karn (11/11/82)
QST DE W3IWI
News Release on Packet Radio Activities
de AMSAT 16 October 82
-------------------------------------
*** Long-haul Packet Test Successful ***
. . . . . .
On 16 October 1982, from 16:45 UT until 17:00 UT, a success-
ful long-haul Packet Radio demonstration QSO took place between
Maryland and Texas; the stations involved were Bob Diersing,
N5AHD in Corpus Christi and Tom Clark, W3IWI near Washington.
The QSO took place on the 10 meter band at 28.300 kHz with both
stations running FSK at a 1200 baud rate using HDLC protocol
currently accepted as amateur radio standards.
. . . . . .
This demonstration represents another phase of the AMSAT
activities to advance the state-of-the-art in amateur radio
communications technology development and the tests were con-
ducted to test the suitability of various existing hardware and
protocols under weak-signal and QRM conditions in anticipation
of the AMSAT Phase-3B satellite launch in February, 1983, and
to help in the planning of future satellite missions including
a possible dedicated packet radio mission a few years from now.
. . . . . .
The demonstration QSO took place just one week after a land-
mark meeting held under AMSAT's auspices to establish and co-
ordinate common packet radio protocols. This meeting in the
Washington,DC area was attended by representatives of packet
radio groups from San Francisco, Tucson, St. Louis, Washington
and New Jersey. The meeting succeeded in reconciling minor
differences that had evolved between the various groups during
their R&D activities. The goal of establishing common protocols
was focused on the upcoming satellite launches when it will be
possible, for the first time, for the different packet radio
groups to reliably inter-connect local networks on a global
basis.
. . . . . .
During the long-haul test, both N5AHD and W3IWI were using
special 8085 microprocessor based Terminal Node Controller
(TNC) hardware developed in Canada by the Vancouver Area
Digital Group (VADG), with software developed in Vancouver, San
Francisco and Washington. They both used conventional "202A"
FSK modems operating thru 100 watt SSB transceivers. A number
of packets were successfully exchanged in both directions and
the TNC board's software automatically verified the accuracy of
each transmission. The HDLC protocol dictates that if any error
is detected, the transmitting station re-tries until an error-
free copy is received. In the test QSO, the number of re-tries
required never exceeded three. The stations had conducted
previous long-haul test experiments through the AMSAT-OSCAR-8
satellite.
. . . . . .
W3IWI has been involved in a number of previous AMSAT demon-
stration tests including initial feasibility demonstrations
using satellites to locate downed aircraft which led to the
international Search-and-Rescue Satellite (SARSAT) program and
tests of digital phase-shift keying (PSK) techniques to be
employed on the Phase 3 satellite series. N5AHD has developed
automated, real time telemetry acquisition techniques for the
UoSAT-OSCAR 9 satellite and operates AMSAT's Computer Bulletin
Board System (CBBS) which can be accessed at (512)852-8194.
Both N5AHD and W3IWI have been frequent contributors of amateur
radio software which is available through the AMSAT Software
Exchange (ASE). Further information about AMSAT, ASE or AMSAT's
CBBS can be obtained by calling the CBBS or by writing:
AMSAT
Box 27
Washington, DC 20044
. . . - . -