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Hi all, This is my experience?with the SSB beta release. After much fear and?consternation, I took the plunge today and installed the SSB beta firmware in a QMX Rev 1. I attempted to do a calibration on Putty, but the R and O commands would not work. This could be due to my inexperience with Putty or a failure to understand the?instructions. I disconnected the?QMX from my laptop and was able to run the calibration from the Hardware Tests screen on the radio. The QMX got a little warm, but the?calibration was apparently successful. Afterward, I checked the CW power output on?several bands, and it appeared to be normal (same output?I had before the calibration). I did not put the QMX back on Putty to check the calibration curves. I tested the?SSB mode with a QRPguys microphone?kit and made 8 successful?phone contacts on 20M. Audio and signal strength reports were good. The?mic is covered by a cutdown foam windscreen purchased from Amazon, and the only mic setting I adjusted?was compression set at 5. I found the best output occurred while talking straight down into the mic held about an inch from my mouth. Probably because the mic element is a setback from the vinyl cap. I have not tried other?bands yet.? I am mainly a CW op, but after the successful SSB implementation I may have to start making more phone contacts. I'm almost embarrassed to say it was fun!? 72, Randy NR5N |
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New firwware#firmware
So far everything seems to be functioning well. I have noticed that when using the swr tune function that on some bands the swr reading does not change while tuning an antenna and I have to turn it off then on again to get a new reading. This didn't happen before and would change as I operated a tuner.
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Randy
VE3JO |
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Re: Broken L512 toroid.... T37-10 (Black)
Here's one source Bill Ron On Sun, Apr 6, 2025 at 2:08?PM Bill VE4WJM via <mayberrywj=[email protected]> wrote:
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Re: Swr meter in SSB mode
That's the same for me, everything is fine in CW and Digi but SSB is weird On Sun, Apr 6, 2025, 5:20?PM Barry Palmatier via <BarryPalmatier=[email protected]> wrote:
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QMX+: Broken L102
I finished building my QMX+ today and on inspection I see I've broken the core of L102, one of the switching power supply inductors. It looks like both leads of the winding are still connected to the board. I'm not going to try powering it up until I get a couple of questions answered.
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1) It looks like the core snapped off almost flush with the bottom flange, which is still attached to the PC board. The ends of the winding are still connected to the board. Would it still work if I just used cyanoacrylate glue to put the core back together?
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2) If the answer to #1 is "no," can anyone suggest a suitable replacement inductors that's available in the U.S.? Digi-Key doesn't seem to carry anything of similar size that's greater than 220 uH. This one is 330 uH.
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Dave, WD8CIV |
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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, these results are a bit confusing to me.
If I understand, you are putting in a 14MHz sine wave signal at about 15mV, and are tuned to 14MHz.
With that setting, you should see the 14MHz signal at the input of IC408, pin 5, and on its output, but only on pins 1 and 2.? The true output is on pin 1, and it gets coupled through the shared BPF L403 to pin 2.
You should not see the signal on IC408 pins 3 and 4 or anywhere else.? If you do, you likely have a short somehow between L401 and L403, or perhaps a failed IC408.
And the signal should also be seen at IC402 pin 11.? If it is on IC402 pin 11, that would be from the above-stated short.? But since you see it very weakly or not at all on pin 11, it means something is wrong with your soldering or winding of L403.
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The signals you are measuring on IC403 pins 7 and 9 shouldn't be there, or perhaps are from poor grounding during measurement.? And I don't think they are at all related to your input signal, if it is indeed a 14MHz sine wave.
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So check L403 carefully, and any possible shorting to L401.
Stan KC7XE
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Re: Swr meter in SSB mode
Interesting.??
Mine doesn't do that (tested in SSB mode on both a QMX and a QMX+ into a dummy load).
Sometimes at the instant of pushing the PTT key, the SWR indicator does jump up, but then goes back down and doesn't continue to change.
Testing instead into an antenna, which shows 1.3:1 on the Hardware test / Test SWR function, I see the swr indicator go up one or two 'bars', which is correct, based on the operational manual's definition of an increment of 0.2 per 'bar'.
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So I'm wondering what is different in your setup that changes the behavior?? It's almost as if you are looking at ALC or mic AGC rather than SWR, but I don't think it is supposed to be able to do that.
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Stan KC7XE. |
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Re: QMX WSPR Anomaly
The operations manual states the following, which looks much like your display (with the exception of the CW):
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During the actual WSPR message transmission, the display shows something like this:
14,097,140 122 2 G0UPL IO90 37 The elements of this display are explained as follows: 14,097,140 Transmission frequency (tone 0) 122 Current symbol is 122 (of 162 symbols making up a WSPR transmission) 2 Current tone being transmitted (one of 0, 1, 2 or 3)
G0UPL Callsign encoded into the transmission IO90 5-character Maidenhead Locator square, encoded into the transmission 37 Power in dBm, encoded into the transmission And also:
The beacon function can also operate a CW or FSKCW (slow narrowband) beacon.
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Perhaps you have enabled the CW function of the beacon?? |
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Re: About calibration
No, you don't need to do the calibration process.? In that case the phase and amplitude corrections are simply not performed, and you will still get reasonably good results.
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If you do the calibration process, you may transmit better audio.? The calibration process is detailed on the qrp-labs page where you access/download the beta firmware.
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Stan KC7XE |
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Re: QMX quit working
#qmx
#troubleshooting
On Fri, Apr 4, 2025 at 03:52 PM, pgramsey, N9LFF wrote:
I've sort of convinced myself that I have a shorted Q504, drawing too much current and heating up Q507I think you are correct, based on the evidence stated.? Did you perhaps leave your QMX in tx mode when you turned away??? Extended tx time could have burned one or more finals at full voltage/power.? You can try measuring resistance between the leads of Q504 (and the other three BS170s).? Mine shows in-circuit S-D resistance of about 6.8k.? The resistance between G and S or D varies depending on which polarity I connect the probes - but always over 150k. ? |
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Re: Available Hand Mics for QMX SSB ?
On Sun, Apr 6, 2025 at 10:58 AM, Jared N7MAW wrote:
For those that are using the K6ARK mics, what is your required mic gain?This greatly depends on the particular mic element you get.? The one I received (from one of the kits Erik kindly provided) has much higher sensitivity and dynamic range than any of the others I have tried so far.? I could set my gain at about 58, and the noise floor in the QMX microphone test?is only up about midway into the second 10dB column.? ?
And Erik told me this is from an inexpensive bag from Amazon, 10 for a few dollars.? He says there is a range of performance levels in a bag of these, so your experience may vary.?
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I have ordered the same element Hans used for testing to compare its performance.? It is a bit more expensive, but likely tested to its specs.
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Stan KC7XE? |
Ronald Taylor
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