random aerial question

[Geoff]

hi guys,


just out of my need to know stuff, what are those big (diameter) aerials you see mounted to the rear of 4wd's and caravans?


Cheers

[JDNSW]

I think what you are referring to are HF aerials.
John

[slug_burner]

As a bove HF antenna, tuning network/mechanism contributes the the size. Usually the bottom part is thicker.

[Geoff]

ahhhh, thanks

[jim bolton]

Hi Geoff, have a look at "screwdriver aerial" I think this is what you've seen. The large diameter bit at the bottom contains a coil which is tuned by contacts moving up and down it driven by an electric screwdriver motor in the original version. Cheers, Jim.