[ARC5] Receiver sensitivity

[Kenneth G. Gordon]

On 10 Dec 2016 at 19:44, Jim Haynes wrote:

> I don't know how it compares with more conventional receivers, but the
> rare Squires-Sanders receiver uses a 7360 beam switching tube as a mixer.
> And as the receiver front end - no RF amplifiers ahead of it.  Squires
> wrote an article "A New Approach to Receiver Front-End Design" in QST
> for September 1963.  Review of the receiver in QST for May 1964.
> 
> The same front end was adopted by Vic Poor for the receivers made by
> Frederick Electronics Corp. for commercial/government use back in
> those days.  His receivers were all solid state except for the 7360
> mixer front end.

And I have a VERY interesting receiver here which was at one time used by the FBI, God 
alone knows where. It uses pie-shaped devices in which are mounted separate tuned 
circuits for the input and oscillator sides on a rotary "band-switch" mechanism. The input 
stage is a straight mixer. No RF amp.

I, very strangely, s finally offered a manual for this thing by someone attached to this forum, 
who found the manual...in a dump in New York...

All other receivers of this type had had the input tuned circuits destroyed by the FBI to 
preclude "others" from figuring out what frequencies they were using.

Mine is substantially complete.

I'll have to go look at it to give you the model number and maker.

It is a VERY innersting receiver. ;-)

Then, of course, there is the so-called "Pullen Mixer"...

Ken W7EKB

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