karn@petrus.UUCP (01/02/85)
Message: 511: GATEWAY: 12-18 to: ALL from: K8KA
Filed at: 12/18/84 18:49
Gateway: The ARRL Packet Radio Newsletter
Volume 1, Number 10
December 18, 1984
Season's Greetings!
ATTENTION GLB DIGIPEATER USERS
If you are using a GLB PK-1 primarily as a digipeater, you
should immediately get a software update from GLB. Software
prior to Version 3.5 will not digipeat multiple frames with
multiple digipeaters. If a GLB PK-1 is specified as part of a
multirepeater path, only the first frame in any transmission will
be repeated. This can exponentially increase the traffic on a
channel where a PK-1 is a wide-coverage digipeater.
To get your software updated to Version 3.5, send a $10 deposit
(or your current PROMs) to GLB. When you receive your new PROMs,
send the old ones to GLB and you will get your deposit back.
This is an important problem, and should not be ignored by GLB
users. The GLB address is
GLB Electronics
1952 Clinton St.
Buffalo, NY 14206.
From GLB.
MORE FROM GLB
In Gateway issue 8, we reported that GLB electronics, makers of
the PK-1 TNC, were at work on the PK-2. Ed Jackson, an engineer
with GLB, was able to confirm that preliminary engineering work
is being done on the PK-2, but that it is primarily a "commercial
TNC." More important for the radio amateur is GLB's development
of the PK-R, an integrated VHF radio and TNC. On the RF end of
the PK-R is a 25-watt crystal-controlled, highly stable FM rig.
The packet equipment is a PK-1 TNC. For repeater operation, you
simply connect the PK-R to a 12-V supply and an antenna, hit the
reset button and you're on the air. For home-station use the rig
has an RS-232C connector that goes to a terminal or computer.
The PK-R is ready for type-acceptance tests, so look for it on
the market before long.
Mr. Jackson also reports that a 200-Hz shift modification for the
PK-1 is almost complete. This, along with an existing 300-bit/s
modification will allow PK-1 users to join the growing number of
HF packet users.
Ed.
TWO-METER BAND PLANNING
In several metropolitan areas, the amount of packet-radio traffic
has exceeded the capacity of a single 1200-baud channel. On the
east coast, the channel that is full is 145.01 MHz, and one of
the most-asked questions is "what frequency do we go to next?"
This question has no simple answer.
Ultimately, packet radio will move up to and above 220 MHz. When
intercity "backbone" links are running on 220 MHz, the congestion
on 2 meters will be eased. However, even when the network
backbone is in place and experienced packet operators are moving
to higher transmission speeds on higher frequencies, local
traffic and "entry-level" packet operation will be on 2 meters.
So, the question remains: What frequency do we go to next? Some
people on EASTNET have proposed a 20-kHz channel spacing, using
145.010, 145.030, 145.050, 145.070 and 145.090 MHz. Albert
Hamilton, AG1F, Chairman of the New England Spectrum Management
Committee points out that "Any rig produced in the last 6 years
is perfectly capable of operating on a 15-kHz spacing without
undue problems. While there are some real pieces of junk
operating on 145.010 MHz now, that is no reason to give up
sensible spacing." Using a 15-kHz spacing would provide six
channels between 145.000 and 145.100 MHz -- one more channel than
could be provided with 20-kHz spacing. We may need this extra
channel in a few years.
If packet activity in your area is beginning to move away from a
single 2-meter frequency, consider the arguments for a 15-kHz
spacing. If you have any comments on this topic, address them to
Gateway and
Albert W. Hamilton, AG1F
Chairman
New England Spectrum Management Committee
54 Hathaway Ave.
Beverly, MA 01915.
Ed.
RTTY-TO-PACKET GATEWAYS
Albert Hamilton, AG1F, who made the above suggestions concerning
band planning, is also interested in working on a RTTY-to-packet
gateway. Ideally, such a gateway would operate in real-time,
allowing the RTTY user and the packet user to have a proper
contact without knowing what mode the other operator was using.
An alternative to this scheme would be to have a bulletin-board
system that could be accessed by both packet and RTTY stations.
Since there are already many stations equipped for Baudot RTTY,
packet-to-RTTY gateways could bring interested amateurs in
contact with packet radio while increasing the utility of packet
networks for traffic handling.
If you have undertaken a packet-to-RTTY project, send the details
to Mr. Hamilton and Gateway.
From AG1F.
PACKET IN PENNSYLVANIA
Gary Hoffmann, AK3P, sends us a summary of packet activity in
central Pennsylvania. Gary got his TAPR TNC in June, and was the
first station on the air in the Harrisburg, PA area. Shortly
after that, Bob Warrington, WB3FQL, and Tim Shingara, WB3EYB,
were also in operation. Tim supplied a link to WB4APR near
Balitmore, and the group gained access to EASTNET.
In October, Gary installed a wide-coverage digipeater above
Harrisburg in the building of the Central Pennsylvania Repeater
Association. The digipeater, running under the call WA3KXG, is
in operation 24 hours per day, on 145.01 MHz. From its 1400-foot
elevation, WA3KXG provides a reliable link into Baltimore,
Washington, and Virginia, via WB4APR and W3VD. A link into New
Jersey has been established through WB3FYL and W2FPY.
There are presently about 5 stations on packet in the Harrisburg
area, all using TAPR TNCs. Gary hopes that activity will
increase in the near future, with links established into
Scranton, PA and New York state.
Another item from Pennsylvania: Neil Sablatzky, WA2WIM, in
Edinboro, PA (near Erie) is interested in becoming active on
packet. His problem is that no one else in his area is
interested. He would like to help link Northwest Pennsylvania
with the eastern and southern parts of the state. He would also
like to establish some contacts into the Buffalo, NY area. Neil
would like to hear from anyone near Erie who is working on packet
networking. He can be reached on the WB3USH repeater on 146.76
MHz, where he will be listening on packet when his TAPR TNC
arrives. You can write him at:
201 Granada Drive
Edinboro, PA 16412.
From KC2WZ and AK3P
MIDWEST NETWORKING
The packet-radio network that has grown up around central Iowa
has finally reached the Iowa-Minnesota border. Lyle Monson,
W0FQ, is active from Spirit Lake, IA.
Lyle wants to know what frequencies are being used in southern
Minnesota, and is looking for some active stations to hold
schedules with. He will be able to connect to the rest of the
Iowa packet network via W0ZVY, the wide-coverage digipeater in
Guthrie Center, IA.
The Central Iowa Technical Society (CITS) is planning a 220-MHz
intercity network. They are looking for a station around Mason
City, IA to extend this backbone to the north.
From W0RPK.
MT. BEACON DIGIPEATER
The gaps in EASTNET are beginning to be filled in. The addition
of the WB2KMY digipeater on Mt. Beacon, NY will help to tie both
Boston, MA and Newington, CT into the southern portion of the
network.
The Mt. Beacon digipeater, on 145.01 MHz, is the first part of an
ambitious project being undertaken jointly by the Mt. Beacon
Amateur Radio Club and the Putnam Emergency Amateur Repeater
League (PEARL). When the project is complete, there will be two
complementary digipeaters in the mountains around Poughkeepsie,
NY. One of the machines will be on Mt. Beacon, a site that has
good coverage to the west. The other will be on Mt. Ninham, with
a clear path to the east. The two clubs will be working together
to minimize interference between the two digipeaters maximize
the coverage provided by the pair.
The call used at the Mt. Beacon site is WB2KMY-1, and the call at
the Mt. Ninham site will be KG1O-9. If you are located in
northern New Jersey, Northeastern Pennsylvania or Western New
England, check out these new facilities. (Leave reports of
coverage on the WA2RKN-2 MailBox.)
If you are not in New England, there is still something of value
here; packet repeaters, unlike 2-meter voice repeaters, must
coexist on a single frequency. If several clubs in one area are
interested in packet radio, it is important that they work as a
team to provide valuable and useful coverage. Lack of
cooperation can only lead to a congested local-area network.
Via WB2KMY.
WESTNET IN MONTEREY
Packet operations in Monterey, CA, have improved due to the
addition of a 6-element Yagi at the K6LY digipeater site. Buzz
Shaw, WA1NHP, reports that the Monterey packet operators are also
looking into a site on Mt. Toro, at an elevation of 3500 feet.
This would be a real improvement over the current site, which is
only 110 feet above sea level. However, even at the low
elevation, stations using K6LY can usually connect to Hank
Magnuski, KA6M, and use his Data General computer system.
Via WA1NHP
ILLINOIS PACKET MEETING
Twenty-five people, representing networks in Central Illinois,
Southern Illinois, Chicago and St. Louis, attended the December 2
meeting of the Central Illinois Packet Radio Users Society
(CIPRUS). The administrative portion of the meeting resulted in
a statement of the club's intent "to promote packet radio
throughout Illinois by acting as a clearing house for packet
information, and to work for reliable packet communication within
Illinois."
After electing club officers, those present took up a discussion
of packet-radio operating practices. Since packet radio is new
to amateur radio, there is no body of common thought as to what
constitutes "good operating procedure." In particular, there is
still no agreement as to when it is appropriate to send out CQ or
QST messages. Broadcasting such frames through wide-coverage
digipeaters has started to significantly slow traffic on several
crowded networks. However, those at the CIPRUS meeting agreed
that QST packets used as propagation indicators or to carry news
bulletins were reasonable. They also decided that CW
identification is not necessary and should be discouraged.
[Close examination of section 97.84 of the FCC Amateur Radio
Service Rules shows this to be an acceptable decision.-- Ed.] It
was observed that application of common sense by packet operators
would significantly reduce network congestion.
The CIPRUS meeting closed with the distribution of the the
national Packet User's Directory as compiled by N9AGC and
available through CIPRUS.
Via K9NG.
PACKET MAP
Paul Barnett, N0CRN, placed the following message on DRNET:
"I'm compiling information on existing amateur packet networks to
use at an upcoming packet-radio demonstration. I want to be able
to show a large map of North America that is sufficiently
detailed to explain multiple digipeaters and show how packet-
radio networking is progressing.
"I would like everyone to send me information about their local
network, so that I can generate the map. Please confine the
listed stations to those with wide coverage. I'm not
particularly interested in the 50 stations within 25 miles of
each other in a metropolitan area. What I am interested in is
the stations that make up a link into another metropolitan area.
"I'd like to hear about all forms of networking: VHF (EASTNET,
SOUTHNET, WESTNET), HF (particularly gateways and scheduled
traffic handling operations) and OSCAR teleports.
"Confine your descriptions to reliable links, noting those that
are not available 24 hours per day. Please limit information
about planned links to those that will be a available by the end
of the year.
"When I get the map done, I will try to reduce it to a single
page and make it generally available.
Send information about your local network to
Paul Barnett, N0CRN
130 Demont Ave. East, Apt. 255
Little Canada, MN 55117
or to Gateway at the ARRL.
Via DRNET.
PACKET APPLICATIONS: WEATHER
K6AAG>QST:HIDESERT WX 1100/52/SCTRD/VIS10HZ/SSE10-
15/29.71/"Robbie"
Although running in an attended and manual mode now, the above is
an example of what could become an automated service as packet
radio continues to grow and rules continue to change.
For those who need help in interpretation (as I did), the above
QST frame says that the weather in Southern California's high
desert region at 11:00 was 52 degrees, scattered clouds,
visibility 10 miles with haze, winds from the south southeast at
10-15 knots, barometer 29.71 inches. Robbie Wohosky, K6AAG, the
originator of the message, is active in the California weather
net on 75 meters. He currently summarizes the information
gathered by this net and distributes it via RTTY. He is now
looking into ways to use packet radio as well.
It is probably a safe bet that amateur-gathered weather
information will be part of the data stream as regional and
national digital networks take shape.
[If you have thought of any interesting applications of packet
radio, please send them along to Gateway. -- Ed.]
From NK6K.
PACKET READING
Paul Newland, AD7I, points us toward IEEE's Communications
Magazine, an IEEE monthly publication that features tutorial
technical discussions about communications concepts and systems.
(Don't confuse it with IEEE Transactions on Communications, a
mathematical and theoretical journal.) The December issue of
Communications Magazine contains the following articles of
interest to packet-radio enthusiasts:
"Automatic-Repeat-Request Error-Control Schemes," by Shu Lin,
Daniel Costello, Jr., and Michael Miller. Error detection
incorporated with automatic-repeat-request (ARQ) is widely used
for error control in data communications systems. [Including
packet radio. -- Ed.] This method of error control is simple and
provides high system reliability. If a properly chosen code is
used for error detection, virtually error-free data transmission
can be attained. This paper surveys various types of ARQ and
hybrid ARQ schemes, and error detection using linear block codes.
"Improving on Bit Error Rate," by Virgil I. Johannes. On the
semantics of the term -- its invalidity in the absence of a
specified averaging period.
"Digital Signaling Techniques," by William Stallings. A
comparison of various encoding techniques with an eye to superior
performance.
Also look into the November, 1984 issue of Proceedings of the
IEEE. This special issue on satellite communication networks
contains an article titled "Packet Switching for Mobile Earth
Stations via Low Orbit Satellite Network." Remember, PACSAT is a
low-orbit packet satellite.
R.F. Design magazine for November/December, 1984 contains the
conclusion of a series called "RF Modems." This article
addresses the design and use of frequency agile modems. Several
block diagrams and schematics are presented.
The December, 1984 issue of Telecommunications is a special issue
on data communications systems, and contains several articles
that packet experimenters might find interesting.
Via AD7I, KA9Q, Ed.
MISSING GATEWAY
When you subscribed to Gateway, you probably subscribed for 25
issues. A few quick calculations will tell you that there should
be 26 issues in a 52-month year. The missing issue is to allow
me to take some time off around the New Year. Therefore, there
will be no Gateway dated January 1, 1985. Look for Gateway issue
11 on January 15. I hope that you all have safe and enjoyable
holidays.
Jeff Ward, K8KA
REPRODUCTION OF GATEWAY MATERIAL
Material may be exerpted 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