[AMPS] 8877 efficiency

[Steve Katz]

I doubt it's the tube, Alfredo.  You didn't describe the circuitry, but it
sounds as though your 3CX800 amp is 20% more efficient than your 8877 amp!
I built an 8877 for 144 MHz that provided ~60% efficiency, that is 2500Wdc
input for 1500W RF output, using slightly higher Ep than you (4kV), but had
to experiment quite a lot to even allow this efficiency.  For one, I had to
change chassis dimensions (!) because the first chassis used had some weird
resonance that would not allow the plate tank circuit to tune well; going to
a 2" wider chassis helped a lot.  Isn't VHF fun?

WB2WIK/6

"Each success only buys an admission ticket to a more difficult problem." --
Henry Kissinger

> -----Original Message-----
> From:	Alfredo Rosati I5UXJ [SMTP:alfredo@cln.it]
> Sent:	Monday, November 19, 2001 3:26 PM
> To:	amps@contesting.com
> Subject:	[AMPS] 8877 efficiency
> 
> 
> i have an 8877 in 2 meter 
> with 50 watt input
> 3700 volt  700 ma  50ma grid
> i have in output only 1250 watt.
> if the input is 100 watt i have 2000 watt but 1,1 Amp and grid 120ma.
> 
> i have an 3cx800 that with 40watt input 3100 volt 650ma put 1400 watt
> output.
> 
> is my 8877 defective????
> how much power in your 8877 amplifier in two meter you obtain ??
> hello i5uxj
> 
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