[GreenKeys] CV-89

Wed Oct 21 13:05:16 EDT 2015

Just for the record - The only difference between the CV-89 and the
CV-89A is that the A model has the fan module on the rear. Unchanged
inside.

There is no CV-89B. But the Navy sure tried hard to make the
nomenclature confusing.

The CV-89 (officially CV-89/URA-8A) is part of the AN/URA-8A system
(two converters and a comparator) and the CV-89A (officially
CV-89A/URA-8A) is part of the AN/URA-8B system. Is that clear? How
about the fact that AN/URA-8 is completely different, incorporating
CV-60/URR converters?

Photos of these and other USN RTTY converters are at
http://www.navy-radio.com/rtty-demod.htm
and the complete URA-8B manual (including CV-89A) is at
http://www.navy-radio.com/manuals/ura8b-91490.pdf

Nick England K4NYW
www.navy-radio.com

On Wed, Oct 21, 2015 at 12:45 PM, Jim Sheldon <w0eb at cox.net> wrote:
> I too used the CV-89 in the MARS RTTY net when I was stationed in Northern
> Japan from 1963 to 1966.  The main thing I remember about it was it was
> really great on 850 Hz shift, pretty good on 425 Hz, but when the standard
> started to become 170 Hz shift, at least the A model CV-89 we had was
> somewhat temperamental in holding it's tuning.  We never saw a B model so
> I'm not sure how one of those will copy 170 shift.  It wasn't a case of the
> RX drifting as all we ever used were Collins R-390A's on the receiver side.
> We did have a couple of Hammarlund SP-600's in the rack, but they were too
> unstable for anything but listening to AM broadcast and international short
> wave audio even if you left them turned on all the time.
>
> We also had a Boehme-5C tuneable audio converter (huge boat anchor) that was
> primarily designed for 850 to 1000 Hz shift and had a BIG tunable inductor
> to set the shift.  At maximum inductance, we could copy 170 Hz shift
> reliably with it and it had a built in loop supply whereas the CV-89 did
> not.  We actually had them set up so the 5C's loop supply passed through the
> CV-89 as well and that worked OK as long as we didn't try to have both of
> them hooked to the receiver(s) at the same time - LOL!
>
> I actually wound up getting to keep the Boehme when I rotated back to the
> States in late 1966 along with a really pristine Model 19 and Model 14.
> Sure wish I had kept them, but my wife is glad I didn't, especially after I
> wound up with a huge oil streak up the shack wall when I was doing PM on the
> Model 19.  I had poured about half a can of 30 weight Pennzoil on the felt
> clutches and started it up - forgot to set the loop supply on and it ran
> open with the cover off long enough to sling most of that 30 weight right up
> the wall behind the machine.  Good thing we had good paint as it did clean
> up okay.  Learned my lesson after that and did all the PM outside or in the
> garage.  Once personal computers arrived and RTTY to ASCII conversion
> programs became available, I gave the machines back to the MARS program.
>
> I did pick up an absolutely brand new HAL ST-8000A that was still in an
> unopened HAL shipping container and currently use it as my primary T/U with
> MMTTY as secondary.  We were just getting the ST-8000's in the intelligence
> monitoring community when I retired from the Army Security Agency in 1981 so
> I was familiar with it and even though I paid too much for it, HAL was very
> helpful in getting me the info and parts I needed to change the MIL plugs on
> it to DE9's.  Their DSRTTY-WIN program is still available and I use that
> with the 8000A to run RTTY and ASCII with it.
>
> Jim Sheldon - W0EB
> Park City, KS
> ------ Original Message ------
> From: "Linger, Michael I" <mlinger at civil.tamu.edu>
> To: "'GreenKeys at mailman.qth.net'" <GreenKeys at mailman.qth.net>
> Sent: 10/21/2015 11:14:49 AM
> Subject: [GreenKeys] CV-89
>
>
> I used the CV-89 converters for several years in the military as well as it
> was my only converter in ham use in the ‘70’s while in Navy MARS.  I had no
> troubles at all in the military with them and rarely any trouble with my own
> units while in MARS, which I used several times a week for RTTY net
> operations.  I still have several of them and really like them.  These units
> were designed to operate with a rather large fan unit on the back of them,
> mainly because they were to be used with their brothers (another CV-89 and a
> CM-22 comparator unit), all stacked in a rack that runs pretty hot when all
> turned on.  However, I used my CV-89 units without the fan and by themselves
> and found they ran with no issues.  I also ran my CV-89(B version) with an
> outboard simple 3 stage op-amp 741 input limiter at the audio input which
> enhanced the performance significantly.   The only tubes I ever replaced
> were the 6x4 rectifier tube, which runs hot regardless of where it is, and
> occasionally I replaced the 6AQ5 tubes in the keyer circuit.  All the tubes
> in this unit are available on ebay for cheap, as well as all over the
> internet at various sites.   Over my 52 years in amateur radio I think I’ve
> had nearly every kind of TU they’ve made in the past, including the ST-8000,
> ST-8000A, Flesher, DT-600, Heathk 3030, URA-17, CV-116, etc., and all the ST
> Hal units and all I’ve kept is my trusty CV-89B’s, the ST-6, and my Dovetron
> MPC-1000CR.  That said, I have to say it’s pretty hard to argue with the
> High-Tech equipment we have today for data communications.  So ask yourself
> what you want to have fun with and go from there.  If it’s the old vintage
> stuff, don’t be afraid to acquire and play with it to make it work for you
> because you’ll learn allot and move on.  If the old stuff is what you like
> you wouldn’t be on this forum asking about archaic things like Teletype!
>
>
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