Cecil Acuff wrote:
> What causes output tank efficiency to change when voltage/current changes?
>
> My Clipperton L, which has been reworked somewhat, takes a nose dive in
> efficiency when tuned in the SSB position as opposed to the CW.
>
> CW= Slightly over 1500V loaded to 750ma with 800W output for around 70%.
>
> SSB= 2250V loaded to 975ma with 1050W output for a poor 48%.
>
> This testing was done on the 17m band into a Bird load.
>
> Where am I loosing 400 or so watts? Is this just a limitation in RF current
> capacity of the Tank coils or is there something else at play that I just
> don't understand at this point.
>
I'd pretty much expect to see this drop in efficiency on 17.
Also, IIRC the voltages are such you will get maximum efficency by
tuning up in the CW position and then switching to SSB. It's been quite
a while but as I recall plate voltage regulation in these is not the best.
Also look out for resonances in the plate choke.
73
Roger (K8RI)
> Additional info:
>
> Power supply caps have been replaced.
> Tank coils have been rewound to improve 160M operation from #6 copper and
> #12 (close spaced in teflon tubing) for the 160/80 section all silver
> plated. Flat copper strip from the bandswitch to the coils all silver
> plated as well.
> LDG auto tuned input board mounted internally.
> Raytheon tubes.
> Amp running on 220vac
>
> Not trying to make a legal limit amp out of it but trying to better
> understand the workings of the output tank...
>
> Thanks in advance..for helping me to understand what is probably elementry
> to most.
>
> Cecil Acuff
> K5DL
>
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