Batboard

We have two UHF repeaters spaced 1.95MHz apart. I know using two T-1504 duplexers and critical length cables these repeaters can share one antenna. What I am looking for is information on what length the cables between the two duplexers and the new tee should be.

Again, our setup is two independent repeaters complete with their own T-1504 duplexers and isolators. These repeaters are 1.95MHz apart. What we a re looking for is info on the critical length cables that would allow us to use both repeaters on one antenna using a tee connector.

Thanks,

Kevin Berlen

I doubt it will work for you.
But, the manual says for a two branch split, 430 to 470 is TKN6559A cable kit.
Which consists of two jumpers that are 8 3/4 inches of RG-142.
Per the book,You MUST connect the notch loop ( not notch probe ) cavities to the Tees and branch jumpers.
Not sure how you will do that with the duplexers.
(Notch loops are the ones mounted near the cavity top, probes are near the cavity bottom, usually you can see
the copper of the loops thru the adjustment slot, and see the nylon insulator on the notch probes thru the slot)
If it were me, I would use one antenna for RX and one for Tx.
The book states that the min spacing is 2 mhz (which you will be close to), and that the isolation provided will
may be as low as 60 dB.
But, if you are not running the most "sensitive" receivers and you are not running 100 watt
transmitters, it might work.

I am sure this configuration will work. Several years ago we had several sites running in this configuration. The spacing between the pairs must be greater than 500KHz, but less than 2.5MHz for this arrangement to work. These systems have all gone away, and were configured by the old antenna site department at Motorola. We at the shop were never aware of the length of the cables between the duplexers, or how to calculate this dimension. One site in particular that we took care of originally had one repeater installed, and then one day a second one shipped in. We did nothing to the original repeater except install the Motorola supplied critical length cables and tee between the two T-1504's. The systems both worked great, without any loss of coverage on the first one.

I will try the cable length you suggested and see how things work out. I do remember that the cables were RG-142, so the 8 3/4 length is probably correct.

Thanks,

Kevin Berlen