3-Element Cage Monopole
Posted on December 24, 2010
This 3-element cage monopole is 3-wire antennas in parallel, spaced 1.5″ apart in a triangular vertical pattern, lifted toward the ceiling by a 3-leg bamboo tower rising from a triangular particle board base. At the top a triangular support for the wires is built from 3-corks stuck together with round tooth-picks and lightly glued to the top of the bamboo struts. The wires hang and at the bottom are held in place by a second triangular arrangement of corks & tooth-picks, below which the 3-wires flow together at a solder junction and are attached to a Wholehouse 2.0 with a clip-lead from the short antenna lead. The transmitter hangs below the antenna wire assembly by means of a plastic sock-hanging hook, large paper clip formed into a triangle keyed into the Wholehouse belt clip.
Operating frequency is 107.1mHz half-wave 55.14055″ antenna length.
On the open carrier I distinctly hear the 100kW station at 107.9mHz, whose transmitter is about 2-miles away. Perhaps my wires are cut a little short, and maybe if lengthened the unwanted signal might de-tune.
Of course putting 3-verticals in parallel lowers the impedance of the antenna, and the actual impedance of the Wholehouse Output is unknown.
Of course the advantage of a cage monopole is to provide a wider bandwidth antenna, but I’m not sure that it improves the outreach.
The reception meter on the Techniques Tuner, some 75 away, is 3.25 on a scale of 5.
C.Crane Plus located 12-feet away full meter reading.
Grundig portable FR-200 with antenna folded, good signal to 30-feet.
I would like also to have horizontal polarization, but how can this be done?