karn@mouton.UUCP (11/02/84)
Gateway, The ARRL Packet-Radio Newsletter
October 23, 1984
Volume 1, Number 6
Electronic edition.
TELEPORT STA GRANTED
The FCC has granted the joint AMSAT/ARRL request for a special
temporary authorization (STA) permitting operation of automatic
digital teleport stations. (For complete discussion of this
request, and a list of stations involved, see Gateway issues 1
and 5.) The FCC "concluded that the automatic relaying of
digital messages between amateur stations on earth and amateur
satellites via intermediary stations (stations in teleport
operation) may contribute to the advancement of the technical and
communication aspects of the art of radio."
The following sections of the Amateur Radio Service rules have
been waived for authorized stations:
"97.126 (a) is waived to permit an amateur station engaged in
teleport operations to retransmit automatically the radio
signals of other amateur radio stations.
"97.126 (b) is waived to permit a remotely-controlled amateur
station engaged in teleport operations to communicate with
stations which are not shown on such a station's network
diagram.
"97.79 (b) is waived to permit an amateur station engaged in
teleport operations to be operated under automatic control
without the presence of a control operator at a control point
of the station; provided that devices are installed and
procedures implemented to ensure compliance with the the
Commission's rules at all times; and, provided further that
upon notification by the Commission of improper operation of
a teleport station under automatic control, such automatic
control shall be discontinued immediately until all
deficiencies have been corrected."
Authorized stations may operate satellite uplinks and downlinks
on 144-146 MHz and 435-438 MHz. Terrestrial inputs and outputs
may be on any amateur frequency at or above 50 MHz where digital
communications is permitted.
This STA expires 180 days from October 18, 1984. Good luck to
all stations involved.
PACKET RADIO TELECONFERENCE RADIO NET
"Packet Radio Overview and Prospective" will be the subject of
the December 2nd North American Teleconference Radio New (TRN).
This net, heard on over 150 gateway stations (mostly VHF
repeaters) across the U.S. and Canada and on the OSCAR 10
satellite, will explain what packet radio is, describe how to get
started in it, point out the benefits to you, and outline the
pitfalls to be avoided by the beginner and expert alike. The
speakers on this TRN will be none other than Lyle Johnson,
WA7GXD, and Harold Price, NK6K.
Lyle is President of the Tucson Amateur Packet Radio Corporation
(TAPR) and was one of the primary developers of the TAPR terminal
node controller (TNC) hardware. For his work in developing the
TAPR TNC, Lyle was awarded the 1984 Technical Excellence Award at
Dayton. Looking to the future, Lyle is responsible for the
processor design for the upcoming amateur packet satellite
(PACSAT). He became active in packet radio in 1981, the pioneer
days for this new technology.
Harold is a Director of TAPR and was on the team that designed
the software for the TAPR TNC. He is also the AMSAT Project
Manager for PACSAT. Harold is another packet-radio pioneer,
having first become active in that technology in 1982.
Packet radio offers opportunities for both the traditional
communicator and for the experimenter. Learn about packet radio
from two of its leading developers by tuning into TRN, Sunday,
December 2, 1984, at 6:00 PM CST (0000Z). For a complete list of
gateway station locations and frequencies, write the TRN Manager,
c/o Midway Amateur Radio Club, P.O. Box 1231, Kearney, NE 68847-
1231 (S.A.S.E. please, Canada excepted). Those of you on
Compuserve HAMNET can find this list in the XA4 data base.
From Midway Amateur Radio Club
GATEWAYS "DOWN UNDER."
On September 1, from 2000Z to 0000Z, VK2BVD and ZL1AOX maintained
a fully "connected" 1200-bit/s data link between Sydney,
Australia, and Auckland, New Zealand, on the 20-meter band.
Propagation conditions were excellent, and there was little
multi-path over the 2650-km, one-hop path. Substantial files
were transferred in each direction.
The following day, at the same time, an HF/VHF packet gateway was
established using store-and-forward techniques with link-level
acknowledgments. A total of 5 terminal node controllers (TNCs)
and two computers were linked via 2-meter and 20-meter packet
radio. Both ZL1AOX, in Auckland, and ZL3QL, in Cristchurch, were
able to access the 2-meter local-area network (LAN) in Sydney.
The gateway was in operation again on September 3, with a VHF
beam orientation problem solved. ZL1AOX was able to connect to a
host computer at VK2ZRQ and interactively operate the machine for
over an hour. Both the HF and the VHF ports of the VK2BVD
gateway functioned as expected.
Other stations monitoring these activities included ZL3THJ,
VK2AQG, VK2AYD, VK2XY, VK2ZXQ, and VK2KFJ. Via VK2BVD
TRANSLATION OF GATEWAY
As part of its continuing effort to promote digital communication
modes, the Radio Club of Chile has been translating Gateway into
Spanish. We received a photocopy of the Spanish edition of the
premier issue of Gateway, including an excellent translation of
Jon Bloom's "Introduction to Packet Radio." If you need the
Spanish edition of Gateway, contact
Radio Club De Chile
Departamento De Comunicaciones
Centro De Documentacion
Nataniel Cox 1054 - Santiago De Chile
CHILE
RF DESIGN TEAM
A few Motorola engineers, members of the Florida Amateur Digital
Communications Association (FADCA), want to design radios for
amateur digital operation around 900 MHz (there will soon be an
amateur assignment in this band). This group, chaired by Tom
Kneisel, K4GFG, is looking for individuals to help them define
the interface between their radio hardware and network controller
hardware that is under development elsewhere. These are
competent and interested engineers, just looking for a little
more coordination and information. If you can help, contact
Tom Kneisel, K4GFG
1600 S.W. 115th Ave.
Davie, FL 33325.
Via FADCA>BEACON
DEMONSTRATION IDEA
If you want to demonstrate amateur radio to the public, why not
try a shopping mall? The South Brevard (Florida) Amateur Radio
Club set up a booth in a local shopping mall, and generated
considerable interest in amateur radio. Packet radio played a
part in this demonstration, with forty-two third-party messages
handled via packet. Twelve of the messages were delivered by the
SOUTHNET packet-radio network, and the rest were passed along to
the All Florida CW Net, part of the National Traffic System.
If you plan a packet demonstration (at a mall or anywhere else)
remember to bring along plenty of backup equipment. The South
Brevard group ran into strong electrical noise on their primary
frequency, but since they had a couple of portable digipeaters in
the mall parking lot, they were able to maintain solid
connections to their message system. Via FADCA>BEACON
TSRAC PACKETS
In keeping with the feeling that Special Service Clubs (SSCs)
should keep up with state-of-the-art technology, several members
of the Triple-States Amateur Radio Club (TSRAC) have been
experimenting with packet radio. Don Knollinger, WB8ZTV, and
Jay, KD8GL, have been communicating via packet, and prompting
their fellow club members to join the "digital communications
wave of the future." TSRAC serves the area where Ohio, West
Virginia, and Pennsylvania meet. Via TSRAC BNT
NEWS FROM ROCHESTER
Fred Cupp, W2DUC, sent us a note giving the details of packet-
radio activity in the Rochester, NY area. Fred says that there
is now an active Rochester packet group with 7 stations on the
air. Thursday night is packet activity night. Look for stations
on the standard EASTNET frequency, 145.01 MHz.
Via W2DUC
MT. ASCUTNEY PACKET CLUB
Another new packet club is the Mt. Ascutney Packet Radio
Association (MAPRA), which serves the area around Mt. Ascutney,
NH. The group's wide-coverage digipeater on 3,000-foot Mt.
Ascutney is now a vital part of the growing EASTNET. For more
information on MAPRA, contact
Carl Breuning, N1CB
54 Myrtle St.
Newport, NH 03773.
Via NEPRA PACKETEAR
NETWORKING IN CALIFORNIA
Packets from Sunnyvale (near San Francisco) were received in Los
Angeles and San Diego this week via several linked UHF repeaters.
The path started on 146.58, went through two UHF hops (duplex
audio repeaters), then out on 144.76, the alternate LA/SD packet
channel. Packets from Oliver Barrett, KB6BA were heard by Harold
Price, NK6K and Sumner Hansen, WB6YMH in Los Angeles, and by Mike
Brock, WB6HHV in San Diego. More experiments are planned for the
near future, including getting some packets up the other
direction. From NK6K
UNIX ON EASTNET
Phil Karn, KA9Q, has connected an IBM PC-XT, running UNIX System
III, to his packet-radio station. UNIX is a powerful, multiuser,
multitasking operating system, and Phil's computer can be
accessed simultaneously via telephone, packet radio, and operator
console. Programs currently available include a satellite
tracking program, mail programs, and a PBBS-style message
facility. In the future, Phil hopes to connect the system to a
TNC capable of supporting several level-2 connections, allowing
simultaneous computer access to more than one packet-radio
station. To use the system as a guest, simply type "guest" in
response to the "login:" prompt, and type return when asked for a
password.
From KA9Q.
MORE INFORMATION ON GRAPES
We have received some more information on the Georgia Radio
Amateur Packet Enthusiast Society (GRAPES). The group is
currently using a 146.13/.73 full-duplex digital repeater
located on Sweat Mountain. The call of the repeater is KD4NC-1.
A PBBS is in the works. GRAPES is running a packet net on 145.54
at 8 P.M., Sundays. The club's address is:
GRAPES
PO Box 223
Conyers, GA 30208.
Via GRAPEVINE
CAPRA MEETING
At its November meeting, the Chicago Area Packet Radio
Association (CAPRA) will present a video tape on level-3 linking.
The video tape was produced by members of the Central Iowa
Technical Society (CITS), following the Iowa Section Technical
Seminar. Lyle Johnson, president of TAPR, and Jeff Ward, ARRL
computer engineer, were the featured speakers at that seminar,
and the video tape should be interesting to those looking forward
to a true amateur packet-radio network. The CAPRA meeting is at
2:00 PM, November 10, in the Glenside Public Library, Glenside
Hts., IL.
Via HAMNET
SOFTWARE AVAILABLE
One of the reasons that packet radio has been able to grow very
quickly is that many technically-skilled individuals have been
willing to donate the fruits of their labors to the packet-radio
community. One of the results of this nonprofit atmosphere is
that packet bulletin board software and TNC software is available
from several sources. Most of this software is in the public
domain, and "sells" for the price of disks or PROMs. Whenever
possible, Gateway will print notes on the availability of public-
domain software for packet radio.
Lynn Taylor, WB6UUT, has written and debugged a very versatile
packet bulletin board system (PBBS) program that runs on Apple II
computers. Lynn's software was designed to be as self-
maintaining as possible and to squeeze every drop of storage out
of two disk drives. It runs under UCSD Pascal, and requires a
TAPR TNC, a Thunderware Thunderclock, a CCS 7710 serial port and
two disk drives. The software is believed to be robust and bug-
free. (As with all free software, however, the user is asked not
to complain if bugs are found.) Lynn is willing to give the
software to anyone who sends him 3 disks and sufficient postage
to return them. Send them to:
Lynn Taylor, WB6UUT
463 Myrtle Street
Laguna Beach, CA, 92651.
If you have a program that you would like to make available to
the packet-radio community, send Gateway a description of the
program.
PACKET RADIO WITH THE XEROX 820
One of the decisions reached at the recent meeting of the ARRL Ad
Hoc Committee on Amateur Radio Digital Communications was that
the Xerox 820 computer would be used as a benchmark and a testbed
for packet-radio networking software. While it is possible to
send and receive packets using the serial I/O (SIO) on the 820,
this job can be done more easily if a high-level data-link
controller (HDLC) chip is added to the computer. In a recent
issue of FADCA>BEACON, Howard Goldstein, N2WX, outlined his
design for such a modification to the 820. After the Digital
committee meeting, Howard and some members of TAPR went to work
producing a kit for this modification. The kit, now called the
"FAD board," is nearing completion; several prototype circuit
boards will be finished by the time you read this. After Howard
tests these first units, the circuit board will be made generally
available. The FAD board is a "piggyback" board that replaces
the Xerox 820 SIO with an 8530 HDLC chip, giving the user two RS-
232-C or TTL HDLC ports. If you are interested in this circuit
board, contact TAPR for ordering information.
From G@WB9FLW
ABSTRACTS
"How Good is Your Network Routing Protocol?," by Hsieh and
Gitman, Data Communications, May, 1984. This article
investigates one of the most important aspects of packet-network
design -- packet routing. There are many routing procedures
under consideration for amateur packet networks, and it is
interesting to read about what the professionals do. The article
addresses route generation, link cost, packet ordering, and
packet-forwarding operation. Two charts detail the routing
strategies used by ARPANET, TYMNET, SNA, DATAPAC, and TELENET,
and the effects that the chosen routing strategies have on those
networks.
"Implementing X.25 Communications Protocol," by Eric L. Beser,
Microsystems, June, October and November, 1984. This series of
articles is a tutorial on X.25, the CCITT packet protocol on
which the AX.25 amateur standard is based. The first article
reviews layered network architecture, and introduces state
machines and their use in protocol implementation. The second
article discusses the design of Pascal software to implement X.25
with the Intel HDLC chips. The third article will discuss
implementation of X.25 using the Western Digital WD2511. If you
are interested in designing a TNC, or just finding out how your
TNC works, read this series of articles.
"RF Modems," by Hatchett and Howell, R. F. Design,
September/October, 1984. This article is the first in a series
of articles covering design and construction of RF modems.
Several amateur groups are currently working on such modems, so
this is a timely article. From the ground up, this first article
addresses the basics of RF modems, system design trade-offs,
types of modulation, and FSK transmitters. It then finishes off
with a discussion of integrated circuits that are useful in RF
modem design. For the experimenter, there is a block diagram and
schematic for a 1.5 Kbits/s FSK modem.
HOW IS GATEWAY DOING?
As this issue of Gateway goes to print, there are more than 200
paying subscribers to the newsletter. Although I have no firm
figures, I am sure that many other packeteers are receiving
Gateway via electronic mail services or amateur packet-radio
networks. I would like to thank you for your support, while
reminding you that Gateway would like to hear from you about
packet activity in your area.
Jeff Ward, K8KA
REPRODUCTION OF GATEWAY MATERIAL
Material may be excerpted from Gateway without prior permission,
provided that the original contributor is credited and Gateway is
identified as the source.
Gateway: The ARRL Packet Radio Newsletter is
published by the
American Radio Relay League
225 Main Street
Newington, CT 06111
Jeffrey W. Ward, K8KA
Editor
Larry E. Price, W4RA
President
David Sumner, K1ZZ
General Manager