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QMX+ Power Output Question
I finished my QMX+ kit 2 weeks ago.? I built it for 9V, and held my breath as I powered it up for the first time.? ?Everything seems to work fine, and all bands receive and transmit.? I called CQ a few times on CW and saw typical results on the reverse beacon network.? ?I have also worked some FT8 on various bands.? ?So overall, I feel like it is a successful build.? ?That being said, I do have a question about the power output.? ?Running into a dummy load, I get the output as listed below.? ?Are these figures typical on the higher bands, and if not is there anything I can do to help increase the output to where it should be?
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73, Jim (w8ykg)
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160M? 5 Watts 80M ? ?5 Watts 60M ? ?5 Watts 40M ? ?4 Watts 30M ? ?4 Watts 20M ? ?3.5 Watts 17M ? ?3 Watts 15M ? ?3 Watts 12M ? ?3 Watts 10M ? ?2 Watts 6M? ? ? 1 Watt |
开云体育I have a factory built unit and your output looks good to me. Very similar. ?Those that tinker trying to get a little bit more out of theirs write up their sad stories here and ask for help. Don’t worry. Be happy.Dave K8WPE On Apr 1, 2025, at 3:40?PM, secondchancesailor via groups.io <jagillaspie@...> wrote:
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Thanks for your input Dave (and Jeff).? It's good to know my QMX+ is not too far out of line with others.? ?I am not losing any sleep over the lower output on the higher bands, I was mostly concerned about 10 meters.? I did try to more evenly space the windings on the toroids as Jeff suggested, but ended up with the same results, so I think I am done.? Now I am focused more on why WSJT-X refuses to run on one of my my Windows 11 computers.? ?It was working, and then just stopped.? Have uninstalled and reinstalled it with no joy. (No big deal, it runs fine on my other computers).
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Tnx and 73,
Jim (w8ykg) |
Might not be the issue but ....
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Just the other day I installed the latest version of FLDigi on one of my Win 11 laptops. Then both the new and old versions of FLDigi AND WSJT-X quit recognizing all of my Q's. Even though the expected com ports would appear and disappear in Dev Manager when power cycling the Q's? Got lucky on a Google search ... There were a bunch of hidden USB and Audio Devices in Dev Manager ( click on show hidden devices). Uninstalled all the zombies, rebooted and all good again. * Now, if I can get McAfee to check and bless the latest hamlib release which gets immediately quarantined when I try to pull it off SourceForge I can try out the latest WSJT-X version. Sigh .... GREG KI4NVX?
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Jim - How do the LPF (Low Pass Filter) sweeps look for the upper bands?? If the low pass filters are kicking in a little too low, you can back out a turn or two on the LPF coils to raise the cutoff frequency.? I had to do that on my QMX+ to keep the LPFs from reducing my output on the higher bands.?
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Steve KA0SM |
On Thu, Apr 3, 2025 at 11:50 AM, Steve M wrote:
I had to do that on my QMX+ to keep the LPFs from reducing my output on the higher bands.?You might check to ensure that you have not spoiled the harmonic suppression in the process.? Hopefully the increased power is not due to harmonics also getting through; the presence of harmonic energy will cause inflated readings on a diode-based power measurement.??
Thermistor-based power sensors (HP 848x for example) do not exhibit this effect and measure true RMS power which is why I prefer them.
73, Don N2VGU |
Sure hope that's it for you too.?
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Greg
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When I did the initial LPF sweeps I noticed that filters were attenuating the signal within some of the bands.? Adjusting the spacing of the turns on the coils made little difference.? Backing off a turn on the coils for the appropriate LPFs moved the attenuation outside of the band.? The filters are still fully attenuating the second harmonic and above.
Hans posted a video on this process for the QCX+ --
Steve KA0SM |
On Thu, Apr 3, 2025 at 07:52 AM, Greg McCain wrote:
Now, if I can get McAfee to check and bless the latest hamlib release which gets immediately quarantined when I try to pull it off SourceForge I can try out the latest WSJT-X version. Sigh ....Greg, I had to turn off McAfee virus scanning while downloading the file and unzipping it. After I had the hamlib.lib file out of the zip and deleted the zip, there was no longer a problem with it, and I successfully dropped it in the wsjt-x folder.
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A few other files (JTAlert) I had to put in the 'Excluded files' list on the real-time scanning tab of McAfee.
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Thanks.
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I knew about that option but want to try the 'send to McAfee' option to see if I get a response and closer validation from them. Might help others going forward.? If not, successful with that, I'll dig into the memory banks and see if I can figure out how to run the package validation checksum from the SourceForge files.? My current WSJT-X is recent and working fine for my QM's and QD's on two, fully up to date, Windows 11 laptops. So not desperate :)? GREG
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Appreciate the info and that you checked the file too.
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And of course, the great general group support. I've saved a bunch of your troubleshooting recommendations and signal flows explanations.? GREG
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Yep. Ran into that too.
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Appreciate the possible alternative work around. GREG
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