Thanks go to Sam Hunt who has donated some ex. Met. Police UHF cavities that will allow the use of a state of the art pre-amp on the receiver of the D-Star repeater. These are quite large for 70cm and are well built.

The cavities need a some new coupling loops to make them usable. 40mm brass washers with 16mm holes were sourced by G0VRM and they were then fitted with a N socket, a hairpin of 1.25mm dia silver plated wire and a 1-10pF micrwave trimmer.

Although not optimized, the results from the first one completed look encouraging. With a 1.6MHz spacing, a notch of -37dB with an insertion loss of 0.8dB has been obtained and that according to www.repeaterbuilder.com is about as good as it gets.

We have enough cavities available to enable single antenna working and with that in mind a much better quality 70cm antenna is being sourced.