Unless you want to spend time with the proper test equipment, it is probably a lot more prudent to make all the cavities in your mini antenna system the same or very similar types.
The stacked T-1500 duplexer layout I describe has the antenna ports joined with another T... while this works fairly well one could probably do better by coupling each of the series cavities into an N-Way ... aka star. You could combine duplexers with n-multiple lengths of coax or hard line but every extra section(s) is loss, bandwidth restrictive and another impedance bump I'd rather do without. Two back to back T-1500 duplexers are pretty much the same layout as the factory supplied Microwave Associates unit at x-times the cost. If you want to be uniform... find another T-1500 off ebay cheap enough. cheers, s. (ps: What's an N-Way... oh about 4 pounds... :-) old bad joke... sorry. > Cort Buffington <[EMAIL PROTECTED]> wrote: > T-1500 type is what's in the commercial repeater (micor). > My repeater > has a Wacom WP-678-R2 on it. > > Odd multiples of 1/4 coax between duplexer tees and the antenna tee? > > BTW: A big thanks to Skipp, Phil and the rest who've jumped in here > today. I sometimes get some crazy notions (ham guy, not commercial 2- > way shop here) and I really appreciate this group. I lurk a lot and > learn a lot -- only hope I can give back more someday. > > 73 DE N0MJS > > On Feb 20, 2008, at 5:08 PM, skipp025 wrote: > > > > > Seen and done this before... > > > > Two Motorola T-1500 type duplexers, one setup on each repeater > > along with the proper tx circulator for each. The antenna port of > > both duplexers joined with another coax T... if you want to be > > really on the money use a n-way and remove the two duplexer > > output T's. > > > > If the reflected power on the antennas is minimal the system > > should play just fine. I've seen it done at more than one commercial > > repeater site. The frequencies are far enough from each other > > that everything should play just fine. > > > > cheers, > > s. > > > > > Cort Buffington <cort@> wrote: > > > > > > Guys, > > > > > > I've found a site for my most recent Ham repeater project. Nice farm > > > tower on a hill, clean of RF colo, etc. The farm repeater is a > > 463.xxx > > > + machine and I'm on 444.825. It is set up with nice hardline and > > a 16 > > > bay folded dipole antenna (not sure the mfg., but he thinks it's > > DB). > > > Anyway, assuming that thing has useable SWR on my TX frequency (I've > > > had that happen before, not holding my breath), does anyone have any > > > ideas about the viability of running both repeaters on the same > > > antenna but connecting the duplexer outputs together in to the > > common > > > feedline? I've done no math, and not a lot of thinking, but is this > > > one of those times when I might run odd multiples of 1/4 wave coax > > to > > > a T at the hardline or something? Both repeaters have BpBr duplexers > > > and both have isolators on their outputs. > > > > > > 73 DE N0MJS > > > > > > -- > > > Cort Buffington > > > H: +1-785-838-3034 > > > M: +1-785-865-7206 > > > > > > > > > > > -- > Cort Buffington > H: +1-785-838-3034 > M: +1-785-865-7206 >
