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

    RC Charger
    Logic Probe
    Regulator Loss Cutter Circuit
    Bench Power Supply I circuit diagram
    lead acid battery regulator for
    6N7 Tube QRP Power Amplifier
    Digital Stopwatch 0-99sec
    start up aid for pcs
    Vacuum Technology for Home-Built Gas Lasers
    Motor vehicle steering flasher 12
    The Full-Wave Rectifier and Averaging Filter
    Units from the MAX4100 4101 gain buffer circuit diagram