[Amps] Initial RF testing of 4CX1000A amplifier

[Vic Rosenthal]

Forgot to add that screen voltage was 325, tightly regulated by GM3SEK tetrode board.

Vic

> On Nov 4, 2013, at 9:40 PM, Vic K2VCO <k2vco.vic at gmail.com> wrote:
> 
> After fixing various stupid mistakes (including mislabeling input and output connectors -- really!) I applied some RF drive to my new amplifier for the first time tonight.
> 
> In order to stay out of trouble, I drove it with my QRP K2. Here are the results on 40 meters:
> 
> Drive = 13 W
> Ep = 3200 V
> Ip = 450 mA
> Po = 760 W
> Ig1 = 0
> Ig2 < -10 mA (off scale on the bottom of my meter, which only goes down to -10)
> 
> Bias was adjusted for zero-signal current of 250 mA.
> 
> The overall efficiency was 52%, which I think is good considering that the plate impedance comes out to about twice the design value.
> 
> I am not sure the large negative screen current is normal with these conditions. What do you folks think?
> -- 
> Vic, K2VCO
> Fresno CA
> http://www.qsl.net/k2vco/