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APRS RF DX? (Was RE: [aprssig] APRS in Atlanta - flooding the network)

Dave Baxter dave at emv.co.uk
Wed Oct 12 09:19:55 UTC 2005


Morning....

> The thing that bothers me about the long distance packet issue is
this,
> I doubt anyone has the need to go long distance in all directions at
once.

AFIK with a little fiddling of SSID's etc, you can "steer" your APRS RF
packet in the 4 general directions. NSE&W if you need...  Comments Bob?

As for inserting the native call's of digi's to build a route yourself.
One fatal flaw in that argument.  It assumes you know the call's in the
first place, or they can even be identified.  Many digi's don't beacon,
& many don't substitute call's (not sure if Widen-N even allows it?) so
you don't know they are even there, except that "something" passed the
packet on.

In the UK (and maybe other places) we have to have our main station call
sign sent at least every 15 mins in CW on the data channel.  (That
doesn't help congestion, but we have no choice in the matter!)  It's
also done by AFSK'ing between the two tones the TNC uses.  (I don't know
of any that just send as true monotone CW, and I was playing around with
the SOTT code trying to do that, with less than a modicum of success,
sadly.)  As a result, it's not easy to read, even for experienced CW
op's, especially when mobile plus they often get sent at 20WPM or more,
trying to cut down the congestion caused I guess...

In any case, that is only of use if you know both where it is, and can
hear it to read the ID, and it doesnt get stomped on by a more local
packet/APRS station, as most TNC's don't regard someone sending the CWID
as a "Busy" channel.  The Kenwood TH-D7 and 'D700 are I think exceptions
to that rule.

Going to go hide in an APRS hole now, rather a lot of those about in
these parts...  73

Dave G0WBX




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