At 11/26/2009 08:30, you wrote: >Ralph you bring up a good point of thought. > >The ham that built our repeater placed the Decibel Products 4002 Bandpass >behind the Wacom 6 can duplexer and then followed by the ARR Gasfed >P144VDG to the radio. > >Now where he built it was his tower site (an old AT&T brick building) full >of transmitters. > >Now that we have it, it is located here at my house in my ham shack. So, >the only transmitters are my 2 meter and HF when I am on HF. The HF >doesn't bother it at all and I run low power on 2 meter when I am on that. > >So, with your thought, I could probably do away with the bandpass all >together run the preamp right out of the cans to the radio (which is a GE >Mastr II mobile).
Yes, but it will offer some protection from your 2 meter radio so you'll desense your repeater a bit less. It also offers some protection from the EMP of nearby lightning strikes: less bandwidth between the strike & preamp means less EMP energy reaching the preamp's input. The DB4002 came with either 0.5, 1 or 3 dB loops. If yours has 3 dB loops, then you'll probably see some improvement in sensitivity by removing the can. If it has 0.5 dB loops, you won't notice a difference. 1 dB is somewhere in between, but if you have any amount of site noise you probably won't notice a difference as well. Here in SoCal you can put a 6 dB pad in front of a preamp & not notice a difference in effective sensitivity. Needless to say, I don't use them on 2 meters here - the stock sensitivity of an MVP or Mastr II is perfectly matched to our environment. I have noticed that away from this area, the noise floor on 2 meters can be much lower. Bob NO6B
