Transmitting WSPR Reports

The WSPR (Weak Signal Propagation Reporter, pronounced ‘whisper’) radio transmission technique was developed to enable considerable distances to be spanned using low power and minimum bandwidth. This article shows how you too can transmit WSPR reports using the Elektor SDR Shield and free software.

Software Defined Radio allows you to create receivers for any radio signal. You just need a single peripheral connected to your personal computer. HackRF One, is such a SDR peripheral, connected through USB. It receives or transmits signals from 1 MHz to 6 GHz. Designed to enable test and development of modern and next generation radio technologies, HackRF One is an open source hardware platform that can also be programmed for stand-alone operation.

LimeSDR Mini -- Functions Maxi! A pocket-sized SDR for transmitting and receiving

Author Burkhard Kainka’s inspiring Foreword in the book I’m reviewing here has important clues as to why software defined radio (SDR) is a hit not only among existing radio amateurs. SDR has proven to be a great promotion tool for the declining radio hobby in general. Since the tuning and decoding of shortwave radio signals is now done with a minimum of hardware and powerful (free) software, it’s easy to see why newcomers to the radio hobby and others with “DC minds” or with “deep fears of RF” have been totally captured by the concept of SDR.

Software-defined radio (SDR) offers an alternative design approach compared to traditional radio frequency (RF) design techniques. This article explores how SDR enables engineers to build radios that can react more readily to interference, employ more sophisticated channel-coding schemes to increase data rates, and take advantage of other advanced RF technologies.

This concluding part of our series on the Elektor SDR Shield 2.0 [1] is also the start of a new beginning. This automatically tunable receiver with two controllable VFO outputs opens up countless new opportunities, several of which are discussed in the article.

The SDR Shield 2.0 introduced in ElektorLabs Magazine edition 4/2018 offers a broad range of opportunities, not only for broadcast reception but also for amateur radio applications. You can hear SSB signals, also listen to CW and numerous digital signals for which you will need additional software to be able to decode them.

Analog Devices’ ADALM-PLUTO SDR Active Learning Module (PlutoSDR) introduces the fundamentals of software-defined radio (SDR), radio frequency (RF), and wireless communications to electrical engineering students. Designed for all levels and backgrounds, students can use this self-contained, portable RF lab in an instructor-led or self-led setting. When used with a laptop or tablet, the PlutoSDR serves as a personal portable lab that augments learning in the classroom. PlutoSDR supports the MATLAB® and Simulink® software packages. These software packages are claimed by AD “to feature an innovative graphical user interface (GUI) enabling students to learn faster, work faster, and explore more.”

One LimeSDR Mini from Lime Micro and one Raspberry Pi Zero have been used to create an open-source pocket-sized DVB (digital video broadcasting) transmitter, which is believed to be is the world’s smallest. Developed by Evariste Okcestbon, the open-source prototype streams live images from a Raspberry Pi camera (PiCam) and implements avc2ts, dvb2iq and limetx software to encode and transmit H.264 video on the 1.2-GHz (23 cm) amateur TV band. The boards are connected via USB, with the Raspberry Pi Zero board measuring 65 x 30 mm and the LimeSDR Mini measuring 69 x 31 mm.

A new kit jointly created by Lime Microsystems and seeed studio is claimed to provide everything you need to get started learning SDR basics and developing IoT applications. The Grove Starter Kit for LimeSDR Mini is targeted at educational use and for beginners, and carries a price tag of $249. Besides the LimeSDR building block optimised for 433/868/915 MHz and the associate antennas, the kit also contains an array of Grove sensors and output-related boards from seeed studios. The computing power for the software defined radio (SDR) is afforded by a GrovePi+ and a Raspberry Pi (2, 3 or Zero can be used).