Thanks for the input, everyone. Here are my comments:

Power will not be the largest issue here. It will be the high voltage,
which will be approx. twice the max. end voltage of a dipole (while one
end is at highest pos.V, the other is at highest neg.V). Using a relay
will also pose a problem with arcing over to the relay coil and the
control cable.

In view of this I was hoping someone might have alternative
suggestions, such as a home-made, remotely controlled HV-switch. For
example, a motor that could use a screwing mechanism to close a contact
or to open it - up to a few cm/in gap.

There are some suggestions to use a 1/4 wl stub, where opening at one
end would pose a zero impedance at the other. But won't I still have
the same problem with high voltages - simply moved to the end of the
stub instead at the antenna gap?

Again - thanks for the input and feel free to contribute further.

73 - TF3KX


TF3KX wrote:
Hello:

I am contemplating constructing an antenna where a center-fed HALF WAVE
will be bent in a loop, only to be isolated at the almost-touching ends
by a relay or some other means of a remotely controlled switch. When
the relay contacts are open I will have very high RF voltages between
the contacts, probably "a few KV" or even more. Are there any
suggestions on where I could find a relay, if any, for this? Or any
other means for doing this? An additional constraint is that the
switching device needs to be light and small (say, 1-2 oz or 20-50
grams). Some ideas I have come up with a

- A small vacuum relay (supplier, type?).
- A home-made relay, providing more contact spacing than usually
available.
- A DC-motor (toy-type) driven mechanism to open and close contacts.
- A mercury switch that could be tilted to make or break the contacts.
- A string-operated switch to open and close the contacts (would run up
the antenna mast).

Any comments or suggestions?

73 - Kristinn, TF3KX