At 7/20/2010 07:51, you wrote: >OK, too much interperatation based on a lack of information. > >For 2 antennas you need vertical seperation (best) or horizantal seperation >(very large), or 2 bandpass filters, one for each transceiver. > >Easiest solution, if you have the vertical real estate, use at least 25-30 >ft seperation (preferably 40-50ft) between the antennas. >I prefer to use top of lower antenna to bottom of top antenna as the >measurement of distance. Charts often say "center of antenna radiation". >Horizontal seperation would require 300' for the same amount of isolation. >Next best is a lesser amount of vertical seperation, coupled with bandpass >cavities.
Another option is a combination of pass cavities & directional antennas. I once successfully ran a 2 meter 600 kHz split repeater with nothing more than 1 pass cavity, an omni TX & Yagi RX antenna about 50 ft. apart horizontally. The TX & RX used tubes, & required weekly tuning & precise aiming of the Yagi's null into the omni to keep the desense away. But it worked. If your target stations on either packet frequency are all in one direction, a directional antenna may lessen your filtering needs. Bob NO6B
