Dave, I'm not familiar with that particular duplexer, but I will take a stab at this. I have had some experience adding to duplexers, re-cabling, etc.
I am assuming the additional cans are identical to the ones used in your duplexer and that if there is a difference between high pass and low pass cans that you have one additional of each. You should be able to get at least 100 dB with the additional cans. If the original is really giving 80 dB at your frequency separation, theoretically you may see 120 dB. The cabling will have to be exactly right to see that much, and you'd better have very well shielded cables everywhere or leakage may spoil the 120 dB notches. Insertion loss should increase about 50%. If it is 2 dB now, it should be about 3 dB with the added cans. I would duplicate the cable type and length that is used between the existing cans. Use the same connector types also. And if there are T connectors on the cans, use the same type. Good luck and let us know your results when you're finished! 73, Paul N1BUG David Struebel wrote: > > > I have a Phelps Dodge 506-1 four cavity duplexer. Just recently picked > up two > additional cavities from someone who was parting out his duplexer... all > cavities > are BP/BR... Would like to add these to the duplexer to get additional > isolation. > The original duplexer is spec'd at 80 dB isolation... What do you think > I can get with the two > additional cans? I realize the insertion loss will be higher.. Any > idea how much? > The cabling between the cans is still 1/4 wavelength in coax, right?? > since I > will have to add some cabling...I have seen some discussion in the > duplexer info on the site > about maybe using a diffrent length cable when adding more cavities... > Can anyone comment on > all this? > > > Dave WB2FTX > > > > > > ------------------------------------------------------------------------ > > > No virus found in this outgoing message. > Checked by AVG - www.avg.com > Version: 8.5.325 / Virus Database: 270.12.26/2110 - Release Date: 05/12/09 > 06:22:00 -- Paul Kelley, N1BUG http://www.n1bug.com
