Over on YouTube the Radio Society of Great Britain (RSGB) has uploaded a talk by Noel Matthews (G8GTZ) titled "The Farnham WebSDR: DC to Microwaves on your smartphone". The Farnham WebSDR runs 8 (soon to be 10) RTL-SDR dongles in order to cover multiple bands from DC to 2 GHz.
If you're interested in their talks, the RSGB also recently uploaded several other amateur radio related talks from their 2018 convention to their YouTube channel.
This presentation gives an overview of the Farnham WebSDR (http://farnham-sdr.com/) which currently covers the LF bands through to 10GHz. The presentation describes the system architecture and antennas currently used on each band and how the team has used RTL dongle receivers, available for under £10, to give good RF performance on all bands from DC to 10GHz. There is a demonstration of the SDR in use on both PC and smartphone.
RSGB 2018 Convention lecture - The Farnham WebSDR: DC to Microwaves on your smartphone
The WebSDR from the University of Twente, Netherlands is a wideband HF SDR that is accessible from all over the world via the internet. It was first activated in 2008 making it the very first WebSDR ever. The creator of the service Pieter-Tjerk de Boer PA3FWM has recently made available spectrum image archives which show the HF band conditions over the last two years.
The X axis represents the frequency and the Y axis is the time of day, starting at the top. Conventional wisdom about band behaviour can be easily confirmed by watching this video: the 60m, 49m and 41m bands are mostly active after dark, with the 60m and the 49m bands being generally busier during the winter months. The 31m band is most active around sunset, but carries on all night until a few hours after sunrise. The 25m band is active during sunrise and for a few hours afterwards, and around sunset during the winter months, but carries on all night during the summer. Peak activity on the 22m and 19m bands is also clustered bi-modally around the morning and the evening hours, though somewhat closer to the middle of the day than on the 31m and the 25m bands. The 16m band is mostly active during the daylight hours and the 13m band is quiet throughout the year except for the occasional ham contest.
[Fast] Visualising shortwave band activity throughout the year
Visualising shortwave band activity throughout the year
On this episode of Hak5 (a popular hacking and security themed YouTube channel) Darren and Shannon discuss OpenWebRX, a SDR web broadcasting and remote control tool that is compatible with the RTL-SDR. OpenWebRX is similar to the WebSDR software in that it allows people to connect to remote SDR’s on the internet and tune them to any station within their currently set bandwidth frequency range. Many already functioning online OpenWebRX receivers can be found in the database at sdr.hu.
In the first part of the video the Hak5 team explore the worldwide SDR’s on the sdr.hu website. Then in the second part they show a demonstration on how to install the OpenWebRX software in order to create a SDR broadcast with an RTL-SDR.
FREE SDR receivers all around the world with OpenWebRX – Hak5 1916
Recently Kristian, a reader of our blog wrote in to let us know about a new software project he found that allows you to use your RTL-SDR remotely through a web interface. The web interface runs on Linux and uses mysql and the Apache server to work. Currently it can be used to access options for rtl_fm, rtl_tcp, dump1090 and can also be used to create an icecast audio stream.
The software can be downloaded from its Git at https://github.com/sixuniform/yousdr. The instructions on the GitHub page show how to set it up on a Raspberry Pi running Raspbian, but the instructions should also be valid for other Linux distributions. As the software is new the authors are welcoming any improvements and feedback.
Some similar web based RTL-SDR remote control software that you may be interested in includes WebRadio and rtl_fm_python.
Mike Stirling has just released a still in-development version of his Linux based WebRadio software, which supports the RTL-SDR. WebRadio allows someone to connect to a remote RTL-SDR device via a web interface over the internet, much like WebSDR.
YouTube user opilarczyk has posted a video comparing HF performance of the rtl-sdr with the direct sampling mod at 7MHz with WebSDR, an online SDR streaming site. The comparison shows how the direct sampling mod is extremely susceptible to broadcast FM interference.
RTL-SDR gqrx direct sampling vs WebSDR on rtl2832u