[Central-Electronics] CE 458 VFO Output Level

[Robert Nickels]

On 5/22/2019 6:48 AM, Paul Christensen wrote:
> Can anyone confirm what reasonable levels to expect from the 458 VFO?

Paul -

Indirectly at least...when feeding the 20A with an external VFO I found 
the note of "8 volts peak RF" on the schematic to be pretty much right 
for 80 and 20 meters.  That would be 16 volts peak-to-peak or about 5.6 
volts RMS for full output.   The output of the 20A is definitely 
proportional to the VFO voltage and while I didn't try 40 and other 
bands extensively I did find that more VFO signal was required for 40 
than for 80 and 20 meters.   I suspect this was not an issue because 
early SSB was primarily on 80 and 20 meters, and because most hams used 
the 20A to drive a linear which may have had sufficient gain that full 
output from the excite may not have been required.

I'm not sure how you're measuring it, but .5 volts is definitely too 
low, and 3 volts peak would still be insufficient to produce full output 
on the best bands (80/20).  If you have a way to put an 8 volt peak 
signal at the right frequency for 40 meters into the 20A that would 
provide a point of comparison.

73, Bob W9RAN