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amateur packet radio
(foldoc) | amateur packet radio
(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 mailbox 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 (ftp://ftp.ucsd.edu/hamradio/).
Usenet newsgroup: news:rec.radio.amateur.packet.
(2001-05-12)
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general packet radio service
(foldoc) | General Packet Radio Service
GPRS
(GPRS) A GSM data transmission technique
that transmits and receives data in packets. This contrasts
with systems that set up a persistent channel. GPRS makes
very efficient use of available radio spectrum, and users pay
only for the volume of data sent and received.
See also: packet radio.
(1999-09-12)
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