[aprssig] DigiTraveller questions
aprs at kd4rdb.com
Mon Oct 11 13:20:59 CDT 2004
I think the almanac messages are repeated very regularly (like a few times a
minute)... Each satellite also transmits all of the other satellite's data at
a much lower rate... in 24 minutes. So if you can only see one bird, it will
take 24 minutes to get the data for all of them. If you could see 12 of the
satellites, you could get the data from all 12 of them at a time in probably
less than one minute.
Now I'll just sit back and wait for Gerry to correct me!
Quoting "Curt, WE7U" <archer at eskimo.com>:
> On Mon, 11 Oct 2004, Earl Needham wrote:
> > I am thinking of an active antenna because of the LOOOOOONG time
> > it takes to acquire a fix. Might help, might not, but I'm considering it.
> Consider instead rigging it up to be powered externally and wiring
> it permanently to your car battery (through a regulator). Then your
> times will be much shorter 'cuz you won't have to download the
> satellite almanac each time you want to use it. The almanac takes
> 15 minutes minimum to snag from the satellites (I think that's
> Curt, WE7U http://www.eskimo.com/~archer
> "Lotto: A tax on people who are bad at math." -- unknown
> "Windows: Microsoft's tax on computer illiterates." -- WE7U
> "The world DOES revolve around me: I picked the coordinate system!"
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