[HBR] HB 67 Receiver Introduction

[Diane Swynar]

Hi Jim...

Yes, that's quite a neat circuit and well worth looking into...

The designer's philosophy was to make the front end completely "bullet
proof" in the matter of selectivity---and that's ALL selectivity, i.e. both
immunity from the Novice keying his rig directly across the street from
you, as well as from junk on parts of the band slipping past the front ends
of less robust rigs.

He really did a job of it, too, with that "quad" set-up of L/C networks!
The grounded grid RF amplifier was put in place strictly to compensate for
circuit losses therein.

If one were to forgo the mechanical filter, conventional IF transformers
would be an absolute must in the IF chain...have you ever shorted out the
IF filter in an SB-301 to see what its effect might be on selectivity?
(Heath used a similar scheme). It'd be BROADER than any barn door you could
find!

That heterodyne nulling circuit would be a worthwhile addition to the HB-67
as well--simple, but effective, according to the author.

I don't know that the average Ham would really need all that elaborate a
front end, but as you say, the piece is full of good ideas & thought
starters!

~73~ Eddy VE3CUI - VE3XZ





> Just a quick note....
>
> Besides the "Miser's Dream", Squires and Goodman articles, there is one
> more  "must read". QST for February, 1972 has an article titled "An
> Experimental  Receiver For 75 Meter DX Work" by Doug Blakeslee, W1KLK
> (SK).
>
> This receiver is very similar to what Cliff wants to build. It uses
> four  tuned circuits before the mixer, and a low-gain grounded-grid RF
> stage. Mixer  is a single-ended 7360. The IF is 455 kHz, based on a
> Collins mechanical  filter. Lots of good circuits, as well as design
> philosophy and layout ideas.
>
> More to follow but I'm out of time
>
> 73 de Jim, N2EY
>
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