This has been an ongoing problem, and several different antennas have been tried, some have been successful, but not on every airplane. The comm antenna on a Long-EZ is in the vertical winglet. Unfortunately the winglets on a VariEze are just not big enough. Mike DeHate has an excellent radio. We recently talked to him from over 100 nm away and he sounded as though he was on our wing. He has the following antenna: He cut an ordinary piece of house wiring to 20 1/4" long, and pulled two strands of copper wire out of this piece.
These were inserted into a conduit which was installed on the trailing edge of the main gear. The center conductor of the RG58AU coax cable is soldered to the 20 l/4"length of copper wire that goes down the gear leg. The shield is soldered to the 20 1/4"length of copper wire that goes through the fuselage. Three ferrite beads are installed over the conduit per the sketch below. The beauty of this arrangement is that if it should break it is easy to pull out and replace.