With Loran C shutting down in Jan, curious if anyone still uses it.
I have a z3801 but always liked the Austrons 2100s as another way to check
everything.
I pulled the old Gertch RLF-1 out of the basement and it still works.
(retired it 9 years ago)
But a far cry from the Loran chains accuracy and
Time-Nuts,
I recently fired up an Efratum LPRO and have been watching the slowly rotating
Lissajou figure produced when comparing it's output with that of a GPSDO on a
scope. It's a
beautiful thing (the weather is too cool to watch paint dry...)
I thought the period of rotation of the
or stated in another way: your two sources differ by 5.5 parts in
10^-10
Well within the specification for the Rb. But to be precise, but if
you wanted to know the absolute accuracy of the Rb then you would
need to know the accuracy of the GPSDO at that moment in time.
Jeffrey Pawlan
Mark,
Your 5.5 mHz is correct for the frequency difference But
note that's out of 10 MHz so the *relative* frequency error
is 5.5e-3 Hz / 1e7 Hz, or 5.5e-10 (unit-less).
The other way to look at it is this:
The nominal frequency is 10 MHz, so one period is 100 ns.
Your Lissajous pattern is
Tom Van Baak wrote:
Mark,
Your 5.5 mHz is correct for the frequency difference But
note that's out of 10 MHz so the *relative* frequency error
is 5.5e-3 Hz / 1e7 Hz, or 5.5e-10 (unit-less).
The other way to look at it is this:
The nominal frequency is 10 MHz, so one period is 100 ns.
Your
You got it exactly. The relative phase between the two signals (as
displayed by the Lissajous) rotates one cycle in 182 seconds.. E.g. 1/182 Hz
difference.
On 11/7/09 11:34 AM, Mark Amos mark.a...@toast.net wrote:
Time-Nuts,
I recently fired up an Efratum LPRO and have been watching the
On 11/7/09 12:29 PM, Bruce Griffiths bruce.griffi...@xtra.co.nz wrote:
Tom Va
100 ns / 182 s = 5.495e-10 on November 7
100 ns / 188 s = 5.319e-10 on December 7
So your frequency drift in this example is 1.7e-11 / month.
/tvb
Not quite, you need to take the sign of the frequency
-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Hal Murray
Sent: Saturday, November 07, 2009 3:50 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Calculating frequency differences using Lissajou
figures
So your frequency drift
Mark Amos wrote:
Time-Nuts,
snip
In this case the period between in-phase and in-phase is 182 seconds yielding
a rotation frequency of 5.5 mHz. So, is 5.5 mHz the frequency difference
between the two 10 MHz
oscillators? Or am I missing something obvious?
Thanks, in advance,
Mark
Bill,
I did a two sets of measurements using different methods. In the first, I
watched the two waveforms in dual trace mode. The Trimble was on channel 1
(stationary) and the LPRO
was on channel 2 (slowly drifting to the left). I started timing when they
were phase (Channel 1 and Channel 2
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