>
> >From: T. A. Russell, n4kg@juno.com
> >To: Rich Measures , measures@vc.net
> >
> >Rich -
> >
> >Why not just use the 20M position on 30M?
> >
> >Works like a champ on SB 220's.
> >
> >73, Tom
>
> I tried this in my SB-220, and it does work---well, sort of. The tank Q
> runs about 40% higher on 30m than it does on 20m. More Q means more RF
> circulating I burden in the bandswitch contacts. [Circulating current is
> roughly equal to Q*I-anode] Since P=I^2*R, a 40% increase in I Doubles
> the power dissipated in the contacts. However, as the bandswitch
> contacts heat, their RF-R increases, which further increases the power
> dissipated in the contacts, which further increases RF-R, which........on
> and on. OTOH, in the SB-220 design, cooling airflow is directed at the
> bandswitch.
> Rich---posted to [AMPS], e-mailed to Tom---
>
> R. L. Measures, 805-386-3734, AG6K
>
I haven't tried my SB220 on 30meters since 200 watts is all
we can run and my rig already produces that. (Can we run
over 200 now on 30meters????) I found the 4cx400 conversion
article on the mla2500 interesting since it gave full power
tests on 30meters????
--
73 Robert W5AJ w5robert@blkbox.com
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