I note that Radio Shack is supporting the guys at Maker Media in California with some excellent "how to" projects for the home constructor. Two of the projects involve making your own FM radio transmitter. The first one is a tiny low-power mono circuit, with a range of just a few feet. The video of how to built it is beautifully filmed.
And then, for the owners of the Raspberry Pi computer, there's a hack to turn that it into an FM station too. Thought they don't say what the radiated power is, if you built the right antenna, and you are on the right terrain, the signal may go for a couple of hundred metres. I wonder why they are not dropping Raspberry Pi's into some of the fragile states to assist opposition groups. Of course there is a disclaimer in both videos that transmitting on FM without a licence can end up with a fine or a jail sentence.
This simple hack turns your Raspberry Pi into a FM transmitter!
PiFM software enhances the capability of your Pi, but does so with nothing more than a single length of wire. This hack starts with the absolute minimum you need to run a Raspberry Pi — an SD card, a power source, and the board itself — and adds one piece of wire. It’s the coolest Pi hack with so few materials.
PiFM was originally created by Oliver Mattos and Oskar Weigl, and revised by Ryan Grassel. It was written by MAKE Labs engineering intern Wynter Woods.
MAKE labs give advice on which frequency to choose. 88-108 MHz is the range for FM in most countries (except Japan). That reminds me of the pirates I bumped into at the Picnic Festival in Amsterdam a few years ago. Radio Manuela 109 MHz was a small team of Djs and presenters who were busy interviewing VIP's at the festival. When I asked them if they had any listeners on 109 MHz, they said no. That wasn't the point. They wanted to get in to the festival and being from the media got them access to the people they wanted to see. They did have a low-power transmitter on 109 MHz, but they pointed to the slogan on the stand. We keep you young, sexy but not famous.
Best low power microstation I ever met was George FM in Auckland, New Zealand. They are part of this programme (around 24 minutes in) that I made in January 2000. They were operating then with 300 milliWatts, but into an antenna which was cleverly positioned so it covers most of the centre of Auckland where the students live. Looks like they are still on the air.
We also made a Media Network programme on the London pirates in October 1984.
And lastly a programme from 1995 when we looked at the pirate radio stations on AM (mediumwave) in the East of the Netherlands. They often used powers of 1-10 kW's rather than the couple of milliwatts you'll get out of a Raspberry Pi.