Which type of Antennas are suited for a FM Transmiter Hunt competition ..Where you are required to find the exact position of the receiver ...The carrier frequency is also Unknown .....So we need a FM antenna with fair coverage ....Our first challenge is to identify the Carrier which we think simple tuning is suffiecient but how to sense the direction and distance .....
Will the loop antenna direction finding possible ........
The most common type of directional aerial for FM is a "Yagi", trouble is they are huge, like 2m long and 1.5 m wide, like a BIG TV aerial. If you are determined enough, you can with multiple matched receivers, delaying the output of one Rx then add the outputs. With this technique, you can then calculate the distance from you of the TX and its angle. be warned this calls for loads of expensive kit.
frank
The most common type of directional aerial for FM is a "Yagi", trouble is they are huge, like 2m long and 1.5 m wide, like a BIG TV aerial. If you are determined enough, you can with multiple matched receivers, delaying the output of one Rx then add the outputs. With this technique, you can then calculate the distance from you of the TX and its angle. be warned this calls for loads of expensive kit.
frank
Locating a FM transmitter consists of triangulation from at least two points in a territory. From both you find the azimuth angle, the transmitter should be located on the intersection of two-three azimuth lines.
As the FM range typically is 88-108 MHz, a standard Yagi and dipoles may not be practical for a field operation. Try to use a loop or double-loop antenna, like described in ARRL Antenna Book. In principle, you need not much gain but a well defined minimum from which you can find the azimuth at a spot.
The receiver you should use should have the RSSI output to indicate the minimum. You will have to use a well screened receiver, so it only processes the antenna output, not any wave reaching it. FM transmitters often emit high RF power levels, so be ready to use a 10- or 20-dB coaxial attenuator on the line from antenna to receiver.