Poor receiver sensitivity in System Saber III

[kf4sqb]

I have a VHF Systems Saber III with poor RX sensitivity. All the channels are well within the split of the modules in it. Unfortunately, I don't have access to the proper test equipment, so I can't give any specific numbers for the sensitivity, but I do know there is a problem. When a P1225 and a Maxon handheld out-do a Saber, something is definitely wrong . The only way I have to troubleshoot is to make a change, and try the radio out by normal use. So far, I've tried changing the receiver and 5-pole filter module, with no change, and I've now changed the 2-pole filter module, and won't know until later if it helps. I plan to change the FDS if the 2-pole filter doesn't help. Does anyone have any tips for something else to check if none of those three modules take care of the problem? Thanks!

[DJP126]

The only other module in the receiver is the VCO. You have already changed the others. As for components on the main board, I'd look at the crystal filters FL2 & FL3 and I would look at U100 which contains the second mixer and discriminator.

[kf4sqb]

Thanks, Dave, but I think I've already found the problem, and I really, really felt stupid when I did. I had it hooked up to a computer last night making some programming changes anyway, so I decided to check the alignment pages while I was already hooked up. I turns out that a previous owner (the radio used to belong to ATF, if I'm not badly mistaken) had the squelch set to 12! I turned it down to a more reasonable 7, and I'll see how it does today, but I really doubt if I have this particular problem anymore.