Date: Tue, 21 Aug 2018 22:49:49 -0400
From: "Paul Christensen" <w9ac@arrl.net>
To: <topband@contesting.com>
Subject: Re: Topband: OT - US Hams, WWV closure
<Several options: (1) CHU is still operating on several HF frequencies that
reasonably cover North America; (2) In the U.S., AM broadcast stations are
required to maintain +/- 20 Hz carrier stability (73.1545). However, nearly
all modern BC transmitters can easily meet 2 Hz, and some are now
phase-locked to a precision standard.
Most modern amateur gear covers the MW band. One could sample several AMBC
stations, throw out the outliers, then calculate a geometric mean and attain
a very accurate reference. Incidentally, some legacy ham-band-only gear
never did cover WWV -- or if it did, it was received by a different band
mixing scheme, then a pre-selector is peaked for resonance.
In the shack, I use a GPSDO with a distribution amp that locks several
transceivers and some test equipment. A surplus $100 USD rubidium standard
is Velcro-strapped to my HP frequency counter. It comes up to temperature
and locks within 5 minutes of powering. The accuracy of both devices far
exceeds my needs.
Paul, W9AC
## After very carefully aligning the .25 ppm TCXO in both my yaesu MK-Vs...
using the 20 mhz wwv, I tuned across the entire AM 540-1710 khz band, and
only found
ONE station that was dead on freq, and that was CBC on 690 khz, in
Vancouver BC.
The rest were several hz too high..or several hz too low. Some were as
much as 20 hz off freq.
## Even if you could find just one AM broadcaster that was dead on freq,
the 540-1710 band is
much too low to align a TCXO. If say you were off by 1 hz at 1000 khz,
you would be off 10 hz
at 10 mhz..and 30 hz at 30 mhz, etc. And with no high freq WWV to
compare to, you would have no
clue as to which of the myriad of 540-1710 AM broadcast stations is actually
anywhere close to being on freq.
## CHU broadcasts on just 3.33 mhz, 7.85 mhz..and 14.67 mhz. All 3 are
pretty weak here on the west coast.
WWV is instead used here on the west coast, as CHU is typ too unreliable.
The price tag on all this surplus GPSDO / rubidium gear will skyrocket if
and when WWV is shut down.
I can not see WWVB being shut down at all, too many consumer devices rely on
it.
Jim VE7RF
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