RTTY
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[RTTY] Bandwidth of a RTTY signal

To: <rtty@contesting.com>
Subject: [RTTY] Bandwidth of a RTTY signal
From: vk4cej@hamsnet.net (John)
Date: Wed, 29 Aug 2001 18:56:02 +1000
Michael, K1JE said (in part)
> When I first started with RTTY over 20 years ago, we used active filters
> composed of cascaded op-amp circuits (741's worked well). Mark and space
> had separate filters, each 80 Hz wide (nominal). I think most sound-card
> based RTTY decoders emulate this type of filter, we just don't see this
> detail usually. The radio's filters are merely another IF in the
processing
> chain, with more or less limited selectivity.


My first RTTY demod. was a device that ANARTS put out in kit form and was
called a DT-600.  The filters consisted of wire wound 'pot cores'. It was
connected up to an old Siemens paper chewer and I used paper tapes to send
out CQ's and other monotonous stuff.....  I built mine in the early 1980's
and I still have it..  Unfortunately, I have long ago lost the schematics
and hook-up information for it.. If anyone had or has one of these devices
and is currently using it in conjunction with a computer, I would love some
info on it....

John - vk4cej


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