38th ARRL and TAPR Digital Communications Conference

September 20-22, 2019, Detroit, Michigan

PSAT2 DTMF Experiment APRStt – Touchtone® Digital Communications, Using any Radio for Data Exchange

By Bob Bruninga, WB4APR

Abstract: DTMF (Dual Tone Multi Frequency) (aka Touchtone®) signaling has been built into almost all Amateur Radios for decades and more recently cellphones, yet most hams do not make use of this powerful data entry and data exchange capability for their special events. They continue to use laborious voice directed nets and hand transcribed data. Although APRS brings an ideal digital communications capability to such applications, not all volunteers have the more expensive APRS capable radios. But they all have DTMF!

Proceedings Paper

Extending D-STAR with Codec 2

By Antony Chazapis, SV9OAN

Abstract: D-STAR was the first digital voice system designed by radio amateurs specifically for amateur radio use. However, it relies on a proprietary, patented codec, which has been the subject of controversy among amateur radio operators and regulatory authorities. In this paper, we present a protocol extension, that enables the optional use of Codec 2 in voice streams – an open-source and patentfree alternative to the default codec. The “D-STAR vocoder extension” has been implemented in a series of accompanying, open-source software projects, which focus on seamless interoperability with current D-STAR deployments. Transcoding voice streams between codec variants is possible with a custom version of the popular xlxd reflector. In addition, we introduce Estrella, a software-only, radio-like desktop and mobile application, for over-the-network communications.

Proceedings Paper

IPV6 for Amateur Radio

By Daniel Estévez, EA4GPZ / MØHXM

Abstract: Amateur radio operators have allocated the IPv4 AMPRNet block This is routinely used to support several operational networks and experiments, such as the Hamnet. With the increasing exhaustion of IPv4 address space and the goal of using and advancing state-of-the-art technology, it seems appropriate to start using IPv6 for this kind of Amateur activities. This paper gives a proposal of how to distribute IPv6 globally routable address space for Amateur radio use. We also explain some of the advantages of using IPv6, in comparison to the current IPv4 scheme.

Proceedings Paper

Synchronization in FT8

By Mike Hasselbeck, WB2FKO

Abstract: Deconstruction of the FT8 open-source FORTRAN code provides insight on the synchronization algorithm. The heart of the synchronization scheme is a Costas Array, a specially designed square matrix that was invented in 1965 to improve the reliability of underwater sonar. An intuitive explanation of the Costas Array is given, followed by a detailed description of its implementation in the FT8 decoder.

Proceedings Paper

WSPR in an educational Project

By Anthony Le Cren, F4GOH

Abstract: Since several years I have been trying to design projects to promote HAM radio,and especially for young people who want to pass their radio license. But most of the time, projects are complicated and require a good level of electronics. The article described below is for people who know to blink a led with an Arduino and wiring a breadboard.

Proceedings Paper

Portable Audio Frequency-Shift Keying Sensors using a Hamshield mini

By Nolan Pearce, KE8JCT, Stephen S. Hamilton, KJ5HY, and Kate J Duncan, KB2ZOO

Abstract: The newly developed Hamshield mini and commercially available electronic devices integrated with the Hamshield can be used to create an auto-reporting ham radio motion detector. Open-source Arduino code, a Passive Infrared (PIR) sensor, and looped audio frequency shift keying (AFSK) transmissions were assembled to create a low-power, low-cost, open library, small form-factor device that expands upon current automatic remote beacon sensors. In this paper, we detail an open-source amateur radio QRP VHF/UHF packet radio using the Hamshield. Furthermore, the compatibility with Arduino single-board microcontrollers will enable current amateur radio technologies.

Proceedings Paper

An FPGA Learning Experience: SPI Interface to Max10 FPGA

By Gregory Raven, KF5N

A story of learning FPGA technology with the evolution of a simple project.

Proceedings Paper

Modulation – Demodulation Software Radio

By Alex Schwarz, VE7DXW

Abstract: Can Earthquakes change and create Shortwave Propagation? (A 4-year study of measuring background noise and propagation concludes that this is the case.)

Proceedings Paper

How to Kill Packet-Radio & APRS? Come to Serbia! (Part 2)

By Miroslav “Misko” Skoric, YT7MPB

Abstract: In this paper, we continue analyzing pervasive failures in Serbian policymakers’ strange decisions, as well as continual country’s ham radio leadership wrongdoings – that all together significantly leads not only to the stagnation in development of VHF & UHF ham radio data infrastructure but also to possible extinction of anything else but contest in telegraphy and ‘fox-hunting.’

Proceedings Paper

GPS Watch Technology

By Darryl Smith, VK2TDS

Abstract: From what I can workout, I am a bit unusual in the ham radio world. In addition to being active in amateur radio, and being on the board of TAPR, I am a mad keen runner. I started running about four  years back, and have never looked back.

Proceedings Paper