Part 15 AM outdoor installations tend to utilize bottom loading of the 3-meter vertical antenna for a number of practical reasons, such as listed here:
1.) the Part 15.219 3-meter rule can best be met by mounting the transmitter near the ground and close to the antenna;
2.) being close to the ground the power and audio connections can be conveniently brought to the transmitter.
But we hear stories of security, resulting in stolen or damaged transmitters due to their easy access by intruders. To increase security for an outdoor installation a transmitter mounted 10-feet in the air at the top of the antenna would be more difficult for vandals.
Difficulties of top-mounting/loading a part 15 system are listed here:
1.) getting power and audio up to the transmitter;
2.) grounding.
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