Hi everyone,
I built the QMX kit configured for 12V operation (the kit was ordered on 13/04/2024), and while everything appears to be functioning correctly, I'm only seeing about 2W of output power across all bands.
Here are some data points and measurements I’ve taken:
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Input voltage to QMX: 11.2V (measured with a Fluke DMM), very stable with minimal drop during TX.
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Antenna/dummy load: SWR monitor seems to be functional and correspond to nanoVNA measurments.
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Power display: Only 1 bar (4–5 dots) shows on the PWR display while connected to QRPLabs' 20W dummy load.
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Measured voltage: The DMM reads ~11V across the dummy load during TX.
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QMX Console app: Shows 9.5V and between 1.8W to 2W output during TX across all bands.
I’m not sure where to start troubleshooting this issue. What would be the best way to begin isolating the cause?
For context, I have the following test equipment available: oscilloscope, multimeter, bench power supply and another working QRP radio for reference/testing.
Please let me know if there’s any other information I can provide to help identify the problem. I’d be very grateful for any suggestions or guidance you can offer.
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Thanks in advance for your help!
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Best regards,
Igor — W6ETA
73
Igor