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Publications:

ARRL 12th DCC Proceedings 1993

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This proceeding is available on CD-ROM


Location:
Tampa, Florida

Coordinator:

Hosted by:
TPALAN

Abstracts:
12th Digital Communications Conference
September 11, 1993

Using Airborne Digital Repeaters in Emergency Communications
by Gary Arnold, WB2WPA
Introduction: The state of Florida is, as pointed out so dramatically on August 23-24, 1992, vulnerable to the destruction of a hurricane. Communications links so vital to recovery are often among the weakest, most vulnerable tarqets. Linking the southern half of the state with the state capitol in Tallahassee is more than difficult, because of the distances involved (Figure 1). On the southwest coast of Florida in Naples, 110 miles due west of Ft. Lauderdale, the Collier County Emergency Operat-ions Center provides link from EOCs up the west coast to Dade, Broward and Monroe Counties, including the National Hurricane Center in Coral Gables, Florida. A dual port network node is located at Ochopee providing 220 and 440 links to the east coast. Another is planned for a federal government site near the Dade County line, providing redundant sites along US 41 between Naples and Miami.

Proceedings Paper



A Prototype TNC-3 Design Approach
by Bill Beech, NJ7P, Doug Nielsen, N7LEM, and Jack Taylor, N7OO
Abstract: Many TNC design proposals have been advanced over the years. However, with few exceptions, the venerable TNC-2 and it's clones still proliferate the marketplace. Factors influencing this situation include: (1) A very cost-competitive market between various entry level models. (2) Proprietary operating software that has tended to stifle TNC development. This paper describes a design philosophy that the authors believe will lead to the next generation TNC.

Proceedings Paper



DSP Implementation of 300- and 1200-Baud FSK Packet Demodulators
by Jon Bloom, KE3Z
Abstract: This paper gives the theory of operation for a DSP implementation of 300- and 1200-baud FSK modems. Specific algorithms are described and filter characteristics are given for an actual implementation.

Proceedings Paper



The ARDS Project
by Roy V. Ekbert, W0LIQ, and Martin R. Schroedel, K9LTL
Abstract: ARDS is an acronym for Amateur Radio Data Syntheses. Three kinds of systems can be synthesized: manual, computer-aided, and automated. We have only tested models of the first two via using simulation. Meanwhile, we're awaiting permission from the F.C.C. to try over-the-air tests. Part 97 amateur radio rules forbid secrecy. A secrecy waiver is necessary because ARDS' radio signals cannot be deciphered without ARDS systems. This paper reveals how computer- aided systems work and how they can supplement ham communications.

Proceedings Paper



Usage of TCP/IP Over ROSE in the Tampa Bay Area
by Chuck Hast, KP4DJT/TI3DJT
Abstract: With the usage of NOS in the Tampa Bay area, we have found the need to link between NOS users using the ROSE network. Like other areas where ROSE is used as the primary networking system, up until a year ago, the only way to do so was using SLIP over TNC's running in transparent mode. Manually setting up the link then issuing the slip connection to the distant IP facility.

Proceedings Paper



Unique Identification Signals for CCIR 625
by Michael J. Huslig
Abstract: When an AMTOR master (CCIR 476) calls an AMTOR slave, it uses a 4-character identification. Since the AMTOR alphabet is based on the RTTY code, these four characters can only be uppercase alphas [A...Z]. But an amateur call sign can be from 3 to 6 characters, of which at least one is a number. The amateur community is using some workable algorithms to map callsigns to these 4 characters; unfortunately there is no way to map these 4 characters back to a unique callsign.

When CCIR 625 was added to AMTOR, the number of identification signals expanded to 7. However, because of a checksum calculation that is used during the initial connection, the 7 characters can only be a subset of the uppercase alphabet. Because the checksum uses a modulo-20 addition, only 20 alphas can be used out of the 26.

Proceedings Paper



Network Information Services
by Brian A. Lantz, KO4KS
Introduction: In the early days of packet radio, you were lucky to find a station or two that you could connect to for a digital QSO. As time has progressed, BBSs took the role of "generic information providers", with bulletins, and E-Mail as their strengths. Current BBSs are used nearly 100% for message handling. The BBSs have a distinct weakness in the area of providing information to the user. The two main ways that BBSs provide generic information are: 1) Requiring the user to read certain messages 2) Requiring the user to download certain files. Both of these provide a learning hurdle to a new user, which will probably cause the user to try to "stumble through it" without the needed information.

ROSE (and other networking tools) have taken the first steps of network information services by placing a screenful of text in the memory of the switch/node to answer a few questions the user might have. This is made simple for the user, requiring him to connect to an alias; no new actions to learn.

The average new user has limited computer experience and very probably NO experience with other E-Mail systems. Networks are a concept that scares even many long-time packeteers. An information provider should take these into account and also provide a way to be interactive, at least to a point.

Proceedings Paper



Networking ANSI Color Graphics
by Brian A. Lantz, KO4KS
Abstract: A typical network supports two kinds of users; regular users and super-users. The regular users provide the NEED for the network. Without those who wish to USE the network, the network is useless! It doesn't matter if it is ROSE, NETROM, TCP/IP, or SplatRouter-200(); if there are no users, there is no need. The second class of users, super-users, try to MEET the needs of the regular users. There are usually BBSs, but can also be information providers, Interret mail routers, non-radio wormholes to distant places, and any other resources that might be needed or desired. While both classes of users should he given equal status pertaining to the use of network resources, the regular users, obviously, should he given special consideration. Their needs and desires should be constantly evaluated by the local administrators of the network, as well as by the writers of packet software.

The users in the early days of packet, the users had low expectations, since this was all a new experience. The users of 1993 have developed a desire to do more. They want new capabilities. They want to be able to do things more like landline networks. This brings us to ANSI color graphics. This paper will hrietly descrihe the needs, the shortcomings, the facts, and the solutions to making our networks support ANSI color graphics.

Proceedings Paper



Interfacing Between ROSE and TCP/IP
by Thomas A. Moulton, W2VY
Abstract: The goal of the RATS Open System Environment (ROSE) X.25 Packet Switch from the beginning was to develop a radio network based upon standard protocols. It was also required that it provide reliable and completely transparent communications to all users of the AX.25 protocol. For over a year now ROSE has properly supported passing AX.25 frames of any protocol type (PID). This was just the first step taken by ROSE in providing fully transparent services to TCP/IP users.

Proceedings Paper



Packet Radio in Disaster Situations
by Robert Osband, N4SCY
Abstract: Packet Radio, a mode of data communications over amateur radio frequencies, was seldom used during communications operations following Hurricane Andrew. This paper will detail the situation as found by a user who went there to help, and proposed suggestions for future disaster recovery packet radio operations.

Proceedings Paper



The HUB 5/29 IP Routing Experiment
by Paul Overton, G0MHD, and Ian Wade, G3NRW
Abstract: This paper summarises the disadvantages of default IP routing, which often leads to total traffic loss when attempting to forward over lon~ distances. This is followed by a description of how to set up a hub routing scheme that overcomes these problems. An experimental scheme along these lines has been successfully implemented in Regions 5 and 29 in the UK (hence the Hub 5/29 in the title of this paper).

Proceedings Paper



A Low Cost Transceiver for 19.2 kb/s FSK Transmission in the 23 cm Band
by Wolf-Henning Rech, N1EOW/DF91C
Abstract: Why 23 cm ? Why not ? Yes, it is well known that many packeteers become quite unsure when they see a circuit diagram full of obvious short circuits (some people call them strip lines) connected to parallel capacitors - what a nonsense ! And why to use even discrete transistor stages instead of the fine HCMOS inverters ? Speaking about microwave transmitters finally cause the complete panic, and everyone assures that he has nor a lathe neither a network analyser at hand. But, don't panic! 23 cm isn't yet so exotic as you may think perhaps. A lot of good semiconductors and other components are available at low prices, and with a well-designed printed circuit board the assembly is nearly as easy as for a TNC. Yes, there are some special rules to care, but they are few and simple.

Proceedings Paper



Low Cost Entry Into Packet Radio Using BayCom
by Christopher C. Rendenna, KB2BBW
Abstract: This paper picks up where last year's topic, "Low Cost Entry Into Packet Radio Using Digicom" (11th ARRL Computer Networking Conference) left off. Its purpose is to acquaint the beginner or experienced packet user with the versatile BayCom Modem as well as providing information on setting up a low cost packet radio system via the BayCom modem and software. It assumes the reader is minimally computer literate and has a basic knowledge and understanding of packet radio basics.

Proceedings Paper



Improved TNC Interconnections
by Donald A. Rotolo, N21RZ
Abstract: Hardware for interconnecting TNCs to form a TheNET or ROSE network hub has been further refined for greater convenience. An updated version of the well-known Diode Matrix Boardfor RS-232 network hub backbones is introduced. The new board has been re-packaged into a bacic land-line configuration, eliminating the need and expense of cables for the RS-232 signals. Additionally, a new circuit is described which allows multiple TNCs to be interconnected at high speed via their modem disconnect headers, with fullflow control, using only two signal wires.

Proceedings Paper



Packet Tracker - A Graphical Packet Tracking Program
by Mark Sproul, KB2ICI
Abstract: Packet Radio is a very interesting and growing part of Amateur Radio. For the new person investigating Packet Radio, there are many things to be learned and lots of different aspects of Packet Radio that will not be grasped for a long time. Even the advanced Packeteer usually does not understand everything going on with Packet Radio. If someone wants to know what kind of Packet services and what BBS's or other activity is going on in their area, they are usually told to hook up their TNC and put it into MONITOR mode to see what is going on. This process will give them screen after screen, day after day, of almost un-intelligible garbage flying across their screen. Unless they take the time to start writing down call signs and understand some of the different protocols, they will be COMPLETELY lost and confused.

Packet Tracker is a program that monitors that stream of 'garbage' and presents a graphical representation of all of the different conversations occurring on the frequency at one time. It does this by showing icons representing the different stations and draws lines from one station / icon to another representing who is talking to whom. It also shows where retries are happening and who was the most recent person to actually transmit and how many packets were transmitted by each station. Packet Tracker also keeps track of lots of statistics about the activity of each station and also statistics about actual band, usage.

Proceedings Paper



Mail Tracker - A Graphical Mail Tracking Program
by Keith Sproul, WU2Z
Abstract: Packet Mail Forwarding as we know it today works pretty well. [1] The end user enters a message into the system and, other than having to address it correctly, he does not have to do anything else to make it get to its destination. If the message is addressed for some place local, it is handled via VHF only. If it is addressed for someplace far away, it gets routed to the appropriate 'gateway' to get it there. This gateway might be an HF gateway, or a SATELLITE gateway, or a WORM-HOLE, but somehow, the system knows or thinks it knows the best way for a message to get from where it is currently to where it should be. There has been much discussion on routing methods, automatic updating of routing tables, and on the best way to route messages. This can be an extremely volatile topic of discussion and will not be discussed here. This paper discusses a network utility program called MAIL TRACKER that will look at messages and graphically show the route those messages have taken from the point they entered the network to their final destination. This paper will not discuss how to route traffic, only how to evaluate the routings being used.

Proceedings Paper



The Client/Server Bulletin Board System (csbbs)
by Jim Van Peursem, KE0PH, and Bob Arasmith, N0ARY
Abstract: The current Bulletin Board System (BBS) network is showing signs of age. There are problems with duplicate messages, new users are intimidated by their interface, the channel is becoming congested, etc. By looking at the underlying assumptions of the current systems, significant improvements can be made. Some of them require substantial changes, but the benefits far outweigh the trouble involved. This paper looks at a client/server architecture currently being developed by NOARY, KEOPH, WB6YRU, and N6ZFJ, called the csbbs (client/server bbs). The paper describes the goals of the new system, and some of the ideas being considered.

Proceedings Paper



RMAILER: The Next Generation
by Frank Warren, Jr., KB4CYC
Abstract: At the Eleventh Computer Networking Conference, RMAILER an add-on server for the remote ad hoc mailing list protocol known as RMAIL (Remote MAlLer) was introduced. RMAILER has evolved since that time taking some at times interesting turns in development.

Proceedings Paper



SoftWire
by Aaron Wohl, N3LIW
Abstract: SoftWire is a system for designed schematics using digital logic. The schematics are translated into assembly code for a target microprocessor.

Proceedings Paper



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