Message-ID: <09e401bfbc0e$5e55ab60$2301a8c0@maly.cz.gmc.net>
From: "Petr Maly" <p.maly@gmc.net>
To: "136 group" <rsgb_lf_group@blacksheep.org>
Subject: LF: Optimal width for LF?
Date: Fri, 12 May 2000 14:34:08 +0200
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Hello all
I am just designing a new RX for 136 kHz band. It will have IF on 1 MHz with
high quality x-tal filter with bandwidth 200 Hz. The main selectivity will
by obtained on AF with passive filter with coils on pot cores. Till now I
used similar filter with bandwidth about 50 Hz and it seems to be still too
wide for LF. I was about to make it new with 15 Hz width. Somebody here
mentioned 1 Hz wide filter which seems to me to be too narrow. At least, the
filter cannot be narrower than obtainable osc stability. Can we make a
little questionnaire here? What bandwidth do you use and what is the
experience?

73, Petr, OK1FIG