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I've obtained some spectrum analyser images of the output from my QMX running at 12.5V.? This is in preparation for fitting Zeners so we can check before and after.? This is the before.

Is this the information that we need to check the performance? I'm not an expert at this and would appreciate knowing if more data is needed.? I don't intend to keep soldering and unsoldering Zeners.

I'm running the QMX into a home made 38.7 dB 8W 50 ohm attenuator (4 x 51R 2W SMDs arranged 2x2, then a 2k2, then 2x100R SMDs).? I've a 10W 20dB attenuator coming.

Spectrums look fine to me, well within the legal requirements

Within your "QMX power and voltage tests" I se the TxV voltages are significantly less than the supply.? I see the same with mine. I think it may be the attenuator ahead of the processor's A/D.? Next time I have my QMX apart? I'll check the actual voltage.

Hi Chris,
thanks for sharing the spectrum images.

Although my comment is not useful for you here, I am glad about this publication, because it gives me the opportunity to compare my own measurements with the FA-NWT plus. The conditions are similar: 38 dB attenuator, but only 9 V voltage supply.

Here are my measurements for 80, 60 and 40 m: