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.
The price for the TAPR and ARRL 27th Digital Communications Conference 2008 Proceedings is:
$ 20 US +applicable shipping/handling.
27th ARRL and TAPR Digital Communications Conference September 26-28, 2008
- Chicago, IL
- Steve Bible, N7HPR,
- Hosted by:
- Mark Thompson, WB9QZB
- Kermit Carlson, W9XA
27th ARRL and TAPR Digital Communications Conference
September 26-28, 2008
- EcomScs and GateWayScs AX25 Packet Radio E-Mail
by John Blowsky KB2SCS
EcomScs and GateWayScs are two stand alone programs that I have created.
EcomScs is a Packet Radio E-Mail Client. Everything that you can do with your internet E-Mail client
you can do with EcomScs.
GateWayScs is a Packet Radio Internet E-Mail gateway. GateWayScs makes it possible for EcomScs to
send and receive Internet E-Mails. GateWayScs and EcomScs combined replaces my Both Way Radio Internet Email (BWRIE)
- A Brief Introduction to Delay Tolerant Networking
by Frank Brickle AB2KT
Delay Tolerant Networking is the art and science of moving bits around in bad situations, such
as between distant endpoints in deep space, or among unknown mobile users at uncertain positions.
We give a brief introduction to the technology that has been developed to provide network
connectivity in such situations.
- Frequency and Other New Initiatives in APRS since 2004
by Bob Bruninga WB4APR - TAPR/ARRL/AMSAT/USNA
Too many hams seem to have completely misunderstood APRS and think of APRS as just a
vehicle tracking system that transmits GPS coordinates. When in fact, APRS is exactly the opposite.
APRS is a receive and display system for the distribution and display of relevant immediate information
of use to the mobile operator and others in VHF range. Now that we have another major manufacturer
implementing APRS, it is time to get public perceptions back on track!
My response to those people who think of APRS as a tracking system is that the tracking-only
application is a relatively dead-end way of thinking about ham radio, and no wonder they are not
interested, because in most cases, no one really cares where they are. But flip it around, focus on the
receipt and display of local ham radio information and APRS represents the epitome of ham radio. It is
receiving signals and information pertaining to every aspect of Ham radio in the immediate VHF
surrounding area that is the joy of APRS. A single national calling channel and information resource to
everything happening in the local area.
- Avoid Infrastructure by Centralized Polling of Emcomm Email
by Andre Hansen K6AH - Amateur Radio Emergency Service, San Diego Section
The San Diego ARES Emergency Medical Services (EMS) sub-group utilizes the Winlink 2000
system for medical message handling. The Winlink 2000 system has a dependency on
Internet infrastructure which may not exist in a regional disaster.
Secondly, message density has increased to the point where trauma-center teams often have
to wait for the channel. Winklink 2000 could address this by adding channels and RMS nodes,
but not without a further dependence on infrastructure.
This paper describes a proof-of-concept test on an old idea: central polling of mail clients as a
means of maximizing the traffic on the channel.
- Digital speech within 100 Hz bandwidth
by Mike Lebo N6IEF
To modify and write code needed to convert analog voice into narrow band digital modulation. The bandwidth of voice is about 2400 Hz. When speech could be reduced to 100 Hz, the gain would be
13.8 dB (24X). Processing gain by a computer is cost free. This project receives weak signals 10 dB
(10X) below SSB (Single Side Band) noise floor of the radio.
- D-STAR® Uncovered
by Peter Loveall AE5PL
D-STAR® is a digital streaming over-the-air protocol developed by
Japan Amateur Radio League,
Inc. (JARL) which supports Ethernet at 128 kbps (DD) and digital voice at 4800 bps (DV). DV uses
3600 bps for voice (2400 AMBE encoding, 1200 bps FEC) and 1200 bps for synchronization and
multiuse (approximately 900 bps is available for general use). DD provides an encapsulated Ethernet
bridge for connecting two or more Ethernet clients over RF. We will explore this bit streaming protocol,
its primary components, and current implementations. This paper explores the protocol from a
technical, not subjective, viewpoint.
- A Protocol for Multicast Weather Data Distribution Over AX.25
by Nick Luther, K9NL
A protocol is described for use on top of AX.25 in order to form multicast, push-architecture, regulatory
compliant, radio weather data links. This protocol is especially suited to disseminating NEXRAD
weather surveillance radar data over 1200 baud AFSK VHF radio links. Further, a larger scale system
for distributing weather data using various means, among them radio links using this protocol, is
discussed along with the current status of its implementation. Using the defined protocol over a radio
link along with other system components, it is possible to ingest NEXRAD data from fast, operational
data sources and to relay that data to severe weather spotter resources in a timely fashion, even when
those resources have no access to the Internet or other data network infrastructure.
- WINMOR…A Sound Card ARQ Mode for Winlink HF Digital Messaging
by Rick Muething KN6KB AAA9WK - Winlink Development Team
The improving computational performance of PCs and the near real-time response of PC operating
systems now make it feasible to implement reasonable performance HF ARQ messaging protocols
suitable for digital messaging. While Pactor (I, II, III) currently dominate and generally represent the
best available performance, PC sound cards with appropriate DSP software can now begin to approach
Pactor performance at lower cost than dedicated hardware HF modems. This paper covers the on-going
development of an optimized sound card mode WINMOR, compatible with the popular Winlink 2000
message system1,2,3. This effort leverages a prior feasibility project by the author in the evaluation of
SCAMP 4, an adaptation of RDFT for digital messaging systems. The paper reviews the development
effort of WINMOR (WINlink Message Over Radio) from motivation through tool development,
programming, testing and deployment in the WL2K system.
- Winlink 2000 – An Update
by Victor Poor W5SMM AAA9WL - Winlink Development Team
A lot has happened in the evolution of Winlink 2000 (WL2K) since the paper I presented at the Des
Moines DCC in 2004. That paper presented the then current architecture as well as the plans for changes
to accommodate ARES and RACES emergency operations. The purpose of this paper is to provide a
brief review of its current design and implementation.
- Clocking the Data
by Jerry Shirar N9XR
Many oscillators attached to the microprocessors and microcontrollers today are simply inverter stages
intended to become Pierce-style oscillators. There are still many options and design considerations to
make when attaching components onto the device to attain the desired results.
- A solar-powered telemetry system on base of a repeater
by Ioannis N. Vandikas SV2CPH - Technological Education Institute (T.E.I.) of Western Macedonia
This paper presents an approach for collecting and transmitting thermal and electrical properties of a
repeater, powered by a solar panel. The approach is characterized by high accuracy, low cost and low
power consumption. The approach incorporates 2 sensors for voltage measurement, 2 sensors for current
measurement 3 sensors for temperature measurement and one auxiliary sensor. We have found that the
aforementioned configuration facilitates the process of collecting accurate measurements from the
repeater. The core of the system is an MCU which collects measurements by converting analog signals
to digital. Then it processes them and creates digital packets in accordance with the AX.25 protocol.
Data is transmitted in a rate of 1200Baud with an AFSK configuration in the VHF zone. The data can be
decoded by any Narrow FM receiver with a TNC or by a computer with a sound card. The thermal
sensors offer an accuracy of 1oC, while the voltage sensor an accuracy of 0.1V. Finally yet importantly
the current sensor offers an accuracy of 0.18%.
- It’s the Network
by Erik Westgard, NY9D
Viewed in traditional Amateur Radio terms, the average cellular telephone handset is not very
impressive. It has limited RF power output, a fixed, built in antenna, and you can’t even select the operating
frequency. These devices do though leverage billions of dollars in worldwide network investment. Until
Amateur Radio starts to think beyond just home stations and at more fixed infrastructure and networking, our
emergency communications capabilities, particularly in the digital arena, will be limited.
- Using Udpcast to IP Multicast Data over Amateur Packet Radio Networks
by Paul D. Wiedemeier, Ph.D., KE5LKY and Clarke M. Williams, Jr. - The University of Louisiana at Monroe, Computer Science and Computer Information Systems Department
Traditional data transmission software, including Winlink 2000, AirMail, FTP, and SCP, use point-topoint
unicast to transmit data between two computers attached to the same network. Unfortunately
significant time is required to transmit data from one computer to multiple computers when using
unicast. During disasters and crises, minimizing the time to disseminate data is vital. Thus, to transmit
data efficiently, point-to-multipoint multicast data transmission software should be used. In this paper
we discuss how to multicast data over amateur packet radio networks using the Udpcast file transfer
tool. Udpcast was written for both the UNIX/Linux and Microsoft Windows operating systems, and is
widely used within the UNIX/Linux community to transmit operating system images from one computer
to multiple computers attached to the same network. Additionally, any computer can use the Udpcast
udp-sender and udp-receiver commands to transmit data or receive data. For these two main reasons, we
advocate using Udpcast to multicast data over amateur packet radio networks during emergencies.
- Writing for Publication — It’s Not Rocket Science
by Larry Wolfgang, WR1B - ARRL and QEX Editor
Potential authors have interesting projects or technical expertise to share with other Amateur
Radio operators, but they are reluctant to write an article for publication. Some authors may feel
intimidated by the prospect of submitting an article, while others see writing as time away from developing another project. Everyone has a story about something they have done, and those stories can be fascinating, but only if they are shared with others.
This presentation describes the basic steps involved in writing an article for publication. With a clear set of guidelines, more authors will be willing to take on the task of writing about their work and sharing their knowledge.
DVDs of the presentations at the 27th DCC are available: