[HBR] WARC bands?

[Ian Wilson]

Hi Walt,

Good points. I have been working for a number of years on
something based on the 75S3 architecture (this project sprang
into existence when I acquired a PTO for $0 at a swap meet.
(It works flawlessly, of course).

Despite occasional successes, this is still far from a usable
receiver. If I had spent the time building an HBR I have no doubt
that I would have had a functional receiver long before now.

I am very glad that this group exists - I have derived much
useful information from it over the past few years.

73, ian K3IMW


On Mon, Nov 10, 2014 at 5:05 AM, Walt Hutchens <waltah at earthlink.net> wrote:

> Ian said:
>
> > I  think that one problem with the crystal-controlled converter
> > in front of a tunable IF is that you may decide to adopt that
> > architecture instead of the HBR! - worked pretty well for Collins,
> > after all.
>
> It worked very well for Collins but no receiver using this
> architecture could be called 'simple' or 'easily duplicated by a ham
> with modest skills.'
>
> The Collins receivers mostly used two or three two IFs, at least one
> of them tunable. Often one IF was either shifted or omitted on some
> bands. Multiple conversions (and sometimes a varying number of
> conversions) make these sets very difficult to design for a strong
> signal environment like the ham bands. Collins did it, all right, but
> they went out of business because they could never recover the cost of
> the engineering.
>
> Never say 'never': There may be situations where a crystal controlled
> converter ahead of an HBR is the way to go -- perhaps you're not the
> builder of the HBR and you can't do that sort of coil winding: The
> coils for a converter ARE simpler, since they usually aren't expected
> to deliver any selectivity. And specific coil data will be included
> with any description of such a converter.
>
> Converter design is a thing unto itself and if one wants to learn
> about it, this might be a good way to go. Equal performance (to just
> winding the WARC coils) will be tricky but that could be part of the
> fun.
>
> Walt
> KJ4KV
>
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