[AMRadio] SP-600 IF Bandwith Specification


Mike Sawyer w3slk at uplink.net
Sun Oct 1 22:33:34 EDT 2006


I'm curious, how well these filters would work in lieu of the Collins 
filters? I have a 75A3 with just the 3.2 Kcs mechanical filter and it just 
plain sucks. Maybe if it had something along the lines of a 5.5~6.0 Kcs 
might make it a little more tolerable.
Mod-U-Lator,
Mike(y)
W3SLK
----- Original Message ----- 
From: "Brett gazdzinski" <brett.gazdzinski at verizonbusiness.com>
To: "'Jim Candela'" <jcandela at prodigy.net>; "'Discussion of AM Radio in the 
Amateur Service'" <amradio at mailman.qth.net>
Sent: Sunday, October 01, 2006 8:25 PM
Subject: RE: [AMRadio] SP-600 IF Bandwith Specification


Yes, the Kiwa filters are something like
5.5Kc at -6db, and 6 Kc at -60 db!

Brett
N2DTS



> -----Original Message-----
> From: amradio-bounces at mailman.qth.net
> [mailto:amradio-bounces at mailman.qth.net] On Behalf Of Jim Candela
> Sent: Sunday, October 01, 2006 7:34 PM
> To: Discussion of AM Radio in the Amateur Service
> Subject: [AMRadio] SP-600 IF Bandwith Specification
>
>
>
> I stumbled on a good mechanical filter article that goes into
> upgrading the SX-42 and SP-600. I found this pretty interesting.
>
> This is how it starts:
>
> A complaint many shortwave receiver owners have is the
> inadequate skirt selectivity in their equipment. This is not
> just a problem in old or inexpensive units. The skirt
> selectivity of even some modem, top-priced receivers is less
> than what it could be for dealing with current crowded band
> conditions. Mechanical filters are often expensive, and they
> may need accompanying resonating capacitors. Sometimes a good
> drop-in substitute filter can be found; otherwise
> installation may be difficult. Even with a new filter
> successfully in place, an insertion loss can result because
> of impedance mismatch. Such a loss, averaging 6 dB, is not
> important for strong signals, but for weak ones it makes all
> the difference in readability.
>
>
>
> http://www.kiwa.com/goodwin.htm
>
> The -6/-6OdB band widths for the SX-42 are about 4/21 kHz and
> for the SP-600J about 3/18 kHz - good in their respective
> times, but most inadequate for today's conditions.
>
> SP-600:
>
> '3' means 3.0 Khz at -6db, and 18 Khz at -60db
> '8' means 8.0 Khz at -6 db, and 26 Khz at -60db
> '13' means 13.0 Khz at -6db, and 35 Khz at -60db
>
> Jim
> JKO
>
>
>
>
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