[HBR] IF cans for HBR

[David Richards]

 Four tuned circuits operating at 1600-1700kc  should ensure that only a reasonably small slice of frequencies could cause problems before the highly selective elements at the lower IF come into play. Use of strong mixing stages and holding  pre-selectivity gain to 'just enough' to comfortably compensate for losses should eliminate the need for a  crystal filter at the first IF.  If this caveat is observed, the '59 approach will work very well. For tough, 'close-in' band-crowding conditions, a peaking Q-multiplier constructed to operate at the first I.F. can be very helpful; especially on cw, and is a much simpler and less restrictive
approach. DSR

--- On Fri, 9/19/08, Peter Bertini <radioconnection at gmail.com> wrote:

From: Peter Bertini <radioconnection at gmail.com>
Subject: Re: [HBR] IF cans for HBR
To: "HBR Receiver List" <hbr at mailman.qth.net>
Date: Friday, September 19, 2008, 12:46 PM

Absolutely!

The W6TC receivers are based on technology that was state of the art in 1959.

One of the points is having the bulk of the selectivity after three stages with
significant gain: RF amplifier, and the two mixers!

The HR-10 offers some excellent possibilities,
in my humble opinion, to bring the HBR's performance up a notch or two.

I'd use the half-lattice crystal filter section from the
HR-10 and  use in the HBR circuit.  It is a modest filter, but
it will give the second mixer greater protection to strong signals to
out of passband
signals than is offered by LC filtering alone.

The 85kc IF will still provide the bulk of the selectivity and
receiver IF passband
shape factor, and the 1600kc IF transformer will provide the needed
filtering for
any spurious responses in the half-lattice filter stop band.

I' ve been looking for a junker HR-10 to raid the filter crystals
from!  If you don't
use them, I'd be interested in buying them :)

One other possibly usable part is the tuning cap, I'm not sure what the
range is, but it might be usable if removing a plate or two will bring the
minimum and maximum capacity close to that of the Millen part used in the
original HBR.  Regardless, most subs are going to require some
needed rework of the original coils.

Pete

On Fri, Sep 19, 2008 at 4:03 AM, Clarence Peckham
<cpeckham at mindspring.com> wrote:
> Good morning,
>
> I am new to the list and have question. Is anyone using the parts form a
> heath HR10 to make an HBE? I noticed that the IF frequency is almost the
> same so a lot of the parts should be usable right?
>
> Thanks,
>
> Clarence, NT7V
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************************************
Visit the HBR Receiver Web Site with over 100 pictures of receivers and 
construction notes...... via http://www.qsl.net/k5bcq/ 
there is also a mirror (faster response)at http://k5bcq.edebris.com/
 

Retrieve reflector archived data via
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