[time-nuts] Old Loran

Max Robinson max at maxsmusicplace.com
Sun Jul 13 13:22:33 EDT 2008


Hal Murray wrote.

>How good were crystals back in WW II time frame?

>Does anybody know anything about early Loran?  I'm guessing that the
>secondary stations listened to the primary and sent their pulse X
>microseconds after they heard a pulse.  How did they implement that delay?
>What sort of filter/PLL did they have on receiving the primary station?

>What is current Loran navigation accuracy?  What was it like in the old 
>days?


Each station in the old loran system used a different pulse rate.  You could 
hear the pulses walking across one another giving a rising and falling sense 
of rate.  There was some frequency diversity as well.  I never really 
understood how the old system worked.

In the 60s a carefully designed ovened crystal oscillator could do about 1 
part in ten to the ninth.  In WWII I suspect it was an order of magnitude 
worse.

Regards.

Max.  K 4 O D S.

Email: max at maxsmusicplace.com

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----- Original Message ----- 
From: "Hal Murray" <hmurray at megapathdsl.net>
To: <time-nuts at febo.com>
Sent: Sunday, July 13, 2008 3:43 AM
Subject: [time-nuts] Old Loran


>
> I found this interesting.  It's a chunk of the memoirs of a Coast Guard
> Captain who was in charge of Loran in Japan from 1961-1964.
>
> http://www.uscg.mil/history/WEBORALHISTORY/CAPT_David_Sinclair_29.html
>
> It's half Coast Guard history/nostalgia, half his memories of Japan, and a
> little bit of Loran.  But I thought that little bit was neat.
>
> How good were crystals back in WW II time frame?
>
> Does anybody know anything about early Loran?  I'm guessing that the
> secondary stations listened to the primary and sent their pulse X
> microseconds after they heard a pulse.  How did they implement that delay?
> What sort of filter/PLL did they have on receiving the primary station?
>
> What is current Loran navigation accuracy?  What was it like in the old 
> days?
>
>
> -- 
> These are my opinions, not necessarily my employer's.  I hate spam.
>
>
>
>
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