Heat Related Frequency Drift 6300

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Having searched this site and the Internet for clues that others are experiencing my specific problem and finding nothing, I'll take the liberty of raising the subject. My 6300 (running SSDR 1.8.3) exhibits heat related frequency drift. As one would expect, it is most pronounced on six meters.

Those of you who are familiar with JT-65 signals displayed on the waterfall will know that the "sync pulses" represented along the left side of the JT-65 signal should be displayed as a vertical line, exactly perpendicular to the frequency axis like this: | . Initially, during a JT-65 session, that is how it is; however, as heat increases (as reported by SDR Monitor 2.0.3), these lines begin to lean, indicating frequency drift. The phenomenon grows more dramatic as temps increase. When the 6300's fan kicks in during a transmission, meaning that the temp has reached 70C, in the next receive sequence those lines lean like this: / , signifying a frequency that is drifting. as the internal temperature of the 6300 decreases. Over the course of the 47 second receive cycle, the drift can be 3-4 Hz. 

Is this inherent in the 6300 XO design? If I could afford it, I know I could buy a 6700 with the GPS disciplined oscillator, but what other possibilities are there that wouldn't break the budget? I never experienced this problem with my FTDX-3000, but I'm a Flex guy now and I ain't going back to knobs and dials. 
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Ben - AE4NT

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  • sanguine

Posted 3 years ago

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Photo of Ben - AE4NT

Ben - AE4NT

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Official Response
Well, after opening a support ticket, Tim did some tests with a baseline 6300, and compared his readings with mine when I duplicated the tests here. Conclusions:

1) My 6300 performance was nominal, both case temp and frequency drift.
2) The laptop cooler recommended by Steve G1XOW didn't have a material effect on the case temp while transmitting, but it cut the recovery time to original ambient temperature during subsequent receive cycle by 50%. So, overall, operation will be cooler with the increased air flow.
3) You all talked me into doing the Trade-Up deal for the 6500, so I ordered one. Thanks for making me spend the money. I hope you're satisfied now. :)

Tim, as usual hopped right on this and did what he needed to do to make things right. And he didn't try to talk me out of the upgrade.

73 de AE4NT