Don't leave out the isolated TEE between the duplexer and dummy load, Ron. Hi, Steve NU5D
Ron Wright wrote: > Bill, > > In finding desense first one must locate the problem. A given. > > I would start with putting GOOD dummy load on the duplexer output and do a > desense test. This can be done with a local signal gen where you can vary > the gen output and keying and unkey the transmitter. You should see no > difference in the received signal with tx keyed or unkeyed. > > If you do then the desense is in the repeater. Next do the same test with > the dummy load on the transmtter only. This will test for the desense being > inside or outside the radio part of the repeater. > > I would look at your LMR400 and antenna. I think the LMR400 is a double > shielded cable with different metals for the 2 shields. This is a no no in > duplexed system. It generates noise. It has been discussed here on this > board many many times and for good reason. If this is a problem replace with > a good heliax. It is worth the cost. > > This is a start. > > 73, ron, n9ee/r > > > >
