In message <3.0.1.32.19980610090421.00a51750@mail.rcru.rl.ac.uk>, Mike
Willis <m.j.willis@rl.ac.uk> writes
>
>I have now got an AM6155 running on 432MHz using the W3RJW
>mods to the RF cavity (need a new blower BTW) but although
>I get 300mA of anode current from a few watts of drive, I can
>not get more than 100W output. More drive starts to affect the
>grid biasing and leads to excessive screen current. This is with
>100mA standing bias. I expected 40% efficiency, not 15%.
>
>I have tried all positions of the loading capacitor. The tune dial
>reads 151-155 at peak output, depending to some extent on the loading.
It reads as if the anode load impedance is way too low.
>
>Is is possible that the tarnish on the silver plating is to blame
>for this or might there be some other reason?
I doubt it - one reason for using silver is that silver oxide is a
conductor, albeit not as good as the pure thing.
Steve
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