I am going to ask a question that might sound stupid but, based upon Icom's ignorance, I need to ask. Did you ever open the repeater case on the 2m repeater and replace the rg-58 patch cables that are zip tied to each other to connect the rf modules to the rear of the case before adding your preamp? Our local repeater guys had serious desense and ended up replacing the junk cables with rg393.........And you may find that the receiver sensitivity is closer to 0.6 uV. IF you insist on using the preamp, I would suggest using a decade box to attenuate after the preamp.....changing the attenuation periodically to get it to a better level. +18dB is a little too much for any receiver.
Jason, WA1NH --- In Repeater-Builder@yahoogroups.com, "atms169" <atms...@...> wrote: > > Yeah that is a good question. All we do is test from a portable a few miles > from the repeater. Low power settings on TX for the portable. > > Test with the amp inline and the amp out of the equation. I find very > quickly there is something wrong. > > That's all I can do, I can't vary the output power. I can also test by just > dropping the 25 watts to 5 watts on the repeater when a user is on the fringe > of the system. If he starts to garble with his audio, I can drop the switch > to 5 watts and bang, he's made it in the system clear as a bell. If I throw > the switch back to 25 watts, he garbles again. > > > > --- In Repeater-Builder@yahoogroups.com, Joe <k1ike_mail@> wrote: > > > > This leads me to a question that I have had on my mind. How are people > > doing desense testing with D-Star systems? (Remember, it's digital.) > > > > 73, Joe, K1ike > > > > Eric Lemmon wrote: > > > Aaron, > > > > > > My CommShop for Windows program suggests that about 88 dB of isolation is > > > needed for a 20 watt repeater, assuming 0.2 uV sensitivity on the > > > receiver- > > > which you didn't specify. > > >
