[Amps] 30L1 Tuning

[rlm]

On Sunday, November 2, 2003, at 09:48  AM, RFlabnotes at aol.com wrote:

> I have an old 30L1, which has been in and out of use here for some 
> time. It
> has also been the cite of several interesting ( and not always 
> successful!)
> enhancements. I found it quite easy to modify the meter circuitry to 
> read grid
> current, in place of the infamous 'TUNE' position. This, along with a 
> wattmeter
> in the feedline, makes it possible to quickly and easily get it 
> optimized at
> full output without hosing the 811A (or 572) grids.

***  The problem is not with the 811A grids, it's melting holes in the 
811A plates/anodes due to the increased velocity of electrons because 
Collins Radio used more than the rated anode V.

>  If you are interested, drop
> me a line and I will send a copy of the page in my lab notebook which
> documents this, as well as data for conversion to 572's for 1KW+ 
> output.

***  Eric -- T160L/572Bs and 811As use the same filament, and therefore 
have the same peak emissive ability.  For SSB, up to c. 1800VDC, there 
is no difference in PEP output between an 811A and a 572B.  The 
advantage of a 572B is that its graphite anode  is good for 2400VDC, a 
potential that will easily damage the thin metal anode of an 811A.
>
> Eric von Valtier K8LV
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>
Rich Measures, AG6K, 805.386.3734.  www.somis.org/