Eddy,
Well, "it depends". One thing that will add to the drift rate is how often and to what degree the final amplifier is exercised. A fan pulling the hot air out helps if it is located above or behind the final amplifier cage. Because of this, the R4C is often used for primary frequency control with a C line. My experience with the B line, C line, and 7 line, is that there are "classes" of drift due to either production line variations, component lots, or luck of the draw. For example, I've had TR-7s that drift well under 50 hz per hour while others have drifted over 200 hz per hour and needed 18-24 hours to stabilize; too, some never stabilized. Enjoy those Drakes. And don't forget the Drake nets... 73, Evan, K9SQG -----Original Message----- From: Eddy Swynar <deswy...@xplornet.ca> To: drakelist <drakelist@zerobeat.net> Sent: Fri, Nov 25, 2011 9:33 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 _______________________________________________ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
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