Small Radio Transmitters


Posted on Feb 4, 2014

Information about building a small radio transmitter, which has a PCB 1. 75` x 2. 5` (45mm x 68 mm) and has a range of about 30 yards or so. The documentation with the circuit says the freq range is 100-108 MHz, but I have found it to be more like 85-100 MHz. The circuit is (of course) only mono, and accepts an audio input from either a mic


Small Radio Transmitters
Click here to download the full size of the above Circuit.

rophone or other source. The input impedance is 1Mohm. The input sensitivity is 5mV and the max input signal is 10mV. The transmitted signal can be picked up on a FM radio. The circuit can be used for short-range transmission, eg. for wireless microphones. The actual circuit comes from a `Kit`, available from Veleman electronics (USA distributor is Tapto Corp. , PO Box 1339, CLAREMONT NH-03743-US. UK distributor is High-Q Electronics, 382 Edgware Road, London, W2 1EB). The kit number is K1771. It is a very good transmitter. I bought the kit, and made the circuit, which worked very well. I wanted two transmitters, so I made my own `copy` PCB and built the circuit, and in fact my home-made version seems to work better than the original! So there is no need to buy the kit really, as it is quite a simple circuit, and is the best `home-made` transmitter I have seen. PCBPLAN. GIF shows the PCB layout from above (components shown). PCBPLAN. GIF is an accurate layout, scanned from the instruction sheet. I have used * to mark one corner for reference. TRACKS. GIF shows the track layout on the soldering side of the board. This is NOT a very accurate layout. This is because I didn`t actually have a plan of the track layout. To get TRACKS. GIF, I put a bit of OHP film onto the bottom of the PCB, and traced the tracks with an OHP pen. I then scanned this in. I have marked the component leg holes (approximately) with white blobs. Then...




Leave Comment

characters left:

Related Circuits

  • New Circuits

    .

     


    Popular Circuits

    Capacitance meter with 555
    Audio Car Stereo Audio Amplifier with TDA1553CQ
    Solar power related schematics
    3 volts car adapter using lt1074ct
    Oscillators and Mixers
    Scmitt Trigger circuit using NE 555
    Panic Alarm Circuit
    Atmel 89C2051 In-Circuit Programmer
    Super lock circuit diagram



    Top