The RF gain control does indeed control the RF stage on the 2B.
If you have problems with overload on those receivers you most likely have a
leaky capacitor somewhere in the AGC circuit or a tube with grid to cathode
leakage.
the AGC or AVC as they call it, is a very high impedance circuit and any
slight leakage screws up the whole thing. You can not even put a high
impedance voltmeter or VTVM anywhere on the AGC line as it will load it
down.
I have all 3 of the early drake receivers, the 1A, 2A and 2B. They all
operate similar. In most cases if the AGC is working properly you never have
to touch the RF gain control. Just leave it wide open and everything works
fine.
The Drake 1A actually has better dial calibration the 2 series even though
the 2 has the calibrated? Dial escuson which in my opinion is about useless.
You can interpolate the dial on the 1A better than on the 2.
Sensitivity is great but selectivity is not great. The nose of the filters
are pretty good but skirt selectivity is not good. A strong adjacent
frequency will eat it up.
The 2A is actually the best receiver for SW listening as the AM filter is
wider on it than on the 2B. the 2B is next to unusable on AM as it is too
narrow.
73
Gary K4FMX
> -----Original Message-----
> From: amps-bounces@contesting.com [mailto:amps-bounces@contesting.com]
> On Behalf Of k7fm
> Sent: Sunday, June 05, 2011 9:38 AM
> Cc: amps@contesting.com
> Subject: Re: [Amps] FW: [Boatanchors] Best Boatanchor 160-
> 10mReceiversforSSB?
>
> The Drake 2B has a serious design flaw. The rf gain control does not
> reduce
> gain of the rf amplifier tube, and as Carl said, it overloads severely.
> If
> the radio overloads, turning down the rf gain has no effect. I had a
> neighbor running legal limit that tore the 2B up. I removed the rf gain
> control and left it fixed at maximum gain, then installed a switchable
> attenuator in the hole. That solved the problem.
>
> And, to keep this amp related, the problem only occurred when he had his
> amp
> running - there, I complied.
>
> 73, Colin K7FM
>
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