[time-nuts] [Fwd: Re: Simulating LORAN-A GRI Timing Generator]

paul swed paulswedb at gmail.com
Sat Jan 8 15:32:03 UTC 2011

Well I might be crazy but this seems perhaps easy since reading the link
The slaves listened to the master and provided a pulse.
So for at least a rate 1 chip could do the job. Essentially the master pulse
and then a delay to the slave position.
If I am interpreting the info correct the pulse were 40 us wide and made of
the carrier frequency like 1.95 MC.
A solution would need 2 or 3 of these widgets to give the 3 lines. But do
not need to be synchronized because the value of the informations contained
within the delay relationship between the master and slave.

On Sat, Jan 8, 2011 at 10:08 AM, J. Forster <jfor at quik.com> wrote:

> Pondering some more on this, doing some calculations (spread-sheets) the
> actual scheme emerge... the range of 0 to 7 is not selected by accident.
> The base pulse repetition rate is 30 ms, 40 ms and 50 ms. The pulse
> repetition rate modifiers modifies the repetition rate by -100 us per
> step. It would only take two (or possibly three) wheels to select PRR.
> This explains the high rate starts with 33 3/9... it also makes the
> receiver design easier to understand.
> Very interesting observation! I did the calculation using Excel (attached)
> but missed the 100 uS increments., I was blinded by modern precision.
> Since the LORAN Indicator has sync circuits, your observation is a nice
> simplification. Thank you.
> So a 10 kHz source would suffice for PRR settings. A phantastron divider
> from a 100 kHz standard should do it in those days technology, if not a
> 10 kHz standard was used directly.
> Only the delayed pulse would need the full set of thumb-wheels.
> Cheers,
> Magnus
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