October 9-11, 2015, Chicago, Illinois
QRPi – A Raspberry Pi QRP TX Shield Design
By Zoltan Doczi, HA7DCD
Abstract: “Be Smart, Not Strong” this should be the self explaining phrase of the QRP term in amateur radio. Low power operation is always more difficult than using hundreds or thousands of watts RF power. But the smile on your face after the first thousands miles long QSO, using portions of one watt is worth the challenge! QRP enthusiasts instead of spending time and money on increasing power capabilities of its station prefer a smarter way: to learn about new modulations and coding techniques and applying them in everyday HAM operation practice.
Nowadays one of the most impressive QRP mode is Joe Taylor, K1JT’s WSPR (pronounced “whisper”). WSPR stands for “Weak Signal Propagation Reporter.” Programs written for WSPR mode designed for sending and receiving low-power transmissions to test propagation paths on the MF and HF and recently UHF bands. Users with internet access can watch results in real time at wsprnet.org
The QRPi board (or shield as referred by the community today) is an inexpensive way of turning a Raspberry Pi single-board computer into a QRP transmitter.
VOA Radiogram: Text and Images via Shortwave Broadcasting
By Kim Andrew Elliott, KD9XB
Abstract: The Internet has largely replaced shortwave radio for the broadcast of news and information across international boundaries. A growing number of countries, however, are blocking Internet content from abroad. As a possible workaround, digital text modes familiar to the amateur radio community can be used to broadcast news via existing shortwave transmitters and can be received on any shortwave radio, but software is required to decode the text. VOA Radiogram is a weekly Voice of America program experimenting with text and images through a shortwave broadcast transmitter
HF Receiver Testing: Issues & Advances
By Adam Farson, VA7OJ/AB4OJ
ARDEN, AMATEUR RADIO EMERGENCY DATA NETWORK
By Andre Hansen, K6AH
Abstract: Mesh technology has been around for over ten years. Over the past two years developers on the AREDN. team have advanced the art by porting Broadband-Hamnet’s extremely popular mesh firmware to the Ubiquiti airMAX line of commercial Wireless ISP routers. This has literally changed the complexion of mesh implementations from an experimental, hobby-oriented, novelty into a viable alternative network suitable for restoring some degree of Inter/intra-net connectivity when all else fails..
More recently, the developers of this software have kicked-off a new project, AREDN, focused on taking this technology to the next level in EMCOMM communications.
This paper begins with an introduction to the AREDN Project and mesh networking and concludes with a roadmap for the Project’s future. It dives into implementation techniques and considerations as well as avoidable pitfalls.
Feher Modulation 16 QAM
By Patrick Jungwirth, PhD
Abstract: We present simulations of conventional quadrature amplitude modulation (QAM) and Feher-QAM to estimate the bandwidth improvement for Feher-QAM. We show more than a 10% improvement (reduction) in bandwidth for Feher-QAM over conventional QAM. We also show the power spectral density for Feher-QAM has a much faster convergence than conventional QAM.
Conventional digital modulation techniques are limited by embedded rectangular windowing functions. Some more advanced modulation techniques utilize raised cosine windowing functions (filters) to improve sidelobes. Feher modulation uses a half cycle raised cosine waveform to reduce bandwidth and improve sidelobe attenuation. Feher modulation offers the equivalent power spectral density convergence of a raised cosine windowing function with twice the width (half the bandwidth). All symbol transitions in Feher modulation are smooth and occur at zero slope points. The smooth, zero slope transitions help improve intersymbol interference, and reduce timing jitter problems.
Update on DATV-Express exciter for Digital-ATV
By Ken Konechy, W6HHC
Abstract: The old technology of analog-ATV suffers from susceptibility to snow and multi-path ghost images. Digital-ATV (DATV) using new technologies like digital modulation, and Forward Error Correction (FEC) can result in robust video reception where analog-ATV fails, as well as providing more narrow bandwidths on the ham bands. This presentation will review progress by the DATV-Express Project Team since DCC2014. These new efforts include:
- Making the exciter more portable by Hardkernel ODROID U3 Single-Board-Computer
- Support of Narrow-BandWidth DATV down to 0.5 MHz
- Using Express_Server software to provide video by UDP
- DatvExpressServerApp software on Windows (no Linux)
- DatvExpressSdrApp software for FM and SSB (no Linux)
- A brief report on the European MiniTiouner USB-based Receiver Project
Measuring the Ionosphere at vertical incidence using Hermes, Alex, and Munin Open HPSDR and Gnuradio.
By Tom McDermott, N5EG
Abstract: This paper describes a monostatic method for measuring the vertical virtual height and the vertical velocity of the F-layer of the ionosphere. The equipment is simple and relatively low power, it uses the Open HPSDR Hermes transceiver module, Munin broadband Power Amplifier (PA), and Alex RF filter module. The antennas consist of a 40m dipole and antenna tuner for transmit and an active receive loop antenna. The software real-time processing (reception, windowing, and correlation) is done using Gnuradio on a Linux PC, followed by post-processing using a Python program (multiple sweep integration and plotting).
Arduino CAT Controller HPSDR
By John Melton, G0ORX/N6LYT
Abstract: Simple CAT coltroller for HPSDR using an Arduino micro-controller and a few switches and a step encoder.
ARDOP (Amateur Radio Digital Open Protocol)
By Rick Muething, KN6KB, Matthew Pitts, N8OHU and John Wiseman, GM8BPQ
Abstract: The popularity of low cost PCs and tablets with substantial DSP processing power and an increasing awareness of digital signal processing in the amateur community have created an explosion of digital modes. Some of the challenges this poses are lack of portability, inconsistent virtual TNC interfaces and protocols optimized for single uses. ARDOP is a new protocol development which was targeted to address these challenges. The development started in 2014 and Alpha testing of the ARDOP_Win TNC (Windows version) was begun in April 2015. From the beginning the protocol was designed to cover a wide spectrum of amateur uses and be fully documented with open sourced code to encourage learning, experimentation, evolution and portability to other platforms both software and hardware.
An OS Independent and Device-Independent Mobile Web Front Panel for Radio Transceivers
By Bruce Perens, K6BP
By Patrick Prescott, KC1AJT
Abstract: An in-depth look at mesh networking using repurposed WiFi equipment in FCC Part 97 Amateur Radio spectrum.
OpenWebRX: SDR Web Application for the Masses
By Andras Retzler, HA7ILM
Modulation . Demodulation Software Radio
By Alex Schwarz, VE7DXW, Guy Roels, ON6MU and Omar H. Longoria
Design of a Practical Handheld Software Radio: Part II
By Chris Testa, KD2BMH
Abstract: The design of a standalone battery powered Software Defined Radio (SDR) is presented. Three rounds of prototypes were designed, built, and tested over the last three years. The hardware architecture of the newest design is detailed, with the goal of getting the device into the field to build real RF links. The software stack, from the high-level websocket user interface down to the embedded Linux operating system are discussed. Finally, the latest work on the Field Programmable Gate Array (FPGA) modem are presented, including optimization work that drastically improves simulation performance.
Software Defined Radio Server
By Phil Theis, K3TUF
SatNOGS: Satellite Networked Open Ground Station
By Daniel J. White, Ph.D., AD0CQ
Abstract: The SatNOGS, or Satellite Network Open Ground Stations, project promotes and supports free and open space applications. It seeks to solve the problem of connecting many satellite users/observers to many ground station operators. Modern open software, web, and hardware techniques are used in implementing the Network, Database, Client, and Ground Station subprojects. Modularity in all the systems promotes the dual-use of ground stations by not interfering with local operation while utilizing the great amount of time a civilian, non-commercial ground station would otherwise sit idle.
The TASS RF Switch
By John Ackermann, N8UR
Abstract: A High Performance RF Switch for Lab and Hamshack
Bandwidth Requirements for Digital Voice
By Bryan Hoyer, K7UDR
Amateur Radio Voice and Data Network Interconnection
By John Hays, K7VE
Abstract: Bringing sanity to a disjointed landscape
SDRs and Stuff
By Steve Hicks, N5AC
- Phase noise considerations
- The ADC Overload Myth
- Noise Reduction Techniques
- Wideband Noise Blanking
- Digital Voice Modes
- SO2R / Full Duplex
Issues with the Open Hardware Model
By Bruce Perens, K6BP
Ham Radio — Now What?
By Ward Silver, N0AX
Abstract: Saturday Evening Banquet Speaker