[aprssig] APRS on HF

[Julian, G4ILO]

What is the purpose of APRS on HF? Most of what I have read about APRS
has said that the purpose of APRS is to provide *local* information.
In another thread someone has said that if you can't reliably reach
someone more than two hops away use packet, which implies that APRS
isn't meant for long distance messaging either.

Due to the propagation characteristics of HF, what you receive on HF
is anything but local. Here in Europe we have stations in the south of
France gating from VHF to HF. From them I receive information about
French VHF/UHF repeaters or French ham radio club meetings which is of
no use to me.

Having run a 30m IGate (G4ILO-1) for several months now I have often
been the station that gates European HF mobiles to APRS-IS. I
understand that in areas where there is little VHF coverage (which
includes much of the UK) a mobile has a better chance of being gated
if they use HF, even though they will be gated by someone 1,000 miles
away. So is that the only real purpose of APRS on HF, to gate HF
mobiles? And if so, why do HF IGates need to transmit?

Julian, G4ILO
G4ILO's Shack: www.g4ilo.com