This proceeding is available on CD-ROM
- Seattle, Washington
- Steve Stroh, N8GNJ
- Keith Justice, KF7TP
- Steve Ford, WB8IMY
- Greg Jones, WD5IVD
- Keith Justice, KF7TP
- Hosted by:
- Puget Sound Amateur Radio TCP/IP Group
- Boeing Employees Amateur Radio Society (BEARS)
Read the conference story with audio and photos.
15th ARRL and TAPR Digital Communications Conference
September 20th, 1996
- Learning DSP by Porting Programs to the TAPR/AMSAT DSP-93 Modem
by John Bandy, W0UT
- Introduction: This paper is about porting assembler programs in the text authored by Rulph Chassaing and Darrell W. Horning, titled, "Digital Signal Processing with the TMS320C25," to the TAPR/AMSAT DSP-93. Porting these senior/1st year graduate electrical/computer engineering student level programs taught the author many things about digital signal processing (DSP) in general and TAPR/AMSAT DSP-93 modem in particular.
- Linking BPQ Switches via Ethernet
by Bill Barnes, N3JIX
- Abstract: Two or more computers, running G8BPQ node software, can be linked using Ethernet with the BPQ driver for ODI. This paper discusses the process and outlines the setup files required.
- javAPRS: Implementation of the APRS Protocols in Java
by Steve Dimse, KO4HD
- Abstract: This paper describes a implementation of the Automatic Position Reporting Systems (APRS) protocols in the computer language Java. javAPRS extends the usefulness of APRS to the Internet.
- The Radio Amateur Digital System Artificial Intelligence Project
by Garry W. Joerger, N5USG
- Abstract: This paper outlines information on the Radio Amateur Digital System Artificial Intelligence Project from it's conception to current capabilities and ongoing development. The applications chosen for this paper are intended to support amateur radio, weather service, emergency management and ultimately the public.
- Fast Flow Control in High-Speed Communications Networks
by C.M. Kwan, R. Xu, and L. Haynes
- Abstract: A new approach to flow control in high speed communication networks is proposed where the flow control problem is modeled as a dynamic system with time delay. The main advantage is that it can assure stability of system as well as maintaining certain throughput of the communication channel. Inside the controlled, there is a term which predicts the future backlogs in the system. The controller is easy to implement. Simulation results show that the method offers significant less delay than existing methods.
- Nonlinear Channel Equalization Using Fuzzy CMAC Neural Network
by C.M. Kwan, R. Xu, L. Haynes, and J.D. Pryor
- Abstract: It is well known that nonlinear distortion over a communication channel is now a significant factor hindering further increase in the attainable data rates in high-speed data transmission. Since the received signal over a nonlinear channel is a nonlinear function of the past values of the transmitted data pulses, it is not surprising that the linear equalizers do not work efficiently. We propose a new nonlinear equalizer that uses a new type of neural network called a Fuzzy CMAC which combines the advantages of both fuzzy logic and CMAC (Cerebellar Model Arithmetic Computer) networks. The learning speed is an order of magnitude faster than convention neural nets. Moreover, human expert knowledge in the form of linguistic rules can be easily incorporated into the scheme.
- Optimization of Phase-Locked Loops with Guaranteed Stability
by C.M. Kwan, H. Xu, C. Lin, and L. Haynes
- Abstract: Phase-locked loops (PLL) have found applications in many industrial applications such as communication and control systems. The key requirements are stability and loop performance in terms of signal-to-noise ratio and tracking errors. Here we present a two-step approach to PLL design. First, we present a Lyapunov approach to analyze the loop stability. The parameter range that can guarantee stability can be easily derived in the process. Second, we present a multi-objective optimization method that can search a set of values within the above range of parameters to achieve an optimal trade-off between loop bandwidth, transient and steady-state performance. Simulation results are contained to illustrate the performance of our procedure.
- Baseband Group Delay Equalization of IF Filters for Data Communications
by Thomas C. McDermott, N5EG
- Abstract: One source of phase (and thus group delay) variation is the IF filter in the receiver. This is either a mechanical filter or more commonly, a crystal filter. These IF filters typically have been optimized for best amplitude rejection of out-of-band signals vs. achievable passband flatness for a given number of filter poles. This typically leads to a Chebychev filter implementation which can have significant group delay variation. If the group delay variation vs. frequency is significant compared to the symbol rate (in baud) then the bit-error-rate of the received signal may be substantially degraded. Techniques to equalize the filer at IF are possible, but may prove difficult to implement and adjust, however they work well independent of the modulation type. On the other hand, equalization of the filer delay at baseband is possible, but is only exact for linear modulation types (PSK, QAM). FSK modulation (which is non-linear) cannot be exactly compensated at baseband, but if the deviationindex is low, then a reasonably good job of delay equalization at baseband can be accomplished. This article examines some amplitude, phase, and delay properties of first-order, second-order, and all-pass filters. In addition, examples of Chebychev and Butterworth IF filers are illustrated. Finally, a graphical representation of delay equalization at baseband is shown. Much of the information presented in this paper will appear shortly in Wireless Digital Communications: Design and Theory.
- Easy to Follow Packet
by James Nobis
- Abstract: This paper is a general introduction to packet radio. It explains how to setup your packet station and discusses how to use RoseSwitch, TexNet, and TheNet Nodes.
- Object-Oriented Modeling of a Satellite Tracking Software
by M. Normandeau and M. Barbeau, VE2BPM
- Winner of Best Technical/theory-oriented Student paper
- Abstract: This paper presents a case study of an object-oriented development of a satellite tracking software. It is designed following the Real-Time Object-Oriented Modeling (ROOM) methodology. The design resulting from the application of ROOM is implemented in C++ on the QNX platform. Concurrent actors are naturally mapped to parallel processes. ROOM yields a modular architecture which is clear, reusable, and maintainable. Use of QNX leads to a highly performant and reliable system. This work is important because it shows application of advanced software engineering principles in a field where most of the development is still based on structured (and non-structured) techniques.
- XNET: A Graphical Look at Packet Radio Networks
by Richard Parry, W9IF
- Abstract: This paper describes AX.25 packet networks from a graphical standpoint using XNET, a software program specifically designed for network analysis. Networks are complex entities most easily explained visually. Through the graphical displays, one can more easily gain an appreciation and understanding of a network. It also allows one to see problems and the general behavior of the network. XNET runs on UNIX/LINUX systems supporting the Tcl/Tk language.
- A 9600 Baud modem for the LPT port
by Wolf-Henning Rech, N1EOW, Don Rotolo, N2IRZ
The 9600 Baud FSK modulation according to G3RUH uses our limited bandwidth resources much more efficiently than the popular 1200 Baud AFSK. But one reason for the packet user not to switch to FSK is the higher price of the modem hardware -- usually a TNC2 clone with a large FSK modem board. In contrast, 1200 baud AFSK can be decoded with a very simple and cheap adapter to a PCs COM port containing not much more than a TCM3105, and a BayCom modem originally designed by Johannes DG3RBU. Packet decoding is done by software in the PC, and there is a wide variety of drivers. Even the power supply is derived from the COM port.
We present here a simple modem for 9600 Baud FSK which can be connected to a LPT port (provided its IRQ is installed). It is also powered from the port and does not need any alignment. Several drivers for DOS and Linux are available because of its compatibility to the BayCom PAR96 modem (and its PacComm clones). With DOS and the BayCom program it operates with any computer higher than a 10Mhz 286. It has been originally published in the proceedings of the 12th Internationally Packet Radio Conference Darmstadt, 1996.
- Amateur Radio Digital Voice Communications
by Paul Rinaldo, W4RI
The telecommunication industry has been busy developing digital voice transmission technologies. While amateurs have made progress in other areas, digital voice has not kept pace. Maybe its because of lack of suitable standards, the unavailability of hardware, satisfaction with existing SSB and FM voice systems or the lack of urgency.
Well, time's up. We need to apply the same energies and talents we did previously in developing single sideband, amateur television, small satellites, and packet radio.
A design engineer once told me, the longer you wait, the easier the job. Obviously, he meant that new devices are constantly becoming available, maybe even the specific application you have in mind. This is true in the case of digital voice coder-encoders (CODECs). Instead of developing coding algorithms and designing application-specific integrated circuits (ASICs), someone else may have handled these chores for you.
Appendix: Spectrum Efficient Digital Land Mobile SYstems for Dispatch Traffic . Working Paty 8A. Draft New Recommendation ITU-R M. [8A/XB]. (47 pages)
- WinAPRS: Windows Automatic Position Reporting System. A Windows version of APRS.
by Keith Sproul, WU2Z and Mark Sproul, KB2ICI
- Abstract: WinAPRS is a Windows version of the popular APRS, AUtomatic Position Reporting System. WinAPRS is fully compatible with APRS, the DOS version, and the MacAPRS, the Macintosh version. Due to the larger amounts of memory available in the Windows operating system, WinAPRS, just like MacAPRS has mahy additional features not available in the DOS version. This papers describes WinAPRS.
- Automatic Radio Direction Finding Using MacAPRS and WinAPRS
by Keith Sproul, WU2Z
Radio Direction Finding has been around for almost as long as radio itself. Doppler-based RDF systems have been around for quite awhile too. In the recent past, people have developed computer interfaces to Doppler-based RDF systems. APRS has the ability to display the RDF information on maps, giving the user a graphical way to view the RDF patterns.
Over the last few years, the call sign database available on CD-ROM from several companies have become more and more sophisticated. There are also databases of commercial frequencies and locations available.
Most of us involved in Amateur Radio have experienced situations where we need to track down the cause of an unwanted radio signal, i.e. stuck microphone, improperly tuned equipment, or even a jammer.
With all of the available technology, we should be able to develop a system that zeros in on a location and automatically shows us the possible transmitters in the area.
- Circus of the Stars
by Michelle Toon, KC5CGH
- Winner of Best Educational or Community-Oriented Application Student paper
- Abstract: A unique collaboration between diverse groups is proving that, in Waco, Texas, the sky's the limit. This project uses amateur radio to tie sites in the Central Texas area together during a mentoring session based on night-time astronomical observation.
- 13cm PSK Transceiver for 1.2Mbit/s Packet Radio
by Matjaz Vidmar, S53MV
- Abstract: This paper describes the design of a 13cm 1.2Mbit/s PSK transceiver for packet radio by Matjaz Vidmar, S53MV. Includes: schematics, layout, figures, and experimental results.
- 23cm PSK packet-radio RTX for 1.2Mbit/s user access
by Matjaz Vidmar, S53MV
- Abstract: This paper describes the design of a 23cm 1.2Mbit/s user access RTX by Matjaz Vidmar, S53MV. Includes: schematics, layout, figures, and experimental results.
- Packet and Internet
by James Wagner, PhD, KA7EHK
- Abstract: Debate is one of the interesting aspects of the packet BBS system. One of the recent debate issues is really quite important to all of us. It concerns the question of BBS mail forwarding by methods other than the ham RF network. Whichever side proves to be "right", (and it is possible that both may be right), the answers to this debate will have an impact on all packet users.
- Strategies for Improving Wide-Area Networks
by James Wagner, PhD, KA7EHK
- Abstract: Wide-area single-frequency networks still cover large areas of this country. A number of strategies have developed for improving such networks, but these strategies are very slow to be adopted. This paper discusses some of the reasons for the continued existence of these networks, some of the strategies and their likelihood of success.
- The Word Storage Relay
by Pat West, W7EA
- Abstract: This papers discusses the Word Storage Ralay developed for the BOMARC (Boeing and Michigan Aeronautial Research Center) radio control systems.
- On-Air Measurements of HF Data Throughput Results and Reflections
by Ken Wickwire, KB1JY
- Introduction: For the past year a team of colleagues and I have been collecting and analyzing data on the throughput and other characteristics of various ARQ protocols available to hams and commercial users for HF work. This activity was motivated by discussions (especially among hams) about the relative merits of the new HF digital modes, such as PacTOR, GTOR, CLOVER II, CLOVER-2000, and PacTOR II. Since the discussions often centered on throughput in various conditions, and we were already running several of the protocols, we decided to see for ourselves. This paper describes our assessment approach and measurement campaign, gives summary of our main conclusions, and lists some findings worth noting before protocol choices are made and protocol performance is compared. The paper treats the packet and TOR modes in detail. More extensive reports on CLOVER II, NOS TCP/IP and the ALE orderwire will appear elsewhere.
- On-air Measurements of MIL-STD-188-141A ALE Data Text Message Throughput over Short Links
by Ken Wickwire, KB1JY
- Introduction: For the past six months a colleague W1IMM and I have conducted automated measurements of throughput when ASCII text files are sent over short or "tactical" HF paths using the ALE Data Text Message (DTM) engineering orderwire (EOW). This is a preview of our results.
- The Technology Grows and Matures
by Bill Henry, K9GWT
- Abstract: The CLOVER waveform idea was first presented to radio amateurs by Ray Petit in the July, 1990 issue of QEX. This paper covers early CLOVER lessons, the use of CLOVE in marine applications, Voice bandwidth CLOVER, CLOVER in the future.
- Constructing a Worldwide HF Data Network
by Craig McCartney, WA8DRZ
- Abstract: The construction of a data communications system presents a wide range of challenges to the network designer, depending upon the needs of the user. Choosing High Frequency (HF) radio as the communications medium adds significant challenges of its own - challenges that are known to radio amateurs and shortwave listeners worldwide. This paper describes the design choices made by a commercial company, Globe Wireless, while setting up a Global Radio Network to serve the maritime industry. The technical choices were based, at least in part, on methods and practices first developed in the amateur radio community. Perhaps the explanations that follow will assist amateurs when faced with similar choices.