I show very little grid current. Roughly 3000 volts .500 mill of plate
current 1500 in 200 out. 20-25 watts drive Ft736 driver. Mike
Those readings seem ok. I would think that 20 watts would drive it to 500
ma. I would make sure that you could move the plate loading "plate" far away
from the tube. Are you sure that the plate circuit goes thru resonance?
Maybe it never does! You might check that too. Use a grid dipper or antenna
analyzer.
If the loading control has little effect, I would also try looking at the
input with some sort of return loss bridge or antenna analyzer. You could
also put a Bird 43 type instrument in and see what the VSWR looks like when
you apply drive power. I remember I had a problem with my new amplifier and
it was a poor connection on a ground on the input circuit around the tube
socket. The input impedance changes with drive level, so a VSWR check is
only valid when the amp is being driven with RF, but you should still see
some sort of poorer match with almost no drive.
Dave K1WHS
----- Original Message -----
From: "mike repinski via VHFcontesting" <vhfcontesting@contesting.com>
To: <vhfcontesting@contesting.com>
Sent: Wednesday, December 31, 2014 4:16 AM
Subject: [VHFcontesting] 222 amp
One other observation. The controls do not seem to operate as sharp as my
2 meter amplifier does. Kind of sluggish. The loading does not seem to do
much. Mike WB8PFZ
_______________________________________________
VHFcontesting mailing list
VHFcontesting@contesting.com
http://lists.contesting.com/mailman/listinfo/vhfcontesting
_______________________________________________
VHFcontesting mailing list
VHFcontesting@contesting.com
http://lists.contesting.com/mailman/listinfo/vhfcontesting
|