What's this? (transmitter)?

[Radio Wrangler]

Thread re-opened at ToothyChris's request (another dentist tojoin Nick on the forum?)

From seeing the printed inductor, this looks like a VHF power oscillator design. From the choice of transistors, I'd reckon 1-3Watts which would make it rather detectable if operated, being orders of magnitude more powerful than things people put in their pantries.. It could be used on the 2 metre amateur band by someone with a grade of licence which allows home-made equipment, but the lack of a crystal makes it unlikely to be stable enough to be welcomed.

Cleaning it up would amount to a complete re-design.

I strongly recommend that no attempt is made to build one or power one up. I'm quite surprised it appeared in magazine adverts. The Band II FM broadcast band is routinely checked for pirates, and the adjacent air band is the most carefully protected spectrum of all. Any noticed unofficial signal gets reported to CAA and Ofcom almost immediately. This is also an open forum and may be read by one or two people on the official side of the fence.

David

[HamishBoxer]

I am guessing it is not a Fortop 432Mhz PA stage etc ? Used on 70cm TV.

[Toothy Chris]

Thread reactivated, for reasons which will become apparent....

As others have mentioned, this looks like an early Pantec FM transmitter. I also had one of these 3W devices, which was almost certainly the later version, which was advertised in many 80's electronics magazines. I must have bought it in the late 80s, and remember it also had the coil etched on the PCB.

I also seem to remember that it was quite unstable and very sproggy. I don't think I have it any more, but I did find a rather aged copy of the circuit diagram, in one of my old folders. The text is very small and faded, but I have managed to adjust the image to make it mostly readable.

I wouldn't recommend anyone using one of these, but for the purposes of archiving the circuit, here it is, for your amusement.

Chris

[Toothy Chris]

And here is one of the adverts.

[Radio Wrangler]

The advert says what it is intended to be, a 3W transmitter for 80-108MHz which contravenes the forum rules, so now we know what it is, the thread has to close.

Interesting that it once sold through many of the radio magazines, but very likely to get that official knock on the door if tried nowadays. Pirate broadcaster stuff, and the penalties for that have been scaled up with the intent of bankrupting businesses.

David