Collins also recommended that a specific length of feedline should be used
between the exciter and the 30S1 input. I have ignored this warning with no
ill effects. The 30S1 uses a 4CX1000A in the final.
73, Joe
Tom Rauch wrote:
> > The 30L-1 does not have neutralized tubes, so apparently 811A'a do not
> > absolutely require it.
>
> If the 30L1 had neutralization, Collins would not have to have a
> series of stability modifications to that amp. The amp also would
> be stable if the load was removed from the input and output, which
> it is not (as produced).
>
> They also would not have to tell people to use a certain length line
> between the exciter and PA.
>
> ALL four 811A amplifiers need neutralized above 20 MHz for
> stability when operated at normal voltages. The only exception
> would be if there somehow was some "accidental" feedback added
> to cancel feedthrough inside the tubes.
>
> 73, Tom W8JI
> w8ji@contesting.com
>
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