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
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
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
e
-Original Message-
From: time-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
>>> So your frequency drift in this example is 1.7e-11 / month.
>> Not quite, you need to take the sign of the frequency
>> difference into account.
> But the sign of the difference would be obvious from the rotation
> direction of the Lissajous.
Only if you remembered to include the directio
On 11/7/09 12:29 PM, "Bruce Griffiths" 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 difference i
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" wrote:
> Time-Nuts,
>
> I recently fired up an Efratum LPRO and have been watching the slowly rotating
>
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 Lis
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 see
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
_
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 Liss
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