[time-nuts] Re: WWVB Antenna
bill at iaxs.net
Tue Mar 8 14:09:13 EST 2005
Interesting that they went from mechanical filter to crystal
to LC with commercial inductors. Apparently tight filtering
did bad things to the phase performance. That would not be
noticed until oscillators stability improved.
The loop resonating capacitor is in the neighborhood of 1900 pF
until the last one, when it drops to around 1500. So your turns
count could vary by serial number.
Those antennas were all built before the WWVB power upgrade in
December 1977. Perhaps that design is overkill now. I'm doing
fine with a 100 turn, 3' square non-resonant loop in MN.
From: Tom Van Baak
Sent: Tuesday, March 08, 2005 12:30 PM
Also see the design of the HP 10509A; the HP 117A antenna:
I was asked recently how many turns of wire are inside the HP
loop antenna. Does anyone know (to spare me from opening one
of mine up)?
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