At the time, the year would have been written as MCXI, so no palindrome
would have been possible!
Bill
From: time-nuts on behalf of Bill Metzenthen
Sent: Wednesday, February 5, 2020 1:17 AM
To: time-nuts@lists.febo.com
Subject: Re: [time-nuts]
Just a thought, as I have no experience with mechanical clocks. Couple your
atomic clock 1pps signal to a mechanism that weakly mechanically couples to
your chronometer spring-mass-escapement system in some way (assuming 1 tick per
second natural frequency for your chronometer). Rely on the
The "N" indeed points north. This is because these large
reference-station choke-ring antennas are often calibrated for phase
center with respect to north. Did you get the phase center calibration
data with your antenna?
Pointing the "N" towards north will not have much effect on timing
Hello,
This is a topic that interest me greatly as well. Some of the work we have
done uses a digital frequency tracking loop to generate frequency errors
directly from sampled data using a sampling system and ethernet system of our
own design. We opted for using a look-up table-based DDS in
Hello!
I have done this and can attest that it works well. I did not use a TCXO,
though. I used a 48 MHz, third-overtone AT-cut crystal in a Colpitts
oscillator configuration. The vacuum flask was ovenized to maintain
temperature near the stationary point of the temp characteristic (near 50
My calculation was a bit hasty. Q_rad is around 123, not 7e6 (misplaced factor
of 2pi). Still pretty bad, tho'. So, we have 1/24 -1/123=1/Qloss or Qloss =
25; typical of what you'd find in a lumped LC circuit.
Cheers
From: time-nuts on behalf of Bill Slade
Hi,
Are you losing the least significant digit in your frequency measurement? A
double precision word has 52 bits of significance+sign, roughly corresponding
to 15 decimal places. Adding 3uHz to 1Ghz (or hundreds of MHz) is just about
on the limit of generating significance errors due to
Hi again,
The very best GNSS antennas tend to be based on suspended patch antenna
(air-dielectric) structures because they give the best
bandwidth/radiation efficiency (and hence, noise temperature)
performance. The very best include choke-rings for multipath
suppression (Dorne-Margolin &
Hello Denny,
Things to keep in mind:
1. To keep noise performance, LNA gain at the antenna should be at least 10
dB above total losses in antenna cable & distribution network. 13-16 dB above
is better. Something like this would be more than suitable for a 30 ft run:
