Hi both look for the Radiosonde transmitters on eBay. I believe ther are two
types one with GPS and one without. They sell for about £12. The GPS module
does not supply all the nmea strings but it does have time and 1 sec ticks I
believe.
Cheers de Alan G3NYK
[email protected]
----- Original Message -----
From: "Talbot Andrew" <[email protected]>
To: <[email protected]>
Sent: 10 February 2004 15:56
Subject: RE: LF: Timing GPS
Well...
If you really want to play on the cheap and your ETrax has no PPS output, I
suppose it is remotely feasible the leading edge of the NMEA string is
probably consistent from second to second to within a few tens of
microseconds - but you'd need to measure its absolute delay somehow which
means having access to a true UTC related PPS
Perhaps we could do with a measurement session at some future LF Roundtable
There are (or at least were) some very cheap GPS modules on the surplus
market - I got an Oncore from someone who had originally paid just a few
pounds for it.
Andy G4JNT
-----Original Message-----
From: [email protected] [mailto:[email protected]]
Sent: 2004 February 10 15:36
To: [email protected]
Subject: Re: LF: Timing GPS
In a message dated 2/10/04 12:35:33 PM GMT Standard Time,
[email protected] writes:
Well, I was really thinking of GPS locked PSK rather than any incoherent
mode. WIthout the need for clock and frame timing recovery we could scrape
every possible advantage for coherent signalling. With such superb accuarcy
of timing even without carrier recovery, it seems a pity to throw all the
advantages away by using on-off keyed power detection.
I did some basic tests last year with GPS locked 1 B/s PSK and with a very
simple decoder managed to receive down to frighteningly low signal levels.
Andy G4JNT
Andy / group.
Would be happy to try this if there is a way of using the NEMA output from
my e-trex venture. No problem with a little home constructing, but would
prefer not to spend £86.
73
David
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