[Boatanchors] Cheap & Easy Selectivity

[Carl]

Sounds a bit like the 8 tube super in the first edition 1942 ARRL HB and 
possibly earlier.

Carl
KM1H

----- Original Message ----- 
From: "Ian Wilson" <ianmwilson73 at gmail.com>
To: "Boatanchors" <boatanchors at mailman.qth.net>
Sent: Thursday, August 20, 2009 11:55 AM
Subject: Re: [Boatanchors] Cheap & Easy Selectivity


> Ed, thanks for pointing this out. I'd noticed the Super-Gainer before in 
> the
> early Radio Handbooks, but had never really studied it.
>
> The lineup is like this:
>  - pentode RF amplifier/mixer with regeneration to improve 
> gain/selectivity
>  - triode heterodyne oscillator
>  - 456kc IF transformer
>  - triode detector with cathode regeneration
>  - triode audio amplifier stage
>
> Regeneration in the RF amplifier is by feedback from the cathode to a tap 
> on
> the coil (like a Hartley oscillator). The level is controlled by
> varying the screen
> voltage. LO injection is to the suppressor grid of the pentode.
>
> Regeneration in the detector stage is obtained by lifting the bottom end 
> of the
> secondary of the IFT (connected to the detector cathode by a bypassed 
> resistor)
> from RF ground. This is done with a potentiometer with an RFC across it.
>
> This is a pretty nice design, with the regenerative detector being
> isolated from the
> antenna.
>
> 73, ian K3IMW
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