[R-1051] CV-483 Mod Info

[AA4BR]

I once maintained URA-17s for the Navy.  Once properly aligned they were
pretty solid. The common configuration consisted of two CV-483s, which were
in turn connected to the outputs of two R-1051s for diversity.  Of course,
one CV-483 cannot provide diversity.

The mods you see are very likely the result of several field changes that
were issued for this equipment.  The trannies that handled the 60ma loop
current went through at least two changes that I can recall.  Seems like
there was an issue with a transformer in the power supply circuit that
tended to leak a tarry substance when it got good an hot as well.

Unfortunately I no longer have my marked up schematics for this gear or I
would be happy to go into more detail.

If you have no letter designation following the "CV-483" on the label plate
(such as "CV-483B/URA-17") you are looking at the original version which
should have several mods in the unit.  If I recall correctly, the CV-483F or
CV-483G were the last versions produced, and these have LCD screens instead
of the easily scorched CRTs.

I may be able to assist further if you have any specific questions.  Worst
that could happen is that I reply with "I don't know."

73,

de AA4BR - Bernie



-----Original Message-----
From: r-1051-admin at mailman.qth.net
[mailto:r-1051-admin at mailman.qth.net]On Behalf Of jan at skirrow.org
Sent: Thursday, October 10, 2002 20:05
To: r-1051 at mailman.qth.net
Subject: [R-1051] CV-483 Mod Info


I believe the CV-483/URA-17 FSK converter was often used with the R-1051,
often in diversity setups.

I have a manual for the unit, and most of the units that I have seen have
circuitry that matches the manual. However, I have several units that have
been heavily modified - mostly the circuitry from the mark and space
amplifiers on. There are transistor changes, power supply differences and
quite a few other mods as well. Most have been very professionally done,
but I think post-production. Some are clearly field mods.

Does anyone know the purpose of these mods? I'd thought for awhile that
they got rid of the TTY high current, high voltage loop drive, and output
the actual mark and space tones, all nicely cleaned up, maybe to use with a
modem and/or computer setup. But I'm not sure.

Jan Skirrow, VE7DJX

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