| RD - 356kHz - Reading, PA |
RD - 'SHAPP' in suburban Reading.
An outer-marker for Reading's airport (RDG), RD is as with many such beacons where it is because it has to be, rather than for convenience. Occupying a small corner lot in suburban Reading (Harding and Hancock Streets), RD has an almost unique antenna: It is a single 'phone pole of some 35' with cross-bars at the top and bottom between the ends of which are strung four vertical wires, connected in parallel. This is obviously to create an electrically 'fat' single radiator, which would be of lower 'Q' than a single wire. The benefit is not so much in radiating efficiency, but in ease of maintaining a match over a broader bandwidth, and by corollary not having to worry so much about antenna tuning following the environment. Possibly they can get by without automatic antenna tuning.
Some other pictures:
© Steve Dove, W3EEE, 2003,4,5