At 10/22/2009 07:17, you wrote: >Gentlemen > >I am brainstorming about constructing a portable - temp use - Pelican Case >portable 2m repeater using the 6 meter Heliax duplexer concept. > >I had built a 6m duplexer for .5 mhz split using this method 12 years ago >and it worked quite well. > >I have built a single cavity 2m notch filter for APRS use, so I believe >the concept can work. > >Has anybody tried building a 2m duplexer using this method that would do a >600khz split? > >Advice, suggestions?
The problem I see is that, even at only 500 kHz split, the difference between the input & output in percent is much smaller at 2 meters than at 6. At 6 meters, the spacing is just under 1% of the operating frequency, while at 2 meters it's only 0.41%, so the required Q of the 2 meter duplexer will be more than double what's required @ 6 meters. Bob NO6B
