Papers may be downloaded in PDF format by clicking on the link below each abstract. If you prefer, you may purchase a CD-ROM with the entire proceedings on it for this year and several others.
This proceeding is available on CD-ROM
- Location:
- Orlando, Florida
- Coordinators:
- Steve Stroh, N8GNJ, Conference
Manager
- Geoff Dick, WA4IKQ, Local Host Liaison
- Geoff Dick, WA4IKQ, Local Host Liaison
- Hosted by:
- Lake Monroe Amateur Radio Society (LMARS)
- Orange County ARES/RACES
- Seminole County ARES/RACES
- Orlando Amateur Radio Club (OARC)
Read the conference story with audio and photos.
Abstracts:
19th ARRL and TAPR Digital Communications Conference
September 22-24, 2000
- EasyTrak, A PIC /Based Rotor/Radio Controller Interface
by Steve Bible N7HPR - Abstract:
EasyTrak is a rotor/radio controller interface based on
the Microchip PIC16F87x series. PICmicro microcontroller. The goal was to
design a rotor/radio interface that is compact, low-cost and easy to use. The
PIC microcontroller contains many of the peripherals needed to design a
rotor/radio controller interface: analog to digital converter (ADC), timers,
serial interface (USART), and individually programmable I/O pins. In addition,
the PIC contains FLASH ROM for easy programming and upgrades, RAM for system
variables, and EEPROM for storage of non-volatile configuration information.
With a small amount of interface circuitry around the PIC microcontroller, the
goals of the compact and low-cost were obtained. Ease of use was obtained by
designing EasyTrak to interface to the most popular azimuth/elevation rotors
and a serial RS-232 interface to communicate with virtually any computer.
EasyTrak is designed to easily interface to the Yaesu series of azimuth/elevation rotors, model numbers G5400B, G5600, and the newest G5500. These rotors have a computer interface built in with an 8-pin DIN connector on the back of the rotor controller to control left, right, down, up and provide rotor position via a proportional 0-5 VDC analog signal for azimuth and elevation. EasyTrak can be interface to other rotors, for example rotating HF antennas, but will require user modification of the rotor controller. Optional relays can be installed on EasyTrak to provide normally-open (NO) or normally-closed (NC) contacts for azimuth, elevation, and brake.
The computer interface is via a serial RS-232 connection. The rotor controller protocol is based on Chris Jackson's, G7UPN, EasyComm protocol. EasyComm is a simple ASCII character based protocol for controlling rotors and radios. The benefit was that a new protocol did not have to be created, it is easy for programmers to write for and interface to, and several programs already have EasyComm programmed in: WiSP, Nova, MacDoppler, MacAPRS and WinAPRS. The Mac and WinAPRS programs have the unique feature of tracking high and low altitude balloons in azimuth and elevation as well as other objects. Mac and WinAPRS can also point HF beams using the DX Cluster feature or point to a moving object in azimuth only.
- APRS Tiny Web Pages
by Bob Bruninga WB4APR - Abstract:
Although APRS has revolutionized packet radio, it is also
one step ahead of the next great leap in wireless technology which is handheld
wireless access to Web pages. Although cell phones and pagers are just
beginning to capitalize on this next wave of technology, APRS already has it!
Take a look at the screen of your Kenwood TH-D7 or TM-D700... What you see are
hundreds of Tiny Web Pages of information!
- New Millenium Morse
by Roy Ekberg W0LIQ and Martin Schroedel K9LTL - Abstract:
This covers aftereffects of 5 WPM Morse on Computer
Assisted Communication (CAC) system proposed in the 17th ARRL and TAPR
Proceedings. A prototype in ARRL's Library is indexed C-135-1. R & D on
this began in 1989.
- Correlation for Direct Sequence Spread Spectrum
by Panagiotis Gavalas - Abstract:
Spread Spectrum systems have become very 'trendy toys' in
the areas of radio engineers and enthusiasts. Not only they provide privacy to
the user, as an extend the ingenious channel encoding techniques involved make
such systems very challenging for communications engineers and radio
enthusiasts. Direct Sequence systems as the most preferred as they are the
easiest to play with. Sadly, among the articles and textbooks written on
Spread Spectrum there are not many examples provided to the amateur radio
enthusiasts. The concepts behind SS applications tend to be rather difficult
to grasp and thus put the radio enthusiast in a very difficult position in
terms of understanding and designing of such a system. As an extend, some
already available examples demand the use of complicated circuitry and
expensive ICs. Thus, amateur radio enthusiasts are put in the risk of loosing
valuable time and money in case of failure or possible damage of expensive
components due to the idiosyncrasies of such ICs. Thus an easy and cheap
solution is necessary. This article is written in order to explain the concept
of correlation in the simplest possible way to the amateur radio enthusiast
and thus provide a simple solution concerning the heart of the system, i.e.
the circuit that performs the de-spreading. It could be used as a reference or
a manual and the circuit described has the potential to be adjusted to any
Direct Sequence SS system used for digital data transmission.
- An MSK Mode for HF DX
by Murray Greenman, ZL1BPU and Nino Porcino, IZ8BLY - Abstract:
Development of a very robust and sensitive modem for
Amateur DX use. A description of the main problems involved in receiving
digital modes on HF, and ways to counter them; a brief history of MFSK, and a
description of MFSK technology. A description of the design process of a new
MFSK mode for amateurs, its performance, and the software used to demonstrate
it.
- A Zero-IF Digitized Despreading Scheme Without PN Code Synchronization
Recovery
by a href="mailto:hguo@mcn.xidian.edu.cn">Hong Guo, Feng Guo and Tao Duan - Abstract:
Zero-IF is a important method to digitize the despreading.
In this paper, a fast zero-IF digital dispreading scheme with PN code
synchronization recovery is given, which is based on performance analysis to
chip rate sampling in AD converter.
- PIC-et Radio II: How to Receive AX.25 UI Frames Using Inexpensive PIC
Microcontrollers
by John A. Hansen, W2FS - Abstract:
This paper provides step by step documentation of how to
decode AX.25 UI frames using inexpensive PIC microcontrollers. It is designed
primarily for those who wish to receive packet radio UI beacons from point to
multipoint communications. The article assumes some knowledge of programming
concepts and PIC microcontrollers.
- Winlink 2000 ...A Global Ham Message Transfer and Deliver Network
by Hans Kessler, N8PGR, and Vic Poor W5SMM, Rick Muething KN6KZB, and Steve Waterman K4CJX - Abstract:
Early digital modes broke from the traditional
"live" interactive QSO and fathered the now familiar store and
forward message systems we now take for granted in our BBSs and e-mail. The
increased demand for mobility in Ham radio has evolved into the need for a
reliable, rapid, global message transfer and delivery network that spans both
the Ham radio and Internet domains. This paper describes the implementation of
the next generation Ham message and information network that allows mobile
users global connectivity to other amateurs, Internet mail users and WEB based
information while remaining free of the constraints of the "home"
BBS. Winlink 2000 is now a fully operational global network serving thousands
of mobile ham users and providing reliable connectivity for both text, and
binary data.
- Frequency Offset Acquisition and Tracking Algorithms, Part 1
by Mohamed K. Nezami - Abstract:
Wireless receivers process signals that bear information
as well as disturbances caused by the transmitter/receiver circuits and
channel impairments such as fading, interference, and additive white gaussian
noise (AWGN). Usually, the receiver knows only some statistical properties of
the signal and disturbances. From these statistical properties and using a
finite observation of the received signal, the receiver is able to estimate
the transmitted data symbols.
- Frequency Offset Acquisition and Tracking Algorithms, Part 2
by Mohamed K. Nezami - Abstract:
In part I, several algorithms were developed for carrier
frequency offset acquisition. The algorithms estimate the offset frequency
independent of the carrier phase errors or symbol timing. Phase errors are
estimated and corrected, after frequency estimation and correction as shown in
figure 1 of part 1. In part II, phase estimation algorithms using open loops
and close loops techniques are presented, a particular application example
will be the use of both techniques for acquiring and tracking short TDMA burst
satellites. Finally, practical methods for implementing these algorithms using
commercial DSP chips are introduced.
- QuakeAPRS
by Richard Parry, W9IF - Abstract:
QuakeAPRS provides the APRS network with near real-time
earthquake information. It is a perl script run as a cron job on a Linux
machine. When the script is executed on the hour and half hour, it connects to
the USGS to collect earthquake data. It then converts the information to the
standard APRS packet format and sends it via the Internet to APRServe. This
allows APRS clients to easily display and track earthquakes. QuakeAPRS has
been running 24/7 for nearly a year. This paper describes QuakeAPRS, the
earthquake object format, and lessons learned from the development of this
applications.
- Soundmodem on Modern Operating Systems
by Thomas Sailer HB9JNX / AE4WA - Abstract:
Five years ago I presented drivers for using standard PC's
with soundcards as packet radio modems [13]. The mainstream CPUs of that era
were not quite powerful enough for complex signal processing, so the design at
that time had to trade robustness for computational simplicity. Furthermore,
operating system preferences have changed since. It is therefore time to
rethink the design. In this article, an up to date implementation of an
amateur soundcard packet radio driver is presented that features a common
source base supporting all major operating systems, and the most common
modulation formats.
- External Common Gateway Interface (CGI) Access to FindU
by Thomas M. Schaefer, NY4I - Abstract:
This paper provides programmer documentation on external
access to the FindU database. The Common Gateway Interface (CGI) is used as an
example of methods for a script or program written on a web server to access
that database.
- Server Applications within APRS Internet Server Environment
by Thomas M. Schaefer, NY4I - Abstract:
This paper discusses programmatic opportunities to access
the Internet servers offering APRS data. Particular attention is made to the
APRServe system in Miami. Using this system, it is possible for a programmer
to create applications that utilize APRS data to create new dynamic and useful
applications.
- Intelligent Filtering of the APRS Internet Gateway Data Streams
by Darryl Smith, VK2TDS - Abstract:
APRS is a fast growing mode throughout the Amateur Radio
world, thanks to its combination of computers, radio, packet and the Internet.
Such popularity has increased the amount of data on the APRS network to a
point where many users, especially those outside North America, are
overwhelmed by the volume, or in an attempt to reduce the traffic volume do
not enjoy the full benefits if Internet Connected APRS. This paper describes
work by the Author into filtering the data stream intelligently to create
manageable local networks.
- APRS and the TAPR EasyTrak Az/El Rotor Control System
by Keith Sproul, WU2Z - Abstract:
APRS, Automatic Position Reporting System, has been used
to track many things. It has been used with DX Cluster for showing where the
DX stations are located. It has been used to track cars, boats, bicycles,
motorcycles, weather balloons, and hot air balloons. It has even been flown on
the Energizer Bunny Hot Air Balloon many times. When tracking balloons,
especially the high-altitude weather balloons, normal antennas work fine for
the Packet/APRS/GPS signals. But when you are trying to receive ATV (Amateur
Television) signals from the balloon, you need much better antennas. Usually
you need to have a high-gain antenna of some type pointed directly at the
balloon. APRS already knows where you are, and it knows where the other
stations are. From this information, it is easy to calculate the angle(s)
needed to point a directional antenna at the other station, when needed.
- APRS and Kenwood TM-D700 Voice Messaging
by Keith Sproul, WU2Z and Mark Sproul, KB2ICI - Abstract:
MacAPRS has had speech capabilities for messaging for many
years. WinAPRS has the ability to use wave files for some functions. APRS Plus
has wave file capabilities too. To put voice features on a normal computer is
easy. Last year we wrote a paper about wanting a message 'speaking"
device using some kind of text to speech system if we could find one. These do
exist, but they are not cheap, and also are not very small. Last year, Kenwood
introduced the TM-D700 which had the ability to do some of what we wanted,
built right into the radio. This 'speech' feature has proved to be very
useful. This paper is about the voice messaging feature of the Kenwood
TM-D700.
- Internet Wide Callsign Database using LDAP
by Mark Sproul, KB2ICI - Abstract:
LDAP, Lightweight Directory Access Protocol, is an
internet protocol for storing directories. It has many uses but the most
common use is for keeping track of large lists of personnel. Many attributes
can be associated with each entry such as name, email address and callsign.
LDAP is a standard and is easy to incorporate support for it in any
application. There are libraries for use with C/C++ Java, PHP and many other
languages as well as all platforms. LDAP is also supported already in many
end-user applications such as Netscape.
- <APRSdec>--The G3NRW APRS Packet Decoder
by Ian Wade, G3NRW - Abstract:
This paper describes the principal features of the <APRSdec>
program. The program fully decodes raw APRS packets, producing reports in
plain English. It has proved to be an extremely useful APRS diagnostic and
learning tool. <APRSdec> is written in Perl, and runs under native DOS,
Windows, Unix, and Linux. It is available from
http://www.tapr.org/~g3nrw.
- Throughput and Probability of Correct Message Transfer of the Pactor-II
System Measured on Near-Vertical-Incidence-Skywave (NVIS) Paths
by Ken Wickwire KB1JY, Mike Bernock KB1PZ, and Dave Willard W1EO - Abstract:
This paper is another in our series treating on-air
measurement of throughput in characters per second (cps) for various HF
data-transmission protocols of interest to amateurs (see the references to our
other reports at the end of the paper). Here we describe an extensive set of
measurements of throughput for compressed and uncompressed text files sent
over near-vertical incidence-skywave (NVIS) paths with the Pactor-II data
transfer protocol. The implementation we used was the one in the Special
Communications System (SCS) modem.
- Automatic Voice Relay System - (AVRS)
by Bob Bruninga, WB4APR - Abstract:
AVRS is a "VOICE" addition to APRS. Just like
APRS now provides mobile-to-mobile worldwide MESSAGE capability via the
Internet APRServe system, there is no reason why we cannot add voice to this
same type infrastructure for mobile-to-mobile voice. And AVRS is not limited
to one channel It can be expanded to as many channels as the locals want (i.e.,
it can handle explosive growth)... Internet connection of local Repeaters is
not new. Iphone links have been going on for several years, but with the lack
of any common user commandable access-on-demand and the completion for on-air
time with conventional use of the repeaters, it remains as just a novelty.
But, by tying this capability into the command structure and worldwide text
messaging capability of APRS the mobile user would then have total control and
could "dial up" a link anywhere on the planet. Remember, he can
already communicate by text message to confirm the other person is on the air.
AVRS then lets him open a voice link to that same area.
- Intelligent Digipeating using DIGI_NED on Obsolete PCs
by Henk de Groot, PE1DNN - Abstract:
In Europe the roll-out of APRS is well under way right
now. However, we do not have a stable APRS infrastructure. This paper
describes how we use old and obsolete PCs, together with packet hardware
commonly used in western Europe, to augment the APRS infrastructure.
- Channel Capacity Simulation of Peer-to-Peer Spread Spectrum Satellite
Transponders
by Matthew Ettus, N2MJI - Abstract:
A spread spectrum transponder for the International Space
Station has been proposed, the goal of which is to provide medium to high bit
rate digital communications to radio amateurs. In order to help predict the
capabilities of such a system, as well as aid in its design, a simulation of
system bit error rates has been performed. The simulation is performed at the
channel symbol ("chip") level, using a freely available
communications system simulator package. The results of these simulations show
that over a hundred users may participate in digital voice communications at
any time using the transponder.
