Another thought on the subject, duplexers are rather finicky and even though they have been tuned, unless they are tested on the repeater afterwords, may still not be tuned properly. I went through this earlier this year where a new duplexer was tuned, re-tuned, and made me think it wasn't the issue. I went to my local shop with no idea why I was only able to TX @40w no more than a block when a handheld tx'ed nearly a mile. Even the radio shop tuned and tuned and found several spots where the equipment said it was tuned only to find it wasn't really tuned. After three days, they had the duplexer spot on and the repeater now tx's across town.