>km1h @ juno.com wrote:
>>On Sat, 14 Mar 98 05:44:02 -0800 Rich Measures <firstname.lastname@example.org> writes:
>>One of the "no hassle" untuned input circuits floating
>>>about recommends putting an inductor in series with the grid
>>>R to improve the 12m and 10m input SWR. Doing so is an invitation to vhf
>> If Emtron, QRO, and Alpha do not use such a circuit, Good.
>>> . However, one does not know until one sees the circuit.
>>I do not know what they or Alpha use.
>The 91B "absorbs" the input capacitance of the 4CX800As by making it act
>as C2 in a pi-network. The tube input capacitance is about 100pF total,
>and the fixed capacitors used for C1 are about the same value. Thus the
>transceiver sees a 1:1 impedance transformation into the 50-ohm
>At all HF/VHF frequencies, the grids see the 50-ohm resistor connected
>directly to ground.
If the grids are connected directly to ground, how it it possible to
deliver grid bias potential to the grids? . No neutralization? . Eimac
R. L. Measures, 805-386-3734, AG6K
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