[160m] Antennas

[Tom W8JI]

>  I was thinking last night as i was listening to coast to coast on my
> AM radio.
>
> The question is,  While i know for sure we could not use it for
> transmitting,  But the ferrite bar antenna that is inside this radio,
> How efficient are these anyway?  I know they are highly directional,
> with very deep nulls.  But has anyone ever made one for use on 160 meters?
>
> And if so what did it perform like?

Good thinking. The small rod antenna has an overall pattern much like a 
small loop antenna. The rod length direction is like the axis of the small 
loop antenna, and would be the direction of nulls.

Unfortunately the are not highly directional, they are the opposite! The 
pattern has very narrow very deep nulls, but in all other directions it has 
strong response. This means the directivity is not good, only the nulls are 
sharp and deep.

It would be good for nulling noise or unwanted signals from a small specific 
area, but not much good if noise comes from multiple directions.

Efficiency is very low, very small fractions of one percent. This doesn't 
matter much for receiving, but it does for transmitting!

73 Tom