Micro Power AM Transmitter 3 Channel 1MHz 3MHz 5MHz DIY Amplitude Modulation Transmitter with Antenna and Audio Cable 3.6V for Radio Receiver Player Testing

The media could not be loaded.  So a few weird quirks with this thing. It definitely works, but not with the audio cable provided. Using a spectrum analyzer I get signal on 5 MHz and 3 MHz individually by choosing channel 3 and 2 respectively. The quirk is that when you put it on channel 1 for 1 MHz, it transmits on all three frequencies at the same time reducing the overall signal on channel 1. Not sure if that's by design, but it really reduces the signal output. But if you replace the audio cable with a rechargeable Bluetooth dongle and set this right next to the AM stereo with it tuned to 1 MHz, it should pick up the signal. Move it 3 feet away and the signal is lost.I tried tracing continuity across jumpers, but no luck in finding why it feeds all three on channel 1 without taking it apart. I may swap the 5 MHz and 1 MHz since the intent is to use this for an old tube radio. Would give it more stars if it came with a diagram and a working audio cable

This thing didn't work. After looking at the design, there is no way it could work. It's a crystal oscillator and they are trying to modulate it by the supply voltage. It does put out a carrier but no modulation. In layman's terms, there is no sound.

No instructions how to make adjustments

Good way to send music to an old AM tube radio.