Uncle Peter wrote:

Must be interesting as the rear elements start approaching
odd-multiples of the wavelength of the operating frequency..



LPs don't care!!

They are a driven array and fed from the shortest wavelength. So, as the
active region becomes resonant the RF Power is radiated by the active
region. The portion of the energy that 'sneaks by' the active region is
negligible.

Check the Tennadyne site: http://www.tennadyne.com and the ARRL
Antenna Handbook.