Good Evening Mike, I'm afraid I agree with Eric,
The problems you are experiencing are not common, when you stated you moved the crystals from the Mark 4 to the spare and are experiencing the same result, was this with the same set of cans? If it was then try two mobiles on the same set of cans and check for desense that way eliminating the Mark 4 and any other Xtal rig you are using. If your desense is still there after the mobile test then you need a tracking generator to go with your spectrum analyser. That will be a start in "seeing" where your problem may lie. Anything more than that may be a return loss bridge and do a resonance check of the entire duplexer. If you do not have the access to the equipment, you can always try a seperate antenna on the opposite port for the duplexer to determine which side, i.e. Rx or Tx is the issue. If you have disassembled the cans and are not having much luck then the Tracking generator should show you where they are tuned and if they are really giving you a problem. By the way, what was your Sinad reading on the Rx of the Mark 4. If you are having more problems with noise than signal you may have found this in your earlier test when you swapped the Xtals and found their amplifier stage may be giving you the grief. If you swapped the Xtal in the element, versus sending it to a crystal house for overhaul, then a cold solder joint makes for all kinds of Rx fun in the form of noise. I am not 100% on the Mark 4, but if it has an Rx alignment procedure, run through that while chasing the Rx board with cold spray or a gentle tap during the test and see if your sinad changes or your performance changes. Your 8920 will show you that in the right range if you have a problem as you look at you Tx signal I hope this can help, Jason --- In Repeater-Builder@yahoogroups.com, "Mike Besemer \(WM4B\)" <[EMAIL PROTECTED]> wrote: > > I spent the weekend working on a set of DB4060 cans (cleaning and retuning) > and have managed to commit the ultimate stupidity. I had all the harnesses > off and instead of MARKING them I just laid them out on the bench. > Unfortunately, the bench got 'cleaned' and the cables are now all mixed up. > > > I can tell which 2 cables went between the cans and which went to the > T-connector, but all 4-cables are different lengths. I assume that the > shorter of the two cables go on the TX (high) side of the cans and the > shorter go on the RX (low) side of the cans. Am I correct? > > Thanks for the help. next time I'll mark the cables! > > 73, > > Mike > WM4B >
