[Drake] Re: SW-4A Accessory Socket (Garey Barrell)

[Garey Barrell]

Ron -

Jim was mistaken about the audio amp part.   The connections are B+, 
Fil, Ant and Ground.  These connections are the same on all of the 2 and 
4 Series receivers.

There were Preselectors, and in fact they are still being offered by 
several manufacturers.  Essentially a preamplifier combined with a 
tunable, relatively narrow filter.  They were originally added to older, 
single conversion receivers to give a little more (hopefully low noise) 
gain on the higher bands, and additional front end selectivity to combat 
images.  Kind of like the front end of a Drake receiver!  :-)

Preamps were also fairly popular, since many older receivers rapidly ran 
out of sensitivity on 15 and 10M.

The 2A/2B used this connector for the 2-LF Low Frequency Converter, but 
was normally used for the accessory 100 kHz calibrator.   The 4-LF was 
for the 4 Series receivers.

The same connections were also usable for VHF/UHF converters.

Back in the "Old Days", similar external power connectors were used for 
100 kHz calibrators, electronic T-R switches, preselectors, preamps, 
converters, etc., etc.  

73, Garey - K4OAH
Atlanta


Ron Wagner wrote:

> Jim, Gary,
> Were not things call pre-selectors popular around the time of the 
> SW-4A? The things that were an antenna preamp and tuner kind of 
> thing.  Sounds like the exact fit to run a tube voltage wise, and the 
> antenna input would be for the output of the preamp/tuner.  Not sure 
> what the audio input would be for though.
>
>>
>>> It didn't need it, since it goes down to 200kc out of the box. BTW, the
>>> socket taps the 120vdc, 6.3vac lines and the antenna input and input 
>>> to the
>>> audio amp.
>>> Jim
>>> WA8SDF
>>
>
> 73,
> Ron
>
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> Amateur Radio Station: WD8SBB - Ron  and  KB8NRP - Joann
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