Message-ID: <004c01bfbe61$552ed160$0600a8c0@MARC>
From: "mv tsi" <mv.tsi@laposte.net>
To: rsgb_lf_group@blacksheep.org
References: <09e401bfbc0e$5e55ab60$2301a8c0@maly.cz.gmc.net>
Subject: LF: Re: Optimal width for LF?
Date: Mon, 15 May 2000 13:32:50 +0200
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Hello petr,
I am interested to make a receiver.
But what technology can you use for hight stability frequency?
VFO,DDS?
My first receiver used a 3Mhz VFO and a IF at 11Mhz.
(I had a 137Khz 14 Mhz converter).
I had some probleme to have a narrow band pass with 5 cristals (800Hz).
For reduct audio band pass I used a MF10.
But with this receiver I couldn't survey a frequency during more hours.
The VFO stability had  no perfect.
73 marc.
----- Original Message -----
From: Petr Maly <p.maly@gmc.net>
To: 136 group <rsgb_lf_group@blacksheep.org>
Sent: Friday, May 12, 2000 2:34 PM
Subject: LF: Optimal width for LF?


> 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
>
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