In message , gareth
writes

"Fred Roberts" wrote in message
...
On 28/11/2015 22:11, gareth wrote:
Spike recently commented upon his success with DX by implementing at
the base of his vertical antenna a fan of 300 ground wires pointing
in the direction that he wished to work.

I've not seen my suggestion before, but why could one not just have a
1/4 wave vertical, with the other 1/4 wave making up the dipole being
rotatable for the desired direction of working?

This was covered in, IIRC, Pat Hawkers Technical Topics many years ago.
The Americans had done some research on this very topic during the Vietnam
war, if one bends a vertical dipole so that the two elements are at right
angles to each other it is possible it would seem to get some directivity
in the direction of the horizontal element.

Thinking about how drooping the radials on a ground plane brings
the feed impedance from 35 up to 50 ohms, I presume that bending a dipole
has
the same type of effect of reducing down from 72 ohms?

To get near 72 ohms, you would need to have the radials vertically
downwards - so essentially you would have the makings of a centre-fed
sleeve dipole. However, a side-effect would be that the coax would be
fairly lively at RF, and if you didn't want to live with it, additional
decoupling would be needed to kill it off.




--
Ian