Antonio Vernucci wrote:
With that sucker, delivering a stiff 1200 or 1300 volts on the
MOPA's final VT-4C,
it's plates would turn a soft red blush on long dashes..... and would
work anyone
you could hear!
Old Chief Lynn

Thanks for info,

I have no problem at all with the dynamotor, as I power it using a
stabilized computer mainframe power supply that easily delivers 100A
with no voltage drop at all.

But the dynamotor is too noisy; moreoverr it becomes fairly hot if kept
running for long periods.

Yes, the solution of using a resonant.choke power supply is probably the
most appropriate for obtaining a stable HV, but it is not easy to find a
suitable choke. Will see what I can do.

73

Tony I0JX

Tony, I wrote up a mod I came up with for Electric Radio, last year.
I'll send you the diagram for it if you'd like. Essentially, it moves
the filament 24v from the output side of the power contactor (inside the
dynamotor relay box, on top) and moves it to the input side. That way,
the filaments light up and gets things warmed up whenever power is
applied. When you want to xmit, just hit the power switch. When you're
done turn the switch off. My next trick will be to route PTT to an
external relay which will both key the transmitter and turn on the
dynamotor (paralleling the front panel power switch). When PTT is
released, the dynamotor stops. That way, no duty cycle problems arise.
Note also that in the manual, it says that the duty cycle of the
dynamotor is about 30 minutes, and that is at altitude. At room temp, I
figure one has about 15 minutes before things bad happen. The book also
says for ground maintenance activity, remove the dynamotor end bells for
cooling. Unlike the ART-13 and similar heavy-duty dynamotors, there is
no throughput cooling blower on the PE-73 or BD-77.

Regards Jeep/K3HVG



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