FM Transmitter

When I was a real little kid I always speculated as to how hilarious it would be to get a radio transmitter and talk shit on the bus driver channels and muck up other people's FM radios.

I guess, in some ways, that lead to my acquisition of an amateur radio license, call sign VK8NPF.

But with an amateur license, you still aren't allowed to muck around with bus drivers and neighbours, which is a pity really (haha, no just joking. That is illegal stuff).

Just in case you haven't seen a radio before...

But there is a loophole through the legality crap. The communications authority allows the use of the FM broadcast band for anyone, provided they don't "cause harmful interference" and also there are power limits too. That's just to make sure you don't rock up with a 50,000W transmitter outside someone's house and fry their electronic devices.

So yes, you CAN muck around with your neighbours after all! Saying hello through their radio isn't exactly harmful interference, so That's okay.

But I won't include the electrical schematic diagram for you here in case you actually build one and end up killing someone because you have the wrong frequency. Anyway, they are all over net, so you really shouldn't be coming here to scab a circuit diagram.

So I'll skip straight to the finished product. By the way, I don't consider this a proper project, since it took like an hour to make.

Oh, the lecturer at CDU, Rob, gave me the main circuit board in the form of a kit, so I really hardly had to do anything here. It is an FM transmitter with an output power of perhaps 5mW from what I can tell. That's maybe enough to go about 60m... good enough.

First I had to modify it to be powered from one of those rectangular 9V batteries, and also to add an external frequency adjust knob.

Then a case was made, with an adjustable knob fitted to the board.

Here it is all packed up in a compact case.

And the completed transmitter, with extendable antenna (~70cm). The adjustable knob is the black thing that isn't mounted properly. Hey, its a pretty good effort for an hours worth of work. Haha, see all the holes in the wrong places.

And it works. I've mucked around a bit with the neighbours while they were listening to the ABC News. They kept trying to retune their radio... bahahaha.