Overview

The aim of this project is to archive interesting pirate and community radio transmissions on FM in London, in 2020 and beyond. We use FM radio receivers to make our recordings. We do not use the stations’ Internet streams for our uploads: if a recording is on our site, it was broadcast over London’s airwaves. If you are the owner of one of the mixes and would like it to be taken down, please get in touch via Twitter.

Pirate and community FM radio in London

History

Pirate radio, in short, is radio broadcasting without holding a license from the communications regulator. One of the earliest uses of this term dates back to the 1920s, when a station in Chicago was accused of being a “wave pirate” for broadcasting on an unassigned frequency.

UK pirate radio took off in the 1960s, with offshore ship-based stations such as Radio Caroline and Radio Northsea International broadcasting pop music that could not be heard on the national radio at the time. In the late 1970s, pirate radio stations moved into the inner cities, swapping long distance AM transmissions for shorter range but higher quality FM signals. The stations’ mission remained the same, however – to give voice to musicians and communities who could not secure airtime on mainstream channels. Of particular note is London’s Dread Broadcasting Corporation, credited as being the first Black music pirate radio station.

In the late 80s and early 90s, London-based pirate stations played a pivotal role in the emergence of rave culture. Pirates such as Fantasy FM and Centreforce pioneered acid house music on the airwaves, while the Weekend Rush, Kool FM, Impact FM, Pulse FM, Eruption and Rude FM championed hardcore, jungle and drum & bass. It is widely accepted that without these stations the above musical genres would have had a much smaller exposure or perhaps would not exist at all. The same can be said for UK garage, grime and dubstep, which were heavily supported by the likes of Upfront FM, Rinse FM and Flex FM in the late 90s and the early 2000s.

Today

While legal and risk-free Internet broadcasting has robbed the pirates of their monopoly on showcasing new underground music, many have decided to continue their FM transmissions. Stations such as Rinse FM and Flex FM have been able to obtain Ofcom’s community licenses and transition to permanent legal status, while some others have chosen to remain unlicensed.

Why record directly from FM?

The radio waves are part of the fabric of the city. While listening to Internet radio on smart devices is now the standard way, those driving around town or using their hi-fi audio equipment at home will still be scanning the FM dial. We seek to document this uniquely local experience, following in the footsteps of the pirate radio tape traders of the 90s and the current online archivists of such tapes.

Technical details

While we use a number of FM receivers positioned in different locations to make our recordings, our PC-based central monitoring station is responsible for the vast majority of these recordings. We use Software Defined Radio (SDR) technology to monitor and capture multiple FM signals simultaneously, on a continuous basis. These captures can be reviewed later and interesting broadcasts can be extracted and uploaded. You can think of this as a “Sky+ PVR box for FM radio”.

We use a Windows PC with a 6-core Intel i7 CPU running SDR# software. The SDR receivers are two AirSpy R2s and one AirSpy Mini. Each SDR is responsible for capturing a specific part of the FM radio spectrum, as shown on the above diagram. The antenna system we use is inspired by London Shortwave’s adaptation of the YouLoop antenna. The FM signals are amplified using a battery-powered wideband pre-amplifier prototype designed by AirSpy.

We run three copies of SDR#, each taking input from the corresponding AirSpy receiver. Each copy of SDR# is able to split the incoming part of the FM spectrum into separate “slices” corresponding to the individual stations, and record them to disk as WAV files. On average, we monitor and record around 20 stations simultaneously, which uses around 70% of the CPU and results in about 100 Gigabytes of WAV files per day. We also use some advanced SDR# features to enhance the signals of difficult-to-receive stations, similar to what is demonstrated in this example by London Shortwave.

How to cite this project

The London FM Dial Project, londonfmdial.org