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Hi,
I just completed a QMX rev 1 and the rf signals are weak on all bands 80-20m.

A signal of? S9? is very low, a 2oDb + signal is loud and clear.

I've checked for solder bridges, re-soldered? T507 enameled wire and no improvement.

It appears just like a very weak rf station.

When I was winding T507 I wasn't sure about the winding direction.? I was not sure if it makes a difference.

Any thoughts?

I was thinking of removing T507 and reversing one of the winding directions, or just rewind the whole thing and making a loop when I finish the?
first winding, then continuing in the same direction for the second winding.? That's a fair amount of work if that's what's wrong.

I was planning on injecting? a signal at the antenna and looking at the levels in the legs that connect to ADC Fwd and ADC Rev.

Any hints would be great. I looked through the ops manual and didn't see any settings that would? cause this.? It appears as shorted rf input, but I haven't found anything like a solder bridge.

Kindest regards,
Tim
W8TWF

Hi Tim,

There are many possibilities.? Is it low on all bands or only one?? It could be that the TR MOSFET (Q508) is not working.? Are you getting good sideband separation using the audio sweeps?? Are the values of the RF sweeps at the FT8 frequency above -10?

The most common problem is a poor solder joint on one of the toroids.

73
Evan
AC9TU

Tim: what are you comparing the QMX receiver against? HF conditions right now are not good. Do you have another known working receiver with an antenna switch?

Thanks for your inputs, but I've found and fixed it.

Somehow I mis-made the T507.? I made a full turn on the 1 turn loops.? Put it right and the sensitivity is great.

Thanks Again!!!

Great radio - now for testing transmitter. :)

Tim W8TWF