Follow-up on success of getting my FT-990
down to or below 5 watts output.
I have abandoned the Ext ALC attempt to
control power output. When a plug in inserted
into the Ext ALC jack, it over rides the RF power
control. I was not able to get the voltage setting,
about -3.55 volts, stable enough to be practical
in my situation.
I am continuing with a pi-network resistor
attentuator. The first one I built was for 3 db cut,
and worked fairly well. It actually reduced the
power to about 4 watts. I have tested a 1.5 db
cut network and it reduced power to about 6
watts. I plan on making a minor change in
resistance for about a 2 db cut and 5 watts out.
The network is not switched out during receive,
but doesn't seem to make that much difference.
One question: Has anyone run the FT-990 on
deep-cycle battery power? I have a 90 amp-hr
marine battery when fully charged has a voltage
of about 12.7. I want to use the battery to run
QRP power levels. Any one with experience?
The manual says 13.1 to 15.2 volts.
Do they really mean it? Thanks,
and hope the above is of some interest.
73,
Darryl, KK5IB
out
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