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Were Horizontal Antennas Directional?

T

trusty

The following question was brought up after reading some old articles that the reason for the switch from 2 towers supporting a horizontal wire between them to 1 vertical tower/antenna was that "too much signal was being radiated into space":

Did the old horizontal antenna send out a directional signal with most of the signal being radiated perpendicular to the wire? (It would seem that the ends of the antenna would be somewhat nulled.)
 
Look up "Dipole Antennas".

There are three issues with a horizontal wire:
1. It is a directional antenna in the horizontal direction. That is, perpendicular to the wire. Great if you needed to run a directional pattern but otherwise you lose signal off of both ends.
2. It also radiated perpendicular to the wire in the vertical direction as well. That is why you hear the "radiate into space". That can be nulled out by placing the wire the correct height above the ground. But at AM frequencies my quick guess is that it is about 250 feet.
3. A dipole needs to be twice as long as a vertical for the same frequency (since you can use
ground for the other half of the dipole with a vertical). Takes up a lot of room. The last station in the US that I knpw of that uses a dipole has it wrapped so as to take up less space.

So bascially vertical has been the antenna of choice for AM frequencies. FM and TV is different for other reasons.
 
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