Wright's Aerials

Aerial photography - Ancient Gallery

I’m intrigued by this aerial. It appears to be an Antiference 8 element Band III array, but with a difference. The difference is that there are two driven elements. The one nearest to the mast looks very much like the Antiference ‘Trumatch’ double dipole, still in use on VHF-FM and DAB aerials. The ‘Trumatch’ has greater bandwidth than a conventional folded dipole, incidentally. The other driven element on this aerial is a simple halfwave dipole, mounted about a quarterwave back from the Trumatch. The feedpoint is a conventional Antiference junction box piggybacked onto the element fixing bolts of this rear dipole. I wonder if this aerial is designed to reject signals from the rear. Linking bars connects the two dipoles, and these are not phase crossed. A signal coming from the front should arrive at the feedpoint with both components—that received on the front dipole and that received on the rear one—in phase, apart from the slight error caused by the velocity factor of the linking bars. A signal coming from the rear should arrive with the two components 180° out of phase.

Previous   Next
Print this page © 2003-2012, Wrights Aerials Add to Favorites