[TenTec] Some Observations on Orion Stability/Calibration

[Gary Hoffman]

Jerry...

How do you know that propagation delays cause about a 1 ppm error ?  I have
not found that figure referenced elsewhere, and would like to know how to
measure or estimate it.  Thanks !

Gary

----- Original Message ----- 
From: "Dr. Gerald N. Johnson, electrical engineer" <geraldj at isunet.net>
To: <tentec at contesting.com>
Sent: Monday, June 02, 2003 3:05 PM
Subject: Re: [TenTec] Some Observations on Orion Stability/Calibration


> TC stands for Temperature Compensated, NOT Temperature Controlled. So
> the oscillator controls should be responding to its environment.
>
> But HF propagation causes short term variations in frequency of about 1
> part per million, 20 HZ at 20 MHz WWV so the measurements may not be of
> the TCXO but likely are of propagation changes. Frequency measurement
> specialists expect it to take a month of averaging HF WWV signals to get
> to within that 1 PPM. Hoping to do it in hours just isn't going to
> happen.
>
> Only propagation at VLF, like 20 and 60 KHz can allow better frequency
> distribution than a PPM, and then its not right if there's an aurora
> about like there has been last week.
>
> 73, Jerry, K0CQ
>
> -- 
> Entire content copyright Dr. Gerald N. Johnson, electrical engineer.
> Reproduction by permission only.
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