My just completed #4438 with SSB, DSP, 160M, and 100Watt Modules
seems to be working just fine .... except:
.. on the low end of 80 meters (3500-3700 approximatly) the signal
sounds like there is a 'ringing' on it when listening to another
receiver in the shack. This happens only at power levels above about
50 watts and only on the low end of 80 meters.
Here is what I have done:
Replaced my power supply with a large lead-acid car battery to
eliminate any possibility of interaction with the power supply.
Results the same with either power source.
Tried two different monitoring receivers ... same results with each.
I am using a 50 ohm dummy load (Heath Cantenna).
This is what I see:
A scope looking at the RF waveform shows NO am modulation. The
envelope is clean.
A scope looking at the RF waveform does show a slight blurriness in
the horizontal axis indicating rapid but slight frequency shift.
A scope monitoring the 12 volt input shows a small sinusoid waveform
on the 12 volt input (a hundred mV or so) indicating that there is a
significant AC component of current being drawn from the battery. The
frequency of this AC component of input current is about 30 hertz.
I suspect ALC instability of some kind. I could sure use some help
here.
Don K7FJ
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