amateur packet radio
<communications> (PR) The use of packet radio by amateurs to communicate
between computers. PR is a complete amateur radio computer network with
"digipeaters" (relays), mailboxes (BBS) and other special nodes.
In Germany, it is on HF, say, 2m (300 and 1200 BPS), 70cm (1200 to 9600 BPS),
23cm (normally 9600 BPS and up, currently most links between digipeaters) and
higher frequencies. There is a KW (short wave) Packet Radio at 300 BPS, too.
Satellites with OSCAR (Orbiting Sattelite Carring Amateur Radio) transponders
(mostly attached to commercial satellites by the AMateur SATellite (AMSAT)
group) carry Packet Radio mailboxes or digipeaters.
There are both on-line and off-line services on the packet radio network: You
can send electronic mail, read bulletins, chat, transfer files, connect to
on-line DX-Clusters (DX=far distance) to catch notes typed in by other HAMs
about the hottest international KW connections currently coming up (so you can
pile up).
PR uses AX.25 (an X.25 derivative) as its transport layer and sometimes even
TCP/IP is transmitted over AX.25. AX.25 is like X.25 but the adressing uses HAM
"calls" like "DG8MGV".
There are special "wormholes" all over the world which "tunnel" amateur radio
traffic through the Internet to forward mail. Sometimes mails travels over
satelites. Normally amateur satellites have strange orbits, however the mail
forwarding or maibox satellites have very predictable orbits. Some wormholes
allow HAMs to bridge from Internet to AMPR-NET, e.g. db0fho.ampr.org or
db0fho.et-inf.fho-emden.de, but only if you are registered HAM.
Because amateur radio is not for profit, it must not be interconnected to the
Internet but it may be connected through the Internet. All people on the
(completely free) amateur radio net must be licensed radio amateurs and must
have a "call" which is unique all over the world.
There is a special domain AMPR.ORG (44.*.*.*) for amateur radio reserved in the
IP space. This domain is split between countries, which can further subdivide
it. For example 44.130.*.* is Germany, 44.130.58.* is Augsburg (in Bavaria), and
44.130.58.20 is dg8mgv.ampr.org (you may verify this with nslookup).
Mail transport is only one aspect of packet radio. You can talk interactively
(as in chat), read files, or play silly games built in the Packet Radio
software. Usually you can use the autorouter to let the digipeater network find
a path to the station you want. However there are many (sometimes software
incompatible) digipeaters out there, which the router cannot use. Paths over
1000 km are unlikely to be useable for real-time communication and long paths
can introduce significant delay times (answer latency).
Other uses of amateur radio for computer communication include RTTY (baudot),
AMTOR, PACTOR, and CLOVER.
A huge hamradio archive.
Usenet newsgroup: rec.radio.amateur.packet.
(2001-05-12)
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