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FM radio antennas Answered

Are there any ideas out there for building an FM antenna booster that can be used with the usual whip antenna that comes built into most radios these days. Most of the radios are made in such a way that it is difficult to get at the internal wiring, so the booster would have to be an external unit.



10 years ago

Just about any of the rooftop TV antennas should pull in FM stations loud and clear without a booster; connect one of it's wires to your radio, or both if you have a radio with two screws for antenna wire. Even rabbit ears, stretched to 1.5 meters, and high up as possible, should be an improvement.

I have fooled around with TV boosters, not much with FM, but maybe it will give you some idea of what is required:

UHF TV Antenna Booster
Of course, this would need to be inserted into the circuit in question.
This is an UHF band TV antenna preamplifier circuit With 15dB gain that is easily built. The first stage is an band pass filter constructed by the C1, CV1, L1, L4, C7 and C3, the second stage is a base-common voltage amplifier with low input impedance to match. Build the L1 ~ L4 as air core coil to obtain high Q-Factor. You can find out about air core coil construction and calculation here. After assembling, pack it into a proper metallic box and connect the ground of the circuit to the box to reduce noise effect.

FM antenna booster schem.gif