----- Original Message -----
From: "Eddy Swynar" <[email protected]>
To: <[email protected]>
Sent: Friday, November 25, 2011 11:32 AM
Subject: [Drakelist] T-4X Stability
Hi All,
The manual for my T-4X states that stability is "LESS THAN
100 CYCLES AFTER WARM-UP". My question is simply this: how
long, exactly, is an accepted period of "....warm-up"...?
After all of the hoops that I've jumped through in
stabilizing the PTO in my rig (re-buiding it almost,
actually!), I decided this morning to actually measure its
drift. I used my ICOM 751A transceiver (in general
coverage mode) as the frequency "umpire", and tuned it
directly to the Drake PTO's output frequency of
5454.0-KHz. Both rigs were in the basement overnight,
where the ambient room temperature was 59F. I measured the
frequency a total of SIX times, i.e. (1) immediately at
the start of the test, (2) 3 minutes into the test, (3) 15
minutes into the test, (4) 30 minutes into the test, (5) 1
hour into the test, and finally (6) two hours into the
test...
Here are my results:
(1) 5454.0-KHz (cold start);
(2) 5454.0-KHz (unchanged from cold start);
(3) 5453.5-KHz (downward drift of 500-Hz from cold start);
(4) 5453.0 KHz (downward drift of 1-KHz from cold start);
(5) 5452.8-KHz (downward drift of 1.2-KHz from cold
start), and,
(6) 5452.8-KHz (unchanged).
So---it looks like the rascal that I have here stabilizes
after a good hour of steady warm-up, which leads me to
suspect that maybe "warm-up" to the writer of the manual
was, in fact, just that, i.e. one hour...?
No matter, it was a most interesting exercise---and I sure
would be curious if my rig's performance might match that
of some of the other T-4Xs that are out there...although I
dare say, probably not everyone has as thick a hide as I
do in being able to withstand a 59F ambient room
temperature...! Hi Hi.
~73~ de Eddy VE3CUI - VE3XZ
I suspect this is normal. An hour for all parts to
reach some sort of thermal equilibrium is not very long.
Some equipment takes a lot longer, for instance, somewhere
in the TMC literature its stated that the stabilization time
for the GPR-90 receiver is 48 hours! I think this is
probably typical for a lot of equipment. OTOH perhaps the
temperature compensation in your TX is not quite on. The
fact that it drifts in the same direction is IMO a good
sign. Some compensation results in drift that varies in
direction as the temp changes.
--
Richard Knoppow
Los Angeles
WB6KBL
[email protected]
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