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R: Replacing receiver filters for 38k4 reception



Hi Pop, VU2POP

Wath news about VUSAT ?

Apparently the AMSAT-India site is down.

73" de

i8CVS Domenico

----- Original Message -----
From: A.R Pratap Kumar <comex@vsnl.com>
To: <amsat-bb@amsat.org>
Sent: Wednesday, March 30, 2005 5:58 AM
Subject: Re: [amsat-bb] Replacing receiver filters for 38k4 reception


> Hi Douglas
> The CFW 455E is the NBFM type filter 15 Khz mostly black color, you can
> replace it with a CF455B which is Orange in color mostly used in Broadcast
> FM radios it has a bandwidth of maybe 75 khz or more should be available
in
> most electonic shops.
> If you dont get it ask me I can put in a airmail cover to you.
> Good luck
> Best 73
> Pop
> VU2POP
> Amsat India
>
>
> ----- Original Message -----
> From: <Dquagliana@aol.com>
> To: <amsat-bb@amsat.org>
> Sent: Monday, March 28, 2005 2:29 AM
> Subject: [amsat-bb] Replacing receiver filters for 38k4 reception
>
>
> > I have an FM receiver kit that I'd like to
> > modify for 38k4 reception from Echo. I need
> > to make the bandwidth of the receiver wider
> > in order to pass the 38k4 signal to the modem.
> > According to the handy G3RUH reference at
> >
> > http://www.amsat.org/amsat/articles/g3ruh/109a.txt
> >
> > I need about 60 kHz bandwidth at the IF to
> > pass a 38k4 signal.
> >
> > The first filter in the receiver is just a
> > single crystal, which I think I can leave in
> > the circuit as is.
> >
> > The second filter (FL2) in the receiver is,
> > I think, a CFW455E, which has a bandwidth of
> > about 15 kHz. This is too narrow for 38k4.
> >
> > Since this is a "no budget" ham radio project,
> > can I get something that works if I replace the
> > CFW455E filter with 0.001 uF capacitors? I'm
> > not exactly sure how to do this since the
> > filter has *three* pins.
> >
> > Suggestions? Has anyone already done this?
> >
> > Douglas KA2UPW
> > ----
> > Sent via amsat-bb@amsat.org. Opinions expressed are those of the author.
> > Not an AMSAT member? Join now to support the amateur satellite program!
> > To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org
> ----
> Sent via amsat-bb@amsat.org. Opinions expressed are those of the author.
> Not an AMSAT member? Join now to support the amateur satellite program!
> To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org
----
Sent via amsat-bb@amsat.org. Opinions expressed are those of the author.
Not an AMSAT member? Join now to support the amateur satellite program!
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