Fw: AM Crystal filter for SB-303

[Eddy Swynar]

Yes, the large-sized SSB filter from the SB-300 that I took apart did,
indeed, have a micro-mini toroid as part of the L/C network therein---but
there was also a super-small mini ceramic trimmer there, too...

The smaller-sized SSB filter that I dis-assembled (SB-301) had what looked
like a couple of transistor radio-sized IF cans inside it.

In any event, I would recommend simply swapping out four of the crystals
with new ones cut for the AM bandwidth. PERIOD. The extra two other crystals
in the SSB filter can be removed as well, as the AM filter utilizes but 4
crystals in total.

~73~ Eddy VE3CUI - VE3XZ



----- Original Message -----
From: "w1id" <w1id at fcgnetworks.net>
To: "Eddy Swynar" <gswynar at DURHAM.NET>; <HEATH at LISTSERV.TEMPE.GOV>
Sent: Wednesday, February 28, 2001 1:26 PM
Subject: Re: Fw: AM Crystal filter for SB-303


> On Tuesday, February 27, 2001 at 08:07:16 PM, Eddy Swynar wrote:
>
> > Hi All...
> >
> > Can anyone reading this tell Larry if the SB-301 type IF filters are
directly interchangeable (sp?) with those used in the newer SB-303...?
> ---------------------------------------------------------------
> They are all interchangable, all the same impedance and characteristics.
You can mix and match as long as they are all the same size. Other than
that, you'd have to drill holes to make thme fit, but then again, they'd
still work. As far as building or homebrewing a 5KHz AM filter is concerned,
I've opened up one of my excess SSB filters and didn't see an adjustable
coil. Only saw a fixed, multifilar toroid inductor. It probably reads close
to what the author of the AM filter post was talking about. No big deal.
I've been wanting to build one but have been sidetracked by other projects.
Seems like the Jan Crystals option would be a good way to start instead of
having to pay $110, which is more than I paid for my SB-300/401 twins and
about twice what I paid for my SB-303. I know Inrad used to sell those
filters a long time ago so they must still have the "receipe" somewhere.
> w1id
> e-mail: w1id at fcgnetworks.net
>
>
>
>

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