Hey folks

im looking around for an AM transmitter, they have some nice ones on ebay for about $250 but can't afford it, so was wondering if you guys ever tried the cheap ones on ebay? They are about $50.

Thankyou

Steven.

The kit HRSA have is less than $50, easy to assemble and works well.
A good little project.
JJ

The one most commonly on Ebay, usually showing a small PCB with a couple of small condensers on it, doesn't work on its own, and has to be fitted to a modified radio, which then becomes the transmitter. As per the above comment, the HRSA (and others) offer kits for a self-contained transmitter.

Some years ago now, I bought one from England - it runs two Russian valves on a small, well designed PCB with an RCA socket for the audio input and terminals for the A and B batteries and antenna. I mounted the PCB on a polished breadboard alongside battery holders, with the A battery being two D-cells in parallel and the B battery being three 9-volt transistor batteries in series. I don't know if this one is still available but if I can find the photo I know I took of it back when it was built I will link to it here.

Don't expect any design to broadcast far and wide - most are flea-power designs to avoid interference being pushed to neighbours, etc. Though if you knew what you were doing, it is easy enough to beef up the output power, but it would risk a confrontation with the ACMA.

Its probably way too hard but for a laugh look in special projects where I described the building of two different "in house transmitters" using valves.
I suspect both would be slightly illegal, if anybody actually cared about the BC band now!

Fred.

Some years ago now, I bought one from England - it runs two Russian valves on a small, well designed PCB

This one -- now "retired". I built one, too, but I purchased the optional power supply as well.

https://www.6v6.co.uk/vcomp/pages/itxkit.htm

Don't have to be overly complex I built one of fixed frequency where the oscillator was a crystal locked one using 1/3 of a quad NAND gate & the modulator was a dual gate FET

Those British ones are really expensive. The 5-15W one is almost $600.

I was fortunate enough to have been donated a kit, which I put together and it works really well. I have no idea of the power output, but with a stray wire hung around the lounge room it covers the house and reaches out to the closest neighbours. It has a crystal-locked PLL, where the output channel is selected by dip switches, so therefore ultra stable. Very impressed with it. Unfortunately no longer for sale.

I was thinking about the possibilities of converting a valve radio into a transmitter, and worked out various things, but never did anything.