[OZAPRS] What's Happened to HF APRS in VK?

[vk6ad]

Greetings

My name is Phil Maley, vk6ad. I helped build and have operated VK6BBS at
Wireless Hill for the last 10 years and before that I helped manage the
current VK6BBR packet station at Roleystone and operated a RTTY/Packet
gateway using the RTTYGATE software. VK6BBS has a 300baud HF port on
14.109MHz using a commercial Rockwell-Collins transceiver and a PK232. I
also operate VK6DLX, a linux based internet wormhole station that
primarily feeds traffic to vk6bbs. VK6DLX also runs the WA4DSY APRS
server software.

The biggest problem I have had operating the HF port on vk6bbs over the
years is netting the tx and rx. As Chris mentioned, the station needs to
stay within a very narrow tolerance of the nominal mark and space
frequencies over long periods of time. It's not impossible for a home
station but a remote hf station becomes a real chore. We used to forward
packet data to Adelaide and Karratha on 14.109 but it became impossible
to keep everyone netted and in the end everyone gave up. The VK6BBS
system is still open but gets almost no traffic.

Another thing to think about is that 300 baud HF packet is very wasteful
of bandwidth. Is it too late to consider a national/international PSK31
aprs network?  For frequency control we could nominate one station as
the "master" station and others could cascade out from that in a
hierarchical frequency netting system similar to the internet time
system. I'm letting my imagination run away a little here, but could we
adapt some of the great software that's around to automatically fine
tune the computer audio tx and rx without touching the radio tuning?
Each station could send an automatic netting message to its
lesser-ranked neigbours telling them to adjust their TX frequency and
the lower-ranked stations could automatically keep their receiver netted
to their higher-ranked neigbour.

Of course the mobile station operators will be screaming by now that
they are stuck with 300 baud packet because that's the only practical
equipment that's available. Has anyone played with a PIC based PSK
modem? I did a quick search on google and found over 140 references to
PSK31 using PIC modems, so it might be quite practical.

Food for thought.

73 to all
Phil Maley VK6AD

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