I was considering starting a pirate radio in a town where only old people live (100-200 people) but I don't know how to boost its signal. I have seen tutorials on setting up a Raspberry Pi FM Transmitter which is perfect for me: cheap and digital! Problem? The range is rather low, just for 10- meters or so.
The studio would be located in the highest place in the center of the town, which has 1.5 miles radius on itself. Could I raise the raspberry pi signal that high? If not what are my best options to broadcast a signal up to 2 miles? Thanks in advance!
Oh, I'm well aware about the legal issues, this is for testing purposes only so don't worry. Btw, I don't have a lot of experience with electronics so tutorials for noobs would be also AWESOME!
That type of transmitter is not good for more than a few hundred feet. The spectrum out of that thing is the worst I've ever seen. If you try to amplify it to go that far, you will cause major interference.
This uses a dedicated FM transmitter chip along with the PI instead of trying to hack the PI to do something it's not designed to like the original tutorials. If you want about a mile range with this, you could add this kit onto the antenna: www.minikits.com.au/PHA-1-Amplifier
It will give about 50mW out, which could go a mile or two with a properly tuned antenna mounted very high. I wouldn't try to amplify it any more than that though because the spurious radiation from that chip is still not very good (but much better than the PI).
If I were you and looking to build something, I'd probably go with the DRFS06. It comes as a kit and prebuilt: dutchrfshop.nl/fm-broadcast.html
It's seems complicated, but the instructions are pretty thorough and the output signal quality is comparable to a pro station. If you want to broadcast in stereo, you'll need to add a stereo encoder or use a software program like airomate (your PC must support 192khz audio). If you want a hardware stereo encoder kit, I'd go with this: aareff.com/en/fm-transmitter-stereo-coder-kit.htm
It's the simplest encoder kit out there that doesn't use the shitty one chip design like BH1515F. You don't want those. Don't be tempted to order anything else from that company though, all there other products are shitty clones of another company.
DO NOT touch ANYTHING from aareff - his gear is just a bad copy of the old NRG stuff, and if you ever get what you ordered, it won't work properly. Visit radionecks.co.uk to find out about the aareff story.
The transmitter that you want is the one from DutchRFShop. It's nicely designed and works perfectly if correctly assembled. If you don't feel confident of soldering together a complex PCB, buy the ready-built version. It costs more, but it's built, tested and ready to go! They will also supply a stereo coder - they have several models at various prices.
You will also need an audio limiter. If you're going to broadcast pre-recorded programmes (perhaps from an MP3 player), you can use a software "normaliser" like the one included in Audacity. If you're going to do it in real time, you'll need a hardware audio limiter.
