[HBR] Use of single 1610 kcs transformer?

[Peter Bertini]

I'm planning on using some 1682 kHz half-lattice crystal filters from
defunct Heath HR-10 receivers in my HBR, when I have time to start it. I'll
be using  a 1682 kHz IF, with three sets of the Heath filters in the first
IF right after the first mixer. The IFTs will be reworked units salvaged
from defunct Command WWII surplus receivers.  That will protect the second
mixer from any signals that are more than a few kHz off channel.

Pete

On Sun, May 16, 2010 at 10:19 AM, Edward Swynar <gswynar at durham.net> wrote:

> Hi Cal,
>
> Being rather ignorant of the actual specifics of the HBR (I confess!), I am
> wondering if there is any sort of crystal IF filter ahead of the 1600-KHz
> IF
> chain...?
>
> If so, you're in luck: simply emulate what the Heathkit designers did with
> the SB-300 series of receivers, i.e. they had the crystal IF filter FIRST
> in
> the chain, & used NO IF "transformers" as such at all, but rather, a couple
> of simple L/C paralleled circuits between stages---the selectivity was
> afforded early-on, by way the crystal filter.
>
> It works!
>
> ~73~ de Eddy VE3CUI - VE3XZ
>
>
> **************************************
>
> ----- Original Message -----
> From: "C Eus" <catman351 at gmail.com>
> To: <hbr at mailman.qth.net>
> Sent: Sunday, May 16, 2010 10:04 AM
> Subject: [HBR] Use of single 1610 kcs transformer?
>
>
> > All:
> > I only have access to one genuine 1600 kcs IF transformer.  I do not have
> > access to a second to emulate any of the HBR 1600 kcs dual IF transformer
> > configurations.  What would be the "penalty" for not conforming to this
> > configuration?  Obviously, selectivity issues may crop up.  However, I
> plan
> > on maintaining the triple 100 kcs IF transformer chain ala the W6SAI
> "deluxe
> > HBR" plan.  Looking for more comments/suggestions on this portion of the
> > project.
> >
> > FYI, I just took a look at Jay Helm's IF strip set up.  Looks "kewl."
> > However, my strip should be a little thinner.  The nice thing about the
> HBR
> > set up is one can, within reason, articulate a reasonable variation to
> suit
> > one's tastes.
> >
> > Cal, N6KYR/4
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