Can't explain it Joe. All I can tell you is that our 7.21 2-Meter Repeater had users in weak signal areas completely wiped out when the community repeater and the fire transmitter came up when they were on 2-meters. As I said we changed the PL's and that is ALL I did and now the same stations talk away and there is NO noise on 2 meters. Also the service tech says it cleared up noise on the fire 154.295 and I can tell you that the community repeater is OK now, the noise that came in on 151.4 does NOT come in on any other CTCSS. Break thru in RF physics, probably just dumb luck, which I am not use to.
JIM -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of MCH Sent: Sunday, August 30, 2009 12:02 PM To: [email protected] Subject: Re: [Repeater-Builder] Nearby Repeaters Again, explain how the mixing products or intermod changed. If that's true, maybe you're really on to something. If I can eliminate intermod by changing the PL tone or the CWID, that would be an incredible breakthrough in RF physics. Joe M. Jim Cicirello wrote: > > > 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 > > > > ------------------------------------ Yahoo! Groups Links
