1. The amplitude modulation frequency emission range is 600Khz-1500Khz. 2. External audio modulation signal, 3.5mm headphone jack. 3. This transmitter is a low-power transmitter, and the maximum receiving distance is about 5m. 4. Volume potentiometer with switch, which can realize modulation depth adjustment, that is, on-off function. 5. The power supply voltage is 5v-12v, which is powered by two lithium batteries and can be powered by an external DC stand. LED work indication. This transmitter is a weapon for assembly, debugging and maintenance of radios, radio stations and SDR receivers. AM transmitter Operation guide: Connect the audio signal to the rotary sliding potentiometer of the earphone holder and hear the noise. The LED lights up. Then adjust the frequency. It's DIY kits, needs to finish by yourself. Color: Green Material: PCB+Metal Package Contents: 1 * AM Emitter Board Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.