[South Florida DX Association] The MacTenna - "Simple Beam" uses a patented switching technology...

[Bill]

http://www.mactenna.net/simpleBeam.htm

The control signals to the "Simple Beam" are sent over the coaxial feed 
line. The antenna band is selected by a small controller located at the 
operating position. Because the "Simple Beam" is a wide spaced 50 Ohm 
design, there is no need to continuously change the element lengths as 
operating is changed. This eliminates the need for a serial 
communication link between the the rig and the antenna controller as is 
required with close spaced, narrow bandwidth, motorized antennas. This 
means that the "Simple Beam" will work with all radios made in the past, 
present, or in the future.

The "Simple Beam" provides superior performance compared to close 
spaced, motorized beams as well as many multi band beams with up to 12 
elements. No traps or matching networks are required with the "Simple 
Beam". We call it the "Simple Beam" because it is simple.