dna@dsd.UUCP (David Altekruse) (08/18/84)
GATEWAY: The ARRL Packet-Radio Newsletter
Issue 1
Electronic
WELCOME
Welcome to Gateway, the ARRL packet-radio newsletter. Some
of you reading this are deeply involved in amateur packet radio,
some of you are just getting started on this exciting new mode,
and some of you aren't quite sure what "packet radiolocal VHF
networks will use gateways to connect to an international packet-
radio network. We have called this newsletter Gateway because we
hope that it will, like a gateway station, facilitate
communications between amateurs interested in packet radio.
Gateway will not be a technical newsletter; there are already
several fine packet-radio newsletters covering technical issues.
This will be a "news" newsletter. At ARRL Headquarters we have
many sources of news not all of which are available to each of
you. This newsletter will bring together notes from these
sources. Overseas and domestic packet-radio club newsletters,
the FCC, the IARU, on-line conferences and on-the-air bulletin
boards will contribute. You may see items that you've seen
elsewhere, but you should also see things that are new and
interesting.
Some of you are receiving this packet-radio newsletter and
have never even considered what packet radio can do for you, or
what fun you could have on packet. We hope to provide you with
an overview of the state of amateur packet radio, explaining what
is being done and what can be done on this new mode.
It seems as though every packet-radio club is undertaking
some project that will advance amateur packet radio. To make
these projects fruitful, we must make the most of the limited
resources available to amateurs. By telling a large audience
about various packet-radio development efforts, Gateway should
help organizers direct their efforts, and help volunteers find
the groups that need them.
Perhaps when there is a worldwide amateur packet-radio
network there will be no need for packet-radio newsletters.
Until then, we hope that Gateway informs and interests you.
PACKET METEOR SCATTER
Last weekend's Persieds meteor shower provided a good
opportunity to experiment with packet-radio meteor-scatter
operation. Rich Zwirko, K1HTV, set forth some experimental
guidelines, and stations throughout the U.S. attempted MS QSOs.
On August 1, well before the peak of the Persieds, W0RPK, the
station of the Central Iowa Technical Society, held schedules
with Bob Carpenter, W3OTC, in Maryland. The skeds were on 6
meters. Bob received about 2% of the packets sent from Iowa.
Four nights later, again on 6 meters, W3OTC and W0RPK had what is
believed to be the first amateur packet-radio meteor-scatter QSO.
As the Persieds approached, stations tried their luck on the
2-meter band. Stations in the East included K1HTV; Vern
Riportella, WA2LQQ; Tom Clark, W3IWI; Hank Oredson, W0RLI; and
Mark Wilson, AA2Z. In the West were Ralph Wallio, W0RPK; Bob
McCaffrey, K0CY; Ron Dunbar, W0PN; Mike McQuiston, WA0WYW; Bob
Schiers, N0AN; and Terry Van Benschoten, W0VB. Several of these
stations copied beacons and connect requests via MS. On the
morning of August 12, during the peak of the shower, W0RPK and
K1HTV completed the first packet MS QSO on 2 meters.
Congratulations are in order for all stations involved in these
tests, and I hope that I haven't left anyone out.
These tests were performed at 1200 bauds, using AFSK FM.
While it was necessary to use this mode in order to include as
many stations as possible in the experiments, a performance
sacrifice was made. We should organize further tests at higher
transmission rates with more efficient modulation techniques.
ARRL APPOINTED IARU PACKET CENTER
The ARRL has been appointed IARU packet radio "information
clearing house." The following is exerpted from the minutes of
the IARU meeting in late July: "ARRL is nominated as the
international clearing house of information relating to packet
radio on behalf of the IARU, with a view to encouraging common
standards and regulations."
This points the way toward international understanding and
acceptance of packet radio standards generated in the United
States and Canada. Several European amateurs have hesitated to
get involved in packet radio because they were not sure which
standards would "catch on." The appointment should help to
alleviate this confusion abroad as to what is really happening in
North American packet radio.
PACKET RADIO ON NETWORK TV
On July 16 at 0745 PDT, a packet from N6ECT was heard
throughout the nation on the CBS Morning News show. Curtis
Spangler, N6ECT, was being interviewed by CBS for a piece on the
Haight/Ashbury and the film crew focused on his CRT. As luck
would have it, Curtis was transmitting packets through the KA6M
digipeater. The audio from one of the packets came through loud
and clear, and the frame was heard in all 50 states and
throughout half the world! Via KA6M.
220 MHz and PACKET RADIO
The 220-MHz band is crucial to packet radio for a couple of
reasons. Because it is the lowest frequency band on which we can
exceed 19,600 bauds, it is going to be used for the initial high-
speed intercity linking. It is not being used for any satellite
uplinks or downlinks, and so it is essential for full-duplex
teleport stations. With these considerations in mind, we note
the following:
The Tri-State Amateur Repeater Council has coordinated a 100-
kHz channel from 220.5 MHz to 220.6 MHz for wideband digital
communications. This council coordinates VHF frequencies in
northern New Jersey, southwestern New York (including Long
Island) and Connect This petition calls for the
FCC "to explore the potential use of vacant spectrum in the UHF
TV bands, spectrum allocated for Fedral Government use, or
assignments from the band 220-225 MHz to satisfy the requirements
of land mobile users." This may sound worse than it is, since
the petition goes on to say "Because of the limited number of
channels that the 220-225 MHz band will provide, however, it is
not anticipated that this spectrum can meet the immediate
requirements of land mobile licensees."
Another petition (RM 4831), from a manufacturer of amplitude
compandored sideband equipment, explicitly requests reallocation
of the band 216-225 MHz. This petition poses a serious threat to
the 220-MHz amateur band.
Packet radio needs the 220-MHz band. Be sure to read these
petitions and send your comments to the FCC. The comment
procedure was outlined in QST, March, 1982. The comment deadline
for these two petitions is August 29, 1984.
WHAT'S BREWING AT TAPR?
This piece came from Harold Price's answer to the question
"Is TAPR up to something?" Harold is part of the TAPR software
design team, and he made these comments while he was "Member of
the Month" on Compuserve's HAMNET.
"The following views are mine alone, and do not necessarily
refect those of TAPR, AMSAT, VITA, LAPG the staff, management, or
janitorial departments.
"The TAPR folks are indeed up to something. We have the
TAPR Pascal code running happily under a simulated environment
again. The software, with only one change, runs under TURBO
Pascal on the Pronto-16. This will vastly speed up development,
which has slowed down as of late.
"The plan is to come up with version 4.0 of the TAPR TNC
software which will allow testing of both datagram and virtual
connection protocols. I think the level two wars are over. With
1300 TNCs in the field from 6 "manufactuers" all running the same
level two, anyone proposing a switch now is just rocking the
boat. The few proposals I've seen for different level twos offer
no concrete advantages over what we've got now anyway. Besides,
level two is boring (now that we have one that works). The real
fun is level three.
"For the newcomer, level two refers to a point to point
protocol, linking one TNC to another with no TNCs in the middle.
There is currently a necessary kludge in AX.25 called digipeating
which is a very demented level three feature. Digipeating allows
two TNCs to be connected using a third as a relay. Without this
simple addition to AX.25, packet may not have taken off as it
did, since digipeating allows many more users to reach each
other. If you haven't got a wide-coverage duplex repeater (or
even if you have), digipeating is your best bet for now.
"Anyway, level two is point to point, with level two+ in
current style, multihop dumb repeating. The + in level two will
die a happy death when we get level three up and running. Level
three links two end points thru multiple intermediate TNCs. The
linking is done in an intelligent manner. ACKing is node to node
rather than end to end. In level two digipeating, each
intermediate point simply regenerates the packet. It does not
ACK it. The final end point ACKs it, and the ACK is blindly
repeated back to the starting point. If any repeat of the
packet, or the ACK, is stepped on or dropped, the packet must
start over from the beginning.
"In level three, an ACK can occur at each step of the way.
Thus, a packet may only have to be re-sent between relay points
five and six, rather than starting again at point one. So why
don't we get on with it, you might ask?
"There are many problems involved in design and
implementation of a level three network -- flow control, network
blocking, routing, on and on. What is TAPR doing?
1) A node in a level three network will want to be
connected to more than one other node. We will allow the TAPR
TNC to maintain multiple level two connects. This has several
implications. First, you can carry on two or more concurrent
conversations. Not so good for rag chewing maybe, but great for
emergency communications. Imagine a TNC in the local disaster
center. Currently you can carry on a conversation with only one
other TNC, with limited possibility of a priority break-in from
another TNC. With all outlying TNCs connected to the central
node at the same time you get closer to what you want, high
reliability connections with each of the field guys at the same
time.
"Next, and even better, you can automatically route one
connection stream to another. Maybe an example is called for.
The syntax below is probably not what we'll end up with, but the
idea is:
MYCALL NK6K
[1] CONNECT WB6YMH
[1] CONNECTED TO WB6YMH
[2] CONNECT WA6JPR
[2] CONNECTED TO WA6JPR
ROUTE [1] TO [2]
"Your TNC is now a network node. Anything that comes in
from stream [1] gets ACKed at level two. The data from the
packet gets routed to stream [2] where it gets sent out and saved
until an ACK comes in on stream [2]. The reverse is also true,
incoming from [2] goes to [1].
"Now, wouldn't it be great if you could cause the other guys
board to make a connection? If I could tell WA6JPR to make a
level two connection to WB5EKU? Then what we have is the level
three function, endpoints linked thru multiple intermediate
points. A lot of things are missing, but this simple mechanism
allows testing of level three concepts without a lot of hassle on
the users part. We will also design an interface (based on
asyncronous LABP) between the TNC and its attached computer to
allow the computer full control over the link process. This
permits the use of the TAPR TNC as a level two black box, with
level three functions done in your host.
"Do I expect everyone to run verson 4? Well, why not?
Version 3.1 can still be used point to point, and thru 4.0
gateways get full access to network. But just as everyone having
the capability of being a digipeater added to the swift growth of
packet, so will the ability of each TNC to be a level three node.
"But I ramble. Not only does a network node need to support
multiple level two connections, it might also need to support
connections on multiple RF channels. Let's assume a 1200-baud
link on 2 meters and a 2400-baud link on 220, feeding a 9600 baud
link on 440. The hardware arm of TAPR is designing a fancy
multiport hardware controller. Several designs have been
proposed, including a motherboard with slots for plugging in a
number of channel-controller cards. Each channel-controller card
is a mini TNC, handling all channel-access and level two
functions. The mother board passes data between channels and
handles level three and higher functions.
"We don't expect everyone to have one of these TNC-LINKs
(say "tink link"). But they will make great mountain-top
controllers, especially when used with the PACSAT 9600 whiz-bang
modem, which has been described elsewhere.
"How long do I see TAPR building kits? There are two
answers: "As long as there is a demand" or "Until we can't stand
the sight of them anymore." I haven't been pressed into the
chain gang of kit packaging, but isn't much fun, especially when
serial number 1000 has long since gone out the door. The kits
are TAPR's only source of income. An extremely small amount of
each $240.00 goes into our fund for future development. I have
forgotten how much. A number that does come to mind is the cost
of the cabinet kit. Your cost, $69.00, our cost, $67.00. Our
original goal was to make packet available to a large number of
people at reasonable cost, delivering as full a function device
as we could. It is possible to deliver less function for less
cost. It is possible to deliver the same function assembled,
tested, and warranted, for a larger cost. There are several
market niches out there, and we will continue to ship as long as
1) there is a niche for us and
2) we're having a good time.
"Are we having fun yet? You bet!
"One final note. A for-profit company would be crazy to
discuss future products like this before the product is ready to
ship. But we're a nonprofit R&D company, trying to make packet
the mode of the future. And remember, you saw it here first."
Via HAMNET.
Club Listing
Here is a list of clubs active in Amateur packet radio.
Amateur Radio Research and Development Corp. (AMRAD)
P.O. Drawer 6148
McLean, VA 22106-6148
Amateur Radio Satellite Corp. (AMSAT)
P.O. Box 27
Washington, DC 20044
Chicago Area Packet Radio Association (CAPRA)
P.O. Box 8251
Rolling Meadows, IL 60008
Central Iowa Technical Society (CITS)
c/o Ralph Wallio, W0RPK
Rural Route 4
Indianola, IA 50125
Florida Amateur Digital Communications Assn. (FADCA)
c/o Ted Huff, K4NTA
1829 N. W. Pinetree Way
Stuart, FL 33494
Los Angeles Area Packet Group (LAPG)
c/o Harold Price, NK6K
1211 Ford Ave.
Redondo Beach, CA 90278
Minnesota Amateur Packet Radio (MAPR)
c/o Philip S. Plumbo, N0DF
San Diego Packet Group (SDPG)
c/o Mike Brock, WB6HHV
10230 Mayor Circle
San Deigo, CA 92126
Tucson Amateur Packet Radio Corp. (TAPR)
P.O. Box 22888
Tucson, AZ 85734
Vancouver Amateur Digital Communications Group
(VADCG)
9531 Odin Road
Richmond, BC V6X 1E1
CANADA
Remember to include an s.a.s.e when writing to any of these
clubs. Club money spent on postage is money that can't go into
packet-radio development.
We also know of the following individual who would like to form a
packet-radio club:
Doug Baker, K4CLE
8724 Cumbernauld Circle
Germantown, TN 38138
U.S. AMSAT
Thu 2000 EDT 147.12/72 Boston area NEPRA
Sun 1900 UTC 14.235 National TAPR
Sun 2100 UTC 7.158 National TAPR
Sun 0800 EDT 3.958 Regional FADCA
Sun 1900 EDT 147.165 Tampa area FADCA
Sun 2100 EDT 147.285 Orlando area FADCA
Sun 1500 CDT 7.158 Central U.S. CITS
Gateway: The ARRL Packet Radio Newsletter is
published by the
American Radio Relay League
225 Main Street
Newington, CT 06111
Larry E. Price, W4RA
President
David Sumner, K1ZZ
General Manager
Jeff W. Ward, K8KA
Editor
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