I can tell you that the same tones on different frequencies inside the same site can cause a problem. My 2-meter repeater was on 151.4, the same tone as the local high band fire and channel on the VHF community repeater. When a combination of the units with 151.4 came up, I had inter-mod on my 2-meter machine. Also at times there was noise on the fire that we could tell disappeared when the 2-meter dropped along with the community repeater. Luckily I own the tower so I was able to move my 2-meter repeater to 123.0 and it happened that my private channel on the community repeater was also 151.4 which I also changed. Now I try to make sure that every PL inside my site is different. Since there is NO two PL's the same, the problem went away. Our Motorola Tech told me this is common at tower sites using the same PL on different frequencies.
73 JIM From: [email protected] [mailto:[email protected]] On Behalf Of WA3GIN Sent: Sunday, August 30, 2009 9:07 AM To: [email protected] Subject: [Repeater-Builder] Nearby Repeaters Looking for opinions. Our club has a couple of 2m repeaters; we chose to run them with PL and we picked 107.2 because that tone freq. was not in use in the area. Recently two other clubs who also have 2m repeaters have decided to utilze the same PL tone freq. Does having numerous repeaters PL'd with the same tone freq. increase the probability of the normally generated intermod/mixed signal to now carry within the produced signal a correct PL tone that may land on the input freq. of another local repeater? Is it considered a bad practice to utilize the same PL for numerous repeaters in the same band all located within a few miles of each other? Thanks, dave wa3gin
