Andy, You first have to decide if you will use horizontal or vertical polarization - vertical polarization mostly for working the repeaters on 2M and 70CM, or horizontal polarization for working SSB stations.
Omnidirectionality is easy with vertical polarization but much more difficult with horizontal polarization. If you will be working repeaters, you do not need much antenna gain, but for SSB, you need much more gain. The other question is the feedline. What transceiver are you using? Does it have separate antenna outputs for 2M and 70 CM? For example, on the IC-706MKIIG, the 2M and 70 CM antenna outputs are combined, so you can use a diplexer to send the RF to the two antennas from a single feedline. The 6M output is combined with the HF output, so that requires a separate feedline. You probably want horizontal polarization for 6M, and an aluminum dipole would be self-supporting. If you use two at 90 degrees and switch feedlines with a switch, you have omnidirectional coverage on 6M. On 2m and 70 CM horizontal polarization, I use bi-directional skeleton slots for each band, which gives me enough gain for DX, mount two at 90 degrees to each other and just switch feedlines for omnidirectional coverage. If all you are interested in is working repeaters, then a dipole for 6M and commercial 5/8 wavelength verticals for FM on 2M and 70CM will work with one feedline if diplexers are available to split 6M and 2m/70CM. Again, much depends on the antenna outputs of the transceiver, whether you should use a single feedline or two feedlines. 73, Skip KH6TY On 7/20/2010 8:58 PM, obrienaj wrote: > > > I am planning another HF installation soon and may have a 33ft mast > begging for some extra creative thing to hang off it . I do not do 70cm > -2M-6M much and think I should , just to be able to get out when there > are bands openings. Nothing with DX in mind, just something > omni-directional would do (or ANY direction) I was thinking about a > fan-type dipole , one feed line going to dipoles for 70cm - 2M - 6M and > maybe 10M. Most likely not fully horizontal , more of a sloper. Any > thoughts on something like this? Quite a wide range of frequencies. > > Andy K3UK
