[Boatanchors] Receiver questions

[Dave Brown]

For info on some top end rxs check out the premium-rx site.
73
Dave
 ZL3FJ


----- Original Message ----- 
From: "Ian Wilson" <ianmwilson73 at gmail.com>
To: <boatanchors at mailman.qth.net>
Sent: Friday, December 17, 2010 6:16 AM
Subject: [Boatanchors] Receiver questions


>I was using a Drake 2-B this morning. This receiver has some very 
>nice
> things about it
> (the preselector, and the variable IF bandwidths). On the other 
> hand, the
> product detector
> isn't very strong, and I imagine that front end large signal 
> handling is
> moderate.
>
> In the 3-30MHz range, what receiver(s) has(ve) the "best" (CW and 
> SSB,
> primarily):
>  - performance in the presence of large adjacent interferers?
>  - product detector?
>  - legibility?
>  - audio?
>  - AGC?
>  - product detector?
>
> Using tube-only technology, it seems to me that the best 
> architecture for an
> HF receiver would
> be something like the Squires-Saunders(sp?) SS1:
>  - no RF amplifier
>  - beam deflection mixer (single conversion)
>  - crystal filter immediately following the mixer
>  - frame grid IF amplifier tubes (e.g. 6EH7)
>  - beam deflection product detector(?)
>
> Questions:
>  - IF- or audio-derived AGC?
>  - audio? (Single-ended triode for AM? <g>)
>  - single conversion means problems with oscillator stability, or
> difficulties
>    with birdies if using heterodyne schemes. Double conversion is 
> much
> easier
>    but significantly weakens the front end performance. What to do?
>  - how useful are audio CW filters?
>
> I would like to look at real circuits, so observations about 
> receivers for
> which
> schematics are readily accessible would be helpful.
>
> 73, ian K3IMW
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