[TenTec] Some Observations on Orion Stability/Calibration

[Carl Moreschi]

I am having a hard time understanding where this propagation frequency error
could come from.  It seems to me that if WWV was at 15 mhz and I was
receiving a 14.999990 frequency, this 10 hertz frequency error would be
building up some place in a time warp!  I could understand an instantaneous
error over a few milliseconds but it should average out to be right on the
mark in a few seconds.  If it doesn't, then either WWV or my station are
moving relative to one another and there is a doppler shift going on!

Carl Moreschi N4PY
Franklinton, NC
----- Original Message -----
From: "Gary Hoffman" <ghoffman at spacetech.com>
To: <geraldj at isunet.net>; <tentec at contesting.com>
Sent: Monday, June 02, 2003 10:39 PM
Subject: Re: [TenTec] Some Observations on Orion Stability/Calibration


> 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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>
>
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