Separate Feed Line Multiband Antenna Advantages by Mark, K1RX
an excellent way to optimize the entry level Single Operator, Two Radio (SO2R) contest station.
YES – You can operate two bands at high power with only a few feet of separation between the feed points on an antenna (does require Bandpass Filters to protect the radios). Now removing this concern, one can incorporate some nice advantages to the station.
The most obvious advantage when using a multiband single antenna, pointed toward the high population regions of the world, at a time when all of the bands are open is BIG. Using an antenna with separate feed lines for 20, 15, 10 M provides a simple, cost effective solution for simultaneous contact production.
Having a single antenna that operates on multiple bands simultaneously clearly carries several advantages:
Smaller wind load on tower with fewer antennas (compared with having multiple, single band (monobanders) stacked on the tower),
Separate feedline designed multiband antennas help lower the overall station cost (no triplexer required or separate monoband antennas).
This limited space solution in combination with convenient antenna switching and selection will make for a competitive station. Simple yet highly flexible.
One potential station configuration that would nicely support SO2R operation would only require (in addition to the radios and computer interface) a set of Low Power (100 to 200 watt rating) Bandpass Filters (20, 15, 10, and the low bands) and Antenna switching.
Perhaps the simplest arrangement might be to divide the station band coverage with one radio that only operates 80, 20, 10 and the other radio operate 160, 40, and 15 M.
As bands open and close, the band change process is alternating between the two radios.
This arrangement is the simplest way to achieve a competitive setup.
More elaborate and automated configurations can also be designed too with 2 X 6 switches (two radios and 6 antenna choices) that allow either radio to operate any of the bands (very convenient). There are many options to consider.
Momobeam produces a number of triband and quadband antennas with separate feedlines for these applications.