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Publications:

ARRL and TAPR 22nd DCC 2003

General notes:

Copies of the papers presented at, or published for DCC are available in various ways. A paper printed in the proceedings will be available for purchase in most cases in hard copy as the DCC proceedings. It will in most cases also be available as an individual paper in PDF format as a free download via a link below the abstract (where available) It may also be available on CD-ROM. A paper printed in the proceedings may not have been presented at the conference. Also a presentation at DCC may not be in the printed proceedings. In those cases it may be available on DVD, CD-ROM or as a MP3 download. Links to what is available will be on the page specific to the particular year's DCC.

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Location:
Hartford, CT


Read the conference story with audio and photos.


Abstracts:
22nd ARRL and TAPR Digital Communications Conference
September 19-21, 2003

Solving Noise Problems in Modern Radio Systems
by Bryan Ackerly, VK3YNG
Abstract: In recent times there has been a substantial increase in the use of digital technology in radio systems. This sort of technology has been slow to catch on in amateur circles due partially to the fear and misunderstanding of the noise problems associated with mixing RF systems with digital technology. Many amateurs to date have avoided the mixture ofthese technologies. In contrast survival in the commercial world requires it to battle with these issues on a regular basis.

This paper draws on knowledge gained on both commercial and amateur projects that successfully combine these technologies and indicates methods that can be used to produce working designs.

Proceeding Paper

PMap...New Windows Based APRS Client Software
by John Blowsky, KB2SCS
Abstract: Why was PMmap created? The software was created to fill the perceived need for APRS client software that not only follows the APRS spec. to the letter but also does APRS like APRSdos. The software was developed on a 133 MHz PC with 64 meg ofRam. PMmap has run also run on a 120 MHz Laptop with 16 Meg ofRam. The running on lesser computers fills the need for "Come as you are" emergency communications. Yes the software runs slow on the Laptop but not so slow as to be unacceptable.

Proceeding Paper

AMSAT Oscar-Echo, SDR-1000, and Higher Speed FSK
by Frank Brickle, AB2KT and Bob McGwier, N4HY
Abstract: If all goes well, in May 2004 AMSAT-NA will launch its newest satellite on the Dnepr LV (a converted SS-18) from a Russian launch site. The satellite has the ability to support several digital modes. They will be difficult to support using offthe shelf conventional transceivers. Recently, a realistic candidate has emerged in the form of an affordable and easily usable software defined radio (SDR). In this paper we will describe the digital capabilities of AMSAT-ECHO, the new satellite, and how the software defined radio can be the ideal terrestrial station for exploiting those modes. We will discuss the changes and upgrades to the SDR, to be provided by the manufacturer, that will be necessary for this added functionality.

Proceeding Paper

Overview of Dynamic Forward Routing
by Edwin Brownrigg
Abstract: Dynamic Forward Routing (DFR) is a software implementation of two U.S. patents (USPTO 6,044,062, March 28,2000; 6,249.516, June 19,2001) that express the invention of a software defined Mesh Protocol. DFR, used in combination with Internet Protocol (IP), enables a metropolitan area network to configure itself dynamically. In a multi-radio wireless network, there are no pre-determined fixed paths. All routes are indeterminate. Worse, there can be many indeterminate paths, which if taken without intelligence can congest the network to the point of guaranteed failure.

Proceeding Paper

Exploiting the Dynamic Flexibility of Software Radio in FM Broadcast Receivers
by Declan Flood, Linda Doyle, Philip Mackenzie, Keith Nolan, and Donal O'Mahony
Abstract: This paper demonstrates how the flexibility of software radio may be exploited to optimise radio communications systems. It describes our implementation of a software radio RDS (Radio Data System) receiver. Most FM stations transmit a RDS signal in addition to their audio output. RDS provides information about the current FM broadcast such as the program name etc. RDS is very similar to the North American RBDS (Radio Broadcast Data System). Our implementation of the receiver uses high level RDS information to adapt itself. The objective is to improve the receiver's functionality for the user and to reduce the computational load.

Proceeding Paper

TNC-X: An Expandable Microcontroller-Based Terminal Node Controller
by John Hansen, W2FS
Abstract: TNC-X is a new Terminal Node Controller design based on the Chepponis/Karn KISS protocol.] It is implemented using a Microchip PIC 16F628 microcontroller, a CML MX614 Bell 202 modem chip, an 8K Ramtron FRAM, a Maxim MAX232A level converter chip, and a dual op-amp which provides active audio filtering for the modem. From the beginning, this TNC was designed to be small, have low power consumption, and, most importantly, be expandable. Expandability stems from two sources. First there is an on board socket for a DLP-USB232M USB module which provides the TNC with a USB port. Drivers that are shipped with the module make it appear to the host PC as a standard serial port. Thus PC software that expects to see a serial port on the computer will interpret the TNC-X as being connected to such a port, even when the PC has no serial ports, or they are all used by other applications. In addition, when the USB option is used, the TNC can be powered from the USB port of the computer; no other power supply is needed.

Proceeding Paper

Real-Time Speech with AX.25 - An Evaluation of the Possibilities and Restrictions
by Nicolai Heilemann, DL9TS
Abstract: A study about the possibilities of real-time speech transmission using amateur packet radio is presented. In this study it is shown, that a common 9600 Bitjs-channel has the theoretical possibility of transmitting speech data with only short delays. The restrictions of the AX.25 protocol for real-time transmission are discussed, showing that an appropriate setting of the transmission parameters still allows real-time transmission. A hybrid emulation system using traces from a real wireless channel as well as coded speech gives an estimation of the expected speech quality and an implementation of a real-time transmission tool allows first experiments. Preliminary results of these experiments show the possibility to use AX.25 for real-time speech transmission even if the resulting speech quality is not yet satisfying. However the tolerance of listeners towards distortions has been much higher than expected and there are possibilities to improve the system with respect to the user perceived speech quality.

Proceeding Paper

GPS Solutions for Tracking Applications in Steel Industry
by R.K. Jha, K.K. Mallik, S. Jha, S.M. Mohanty, M.S. Sharma, and T Ravindra
Abstract: GPS (Global Positioning System) is a satellite based radio navigation system. The unique feature of this system is that it allows users to determine their three dimensional position, velocity and time anywhere in the world: be it land, sea or air. Like many other applications initially developed for military purpose, it is now being increasingly used for civilian purposes. GPS based vehicle tracking system can have various interesting and extremely useful applications in steel industry involving raw material handling, hot metal and steel ladle movement, dispatch of finished products etc.

Proceeding Paper

The DSPx: An Experimenter's Module for Digital Signal Processings
by Lyle Johnson, KK7P
Abstract: There has been interest in applying digital signal processing (DSP) techniques to Amateur radio for more than a decade.

In the early 90's, AMSAT and TAPR teamed to produce a standalone external unit, the DSP-93. This kit provided advanced filtering and modems. Its cost was high, and a later effort was made to incorporate the Motorola DSP56002 Evaluation Module (EVM) into a similar enclosure. This was lower in cost and fairly popular, but Motorola soon discontinued the EVM.

In 1999, Bob Larkin, W7PUA published his DSP-lO Software Defined Radio articles in QST. This was built around an Analog Devices development board, which sold for only $89. This same board was the basis for all of the DSP experiments in the latest ARRL publication, Experimental Methods in Radio Frequency Design. Alas! Analog Devices increased the price of the evaluation board from $89 to $245, and has all but discontinued it in favor of more current technology. During the late 90's, soundcards began to appear in personal computers. Today, it is difficult to find a PC without a soundcard. And modem PC processors include DSP instructions which execute at incredibly fast rates. This has resulted in an explosion of available software to use the soundcard in conjunction with a radio to perfonn DSP tasks. Witness the explosion in popularity of "soundcard modes" such as PSK31.

What's an experimenter to do?

Proceeding Paper

SDR and VLF Time Signals
by Poul-Henning Kamp
Abstract: VLF signals have been used to transmit precise time and frequency signals since roughly the second world war and even in these GPS days, DCF77 and WWVB signals are probably still responsible for getting more people out of bed in time than any other time and frequency distribution method.

This paper outlines some experiments on receiving a decoding these signals using a software defined radio, and the results obtained. For illustrations and data please see the URL in the paper.

Proceeding Paper

ERMTP: An Eventually-Reliable Message Transmission Protocol for a Low-Bandwith HF Environment
by Huilong Huang, KD7YCO and Stephen Pink, KF1Y
Abstract: Why Low-Bandwidth Reliability?

PSK31 has developed into one of the most popular digital modes of the last few years with its relatively easy to use software combined with a very efficient use of amateur spectrum. Another reason for PSK31's popularity is that all an amateur needs to have is a general purpose computer running the PSK31 software; i.e., no special hardware is required. The limiting factor, however, in PSK31 communication is that this mode supports only unreliable communication, making keyboard-to-keyboard chat about the only feasible application. Other services besides chat such as file transfer, email, etc. need support from the underlying channel that corrects for all (or most) errors in the communication. It seems impossible to support reliable communication with the kind of coded, lowbandwidth, simplex channel provided in PSK31. For such reliable communication support, one has had to resort to modes such as Pactor II, which uses many times more bandwidth and needs specialized hardware to provide a reliable and reasonably efficient channel of communication.

The purpose of this paper is to present a new protocol, the Eventually-Reliable Message Transport Protocol (ERMTP), that can provide reliable communications over low-bandwidth noisy radio channels such as HF. We envision this protocol to support such applications as email and file transfer and their variations such as world wide web communication. ERMTP uses a half-duplex channel that delivers packets or cells of data to the application that has been checked for accuracy by the sender and receiver. Our current implementation of ERMTP is based on PSKCore and, with some modification, can be used with current PSK31 user applications. Our intention is to create a reliable message service for the support of traditional data applications, yet retain the low-bandwidth quality of PSK31 as well as the reliance on PC sound-card-only hardware technology.

Proceeding Paper

Off the Shelf Digital Radio
by Victor Kean, K1LT
Abstract: Need for Complex Antennas

I have been an avid 160-meter contester for a number of years. The 160-meter band interests me because the long wavelength makes antenna design a challenge not easily solved by the mere application of money. Furthermore, receiving antenna design becomes the focal point of station performance because of the nature of 160-meter propagation.

The standard approach to 160-meter receive antenna systems uses the Beverage Wave antenna. One strings a long wire, low to the ground (about 10 feet) for several hundred feet in the direction of the desired signal. A contest station typically uses 8 of these antennas to cover 8 compass points. The clever use of transformers allows one to use a parallel pair of wires to cover two opposite directions. A high performance-receiving array consists of 4 pairs of wires, about 800 feet long each laid out like a + and an X superimposed. Thus, the high-end station requires about 15 acres of land.

An array of verticals requires considerably less real estate for comparable directivity.

Proceeding Paper

The Future of ARQ in Congested HF Bands
by Peter Martinez, G3PLX
Abstract: It is almost exactly 25 years to the day since the writer conducted the first experiments in the use of Automatic Request (ARQ) techniques, introducing for the first time the concept of error-free delivery of messages over the error-prone HF amateur bands, following this with the first experiments with automated store-and-forward techniques using ARQ links. This paper looks at the way in which ARQ techniques have been used within amateur radio since that time and attempts to extrapolate into the future. The conclusions reached are that current ARQ techniques have major flaws within the context of today's amateur radio community, and will have to undergo changes if the demand for error-free message-handling is to continue as part of amateur radio into the next 25 years.

Proceeding Paper

Telpac and Paclink - Streamlined AX.25 Packet Server and Client for a Full Service Ham Radio Messaging Network
by Rick Muethng, KN6KB and Vic Poor, W5SMM
Abstract: Ham radio's love affair with surplus hardware, budget software and a healthy volunteer spirit has served us well by keeping our hobby affordable while fostering many significant innovations. But the reality of high quality modem software is that it takes real programming skills and significant development time to build a worthwhile and reliable program. On-going enhancements and support also pose tough challenges when hams have come to expect free cradle-to-grave program maintenance. To manage development and maintenance efforts, a new approach had to be found for writing next generation packet servers and clients. These programs must be easy for sysops and users to setup, provide intuitive familiar user interfaces (e.g. Outlook, Netscape, Eudora) and reliably support both new and legacy BBS message systems and TNCs. This paper describes two examples of modem amateur packet programs along with implementation approaches that minimized the development effort and provided solid foundations for future contributions and easy maintenance.

Proceeding Paper

Direction Finding Abducted Children: Proposal for a New Amateur Radio Emergency Service
by Brian Neill, VA3BPN
Abstract: This paper is a proposal for a system that would enable amateur radio operators to pinpoint the location of an abducted child. Where possible the system uses equipment and protocol that is pervasive throughout the amateur radio community such as 2-m equipment, digital communications, direction finding equipment, APRS and ham emergency preparedness.

This system does require that the abducted child be carrying a special device. While this paper does not provide specifications for the actual device, a set of functional requirements are proposed in the hope that some qualified amateur will attempt to prototype and build a child location device (CLO).

Parent's and children's privacy are given due consideration throughout this paper. A number of security controls and mechanisms are included to ensure that police are the only party that is able to activate a child's device; and they must obtain key information from the parent before they are able to activate. The security oontrols aim to reduce the possibility of abuse, protecting the system and ultimately the child carrying a device (CLO).

Finally, the appendix suggests an operations framework to be used in a DF enabled search for an abducted child. This framework example is provided, as a means to describe how the ham community can respond to this class of emergency, should police ask their local amateur radio club for assistance.

Proceeding Paper

WAPaprs: APRS on a Cell Phone
by Richard Parry, W9IF
Abstract: WAPaprs is an application to display APRS information on a cell phone that supports the Wireless Application Protocol (WAP). It was written to provide useful APRS data within the size, memory, color, and bandwidth limitations of a wireless handheld device. The paper includes a description ofall menu options and example displays.

Proceeding Paper

DSP Programming Using DirectSound and MFC/VC++
by Frank Perkins, WB5IPM
Abstract: This paper discusses DSP programming using Microsoft DirectSound and MFCNC++. Topics covered include an overview of Microsoft Windows programming, the MFCNC++ framework, DirectSound, AX.25 demodulation and packet decoding, and simple TCP/IP Winsock communications. A packet monitoring program is used as an example. The link to the VC++ folder for this program can be found at www.tapr.org in the "Conferences" section.

Proceeding Paper

A Digital PSK31 Meter
by George Rothbart, KF6VSG
Abstract: Building a digital field strength meter for your PSK31 station. See more details at www.ssiserver.com/info/pskmeter

Proceeding Paper

HSMM - High Speed Multi-Media
by Neil Sablatzky, K8IT and Mark Williams, AB8LN
Abstract: HSMM -High Speed Multi-Media is focused on using IEEE 802.11b Standard and adapting it to Part 97 Operation on 2.4 GHz.

Proceeding Paper

Southern California Coastal Propagation Phenomenon
by Ed Sack, W3NRG
Abstract: During the Summer of2001, W3NRG set up a PSK1 BEACONet station1 on 28.131 MHz at his QTH in Coronado, California. Almost immediately, the station began to record the BEACONet signals of KF6XA whose Maidenhead locator code placed that station in Temecula, California. What made this reception interesting was that the distance between the two stations, 63 miles, is not characteristic of 10 meter ground wave propagation and there are at least three "mountains" in the path that obscure the simple line of sight.

The BEACONet PSK31 signal protocol includes a preamble of approximately 30 characters followed by a "payload" consisting of station call letters, number of times per hour the beacon is being transmitted, a station configuration code, the Maidenhead locator and a cyclical redundancy check signature (CRC.) Stations are or have been active in various parts of the United States and in Europe and Australia. The recommended transmission timing is between six and twelve times per hour. Software is available to record the reception of signals which pass the cyclical redundancy test and, in certain cases, even send reports over the internet automatically at menu selectable times.

Early on in the KF6XA to W3NRG data collection process we recognized a definite time dependency on the number of confirmed reports received by W3NRG. We published our early data in a QST article in June 2002 A profile of the terrain between the two stations is shown in that article. The reviewers of the article provided various explanations for the propagation that was being observed.

Proceeding Paper

Speech Synthesis Added to PSK31
by Ed Sack, W3NRG
Abstract: Radio Amateurs are well known for their keen interest in combining several technologies to provide new features for the hobby. One such combination is the use of computer speech synthesis to monitor PSK31 traffic. Thanks to the availability of an inexpensive speech synthesis program and freeware written by amateur N7YG it is now possible to listen to the text of a PSK31 stream rather than watching the text develop on the computer screen.

Proceeding Paper

Vocoder Redux: The AMBE-2020
by Dennis Silage, K3DS
Abstract: A Digital Voice Systems AMBE-2020 voice coder (vocoder) has been implemented as a functional replacement for the obsolete AMBE-IOOO. The effort, in part, was a capstone senior design project in Electrical and Computer Engineering at Temple University, which fosters advanced technical topics in undergraduate education using amateur radio. The implementation is open-source and complies with the data communication protocol ofthe original G4GUO AMBE-IOOO vocoder design. This AMBE-2020 vocoder is offered as a reasonable standard for amateur radio digital voice experimentation. Further documentation for the AMBE-2020 vocoder is available at www.temple.edu/k3tu.

Proceeding Paper

Legal Rules and Regulations in the Amateur Radio Computer Networks
by Miroslav "Misko" Skoric, YT7MPB
Abstract: This paper analyzes some elements in domestic and international regulatory principles that govern the use of the amateur radio service, as an embryo of the official educational, professional and scientific activities in the ICT areas. After the global and local situation being carefully analyzed, the paper suggests some rules and regulation improvements, according to the actual state of the modern wireless and computing technologies.

Proceeding Paper

APRS IP Moblie in a Non-Dynamic Wireless Environment or 802.11 APRS
by Darryl Smith, VK2TDS
Abstract: The APRS Internet Service is a wonderful concept for a highly distributed GIS system for connecting hardwired users to the worldwide collection of APRS gateways. However, the world is moving away from the idea of hardwired connections, and moving towards the situation where users are wishing to access the data of the iGate system whilst mobile.

While services such as FINDU.COM have the capability to send data to mobile devices such as laptops, PDA's and cell phones, this transmission of data is not necessarily bandwidth efficient -particularly when the maps are available already on the mobile device. Once colleague received a bill for about US$300 for his PDA for the month, with the majority from when he left FindU.COM running one night.

Whilst many of these devices allow a TCP/IP connection from the mobile device direct to the APRS Internet System (APRS-IS), the user is left with intermittent connections to the server -connections that are re-made when each new base station is encountered.

Proceeding Paper

Bazaar Ham Publicity: Applying the Bazaar Approach to Ham Radio
by Darryl Smith, VK2TDS
Abstract: Amateur Radio is not a hobby that has a single central controlling body, like the Catholic Church. Yet many people think ofthe hobby as if it did have a single body with the will and resources to publicize the hobby. This paper describes some new ways to think of the hobby, and presents some ideas to publicize it.

This is NOT a technical paper. It is intended to provide ideas on how other technical concepts can be marketed to the world.

Proceeding Paper

SDR Update
by Gerald Youngblood, AD5OG
Abstract: SDR-1000 Overview on the PC Based, Software Defined Radio with Open Software - GNU Public License, including the full specifications.

Proceeding Paper

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