Here in Utah, our amateur repeaters share sites with commercial and the broadcasters repeaters. We chose the Low in/Hi out plan on UHF so that our amateur repeaters could co-exist with them at our mountain top sites and not get de-sensed with the numerous 450.xxx broadcasters and 451.xxx commercial repeaters.
We could not see having our amateur repeater receivers at 449.xxx being so close to the 100 watt 450.xxx and 451.xxx repeater transmitters. To avoid intermod that can be generated at the site, we install dual isolators to get around 70 db of isolation on our transmitters and we use band pass type cavities and or BpBr duplexers on every repeater. Some locations have transmitter combiners that use dual isolators on each port. Everyone cooperates and keeps their sites clean and removes unused antennas and hardware from their towers. This has proven to be sound engineering practice for our repeaters. These repeaters are located at Farnsworth Peak which is 18 miles west of Salt Lake City where it is classified as the 3rd most RF populated site in the USA! All of the local NTSC, DTV, FM Broadcast and most all Two Way repeater systems are located here. I also own and operate several VHF and UHF repeaters. John Lloyd, K7JL Utah VHF Society Frequency Coordinator Posted by: "k7pfj" [EMAIL PROTECTED] k7pfj Date: Sun Feb 25, 2007 7:52 am ((PST)) Being the chairman on a repeater cordination councel and having many operational UHF repeaters. One could only wish that the band plans were the same as in the country but everyone has to be a little bit differant. We the hams dictate what we want to do and if we all in the country could decide on a band plan that is standard it would make cordination a little more pleasant to deal with. Cal guys on the middle sound like they are getting screwed. Here in Oregon we are Low out and high in. Well thats nice but when you are offered to combine into a site combining system things have to be done to accomidate the low freqs. It we were all low in and high out it would, one help all of us in the since you would get your recievers away from the 450 stuff and keep the trasmitters all together. You would most likley notice that your repeaters would recieve better. More than half of my repeaters run through combining and when were building the combining we make provisions for hams to have some slots so we can have everthing on the site run through the site antennas. How about a 5 channel ham VHF combiner with all repeaters operational and work great. 73 K7PFJ ____________________________________________________________________________________ Want to start your own business? Learn how on Yahoo! Small Business. http://smallbusiness.yahoo.com/r-index
