[Gonset] G-76

[radioman]

40 watts output might be about right.

several things can cause negative modulation:

1. lack of sufficient grid drive to the final amplifier... this is
critical.

2. improper loading

3. poor line or power supply regulation.


Now since you cannot obtain the proper dip on 80.. I suggest you try
looking at the modulation on other bands.  Perhaps this is a problem
with a fixed loading capactior ( or it's value).  Try using a tuner.

If the AC line voltage has poor regulation  ( lights dim when you key
transmitter or modulate)... or if the filter caps in the power supply
are old or too small...
you can see this problem..but the power supply is the least likely.

Generally, it is safe to say that the grid drive has to be advanced AT
LEAST to the point where increasing grid drive has no effect on the
output..and generally somewhat higher.  You want to achieve +ACI-grid
saturation+ACI- without exceeding the grid drive rating of the tube.

When in doubt, read the manual.

Sweep tubes are notorious for not taking kindly to long periods of tune
up.
Final Tubes with poor emission could also cause your trouble.

You can try reversing the plate leads on your modulator tubes..to
achieve better phasing.. but doubt it will help in this case.

Larry W6Wuh