It is a 200 Ohm antenna.
So it is. Anyway, the question arose as I'd never seen anything other
than 50 ohms used for the balun.
Anyway, I spent all day on the 8 baluns (4 for 432 MHz and 4 for 144
MHz) and did as Owen suggested - put 1" PE irrigation pipe over the
baluns. Let's see the little so-and-sos eat through that!!
Alan