin' on!
--
73
Karl
KI4ZUQ
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Re: Gibberish characters appended onto end of Message 1
On Fri, Apr 4, 2025 at 05:53 AM, Braden Glett wrote:
Do you happen to know if there's a list of recognized bugs to be fixed,
Hans regularly reads messages posted here, and puts the bugs on his list.? As far as I know such a list is not published.?
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I have a QMX (80-20) for 12 V that I built last year. It worked fine on FD, and was used occasionally since. A few weeks ago I was running it into a dummy load. Controlled by fldigi. Power was a LiFePO? through a regulator at 12 V with a 1.5 A current limit.
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After messing around with the fldigi settings until I got it to "transmit" into the dummy load. Output power and input current looked good.? Then I got distracted doing something else. After some time I looked at the regulator and it was showing 6.1 V at 1.5 A out. The radio is on, and the display works, but obviously something is seriously wrong.
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WSJT-X communicates with it. I can change frequencies and modes.
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I looked at the back of the main board with my IR camera.? The hot spots appear to be associated with Q507 and Q504.
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So I've blown it up, but I don't know what I did. Is there a troubleshooting guide? I've opened it up and there's nothing visually apparent.
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In talking this out I've sort of convinced myself that I have a shorted Q504, drawing too much current and heating up Q507. Does anyone have any better ideas? Is there any way to test this hypothesis other than cutting Q504 out of the circuit and seeing if the excess power draw goes away?
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Take this one, it's the same.
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73, Rajko DC0IT
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Re: ProgRock2 programming??
?Hi Alan,
I measured the voltage on the HC6 socket and found negative .1 volts on one side and zero on the other. All the sockets measure the same negative voltage in the instrument. This obviously isn’t an over voltage issue for the PR2 and maybe the negative voltage killed the one I configured for the frequency I needed. Like I said, it appeared to work for a minute or so, then stopped.
I’m not sure what I can do here other than pull filament voltage (tube equipment) rectify it and then put a 5 volt regulator on the rectified voltage. I would do that only on the three crystals I planned to use the PR2. I’ve got plenty of room under the chassis for the extra components but the time needed to get the 5v regulator (I don’t know if I have one handy) just adds time to my solution and in hindsight I may have been better off just ordering the crystals.
Thanks,
Tom N5AMA
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On Apr 2, 2025, at 7:12?PM, Tom Smith <n5ama@...> wrote:
?Thanks Alan, I’ll measure the xtal socket and see what’s on each pin. I’ll have to be careful to put the voltage pin on a socket with 5v regulated voltage.
73 Tom
On Apr 2, 2025, at 1:50?PM, Alan G4ZFQ via groups.io <alan4alan@...> wrote:
?On 02/04/2025 14:59, cct314159 via groups.io wrote:
- Even though they are "rated" for "12 volts" *don't even think about running one at that voltage:* I'd avoid going above 10.0 volts. Yes, that reminds me. I tested with 12 volts and it certainly got a lot hotter than I expected.
The ones I use are fed from 5 volts and keep cool.
73 Alan G4ZFQ
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Igor
Carol KP4MD
Paul - AI7JR
Paul K7VIQ
Dick Hanson
Karl