[time-nuts] Simulating LORAN-A GRI Timing Generator

Magnus Danielson magnus at rubidium.dyndns.org
Sat Jan 8 05:54:25 UTC 2011


On 08/01/11 05:04, J. Forster wrote:
> Magnus,
> See my post of a few minutes ago.
> The GRI and Delay counters need to be 5 decimal digits. My current
> thinking is manual entry of the numbers via BCD coded thumbwheel switches.

If you only need a static location that will be fine. Naturally you tune 
it up to the ships current (final?) position. Good exercise for the 
visitors. :)

> LORAN-A has 24 possible GRIs; in three blocks of 33 PPS; 25 PPS; and 20
> PPS. It also has 4 RF frequencies.

I did a fashinating read-up here:

GRI is a LORAN-C term if I get it correctly, where as PRR is used 
together with frequency indication in LORAN-A.

> Currently I plan only one Slave, but a second would be an easy addition.

Indeed. Considering the chain that used to be there, you could allow for 
two chains to be setup on the same frequency (1H chains).


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