That's not quite true. It has to be an odd integer multiple of a quarter
wave to operate properly...that's 1/4, 3/4, 5/4, and so on. The antenna
itself is a quarter wave long, so if you want to use that as a template that
would work. A quarter wave in air is about 2.75 inches long.

Jim


"COLIN LAMB" wrote in message
ink.net...

I see I had a typo. The ground plane (disc) must be 1/4 wave in each
direction minimum. Greater diameter can be used, but is not necessary for
proper operation.