I heard a similar problem with an ARES net in Oregon. One of the county EOC's had installed a high rooftop antenna for the hams, and could be worked on simplex for many miles, but into the main ARES 2m repeater it sounded as you described, to the point it was unintelligible. It was fine into other repeaters, and the same operator could switch to a simple J-pole or ground plane on a balcony railing and be perfect into the ARES repeater.
My best guess is the antenna, which was on a rooftop bristling with other antennas, was in some unfortunate spacial relationship to other conductors to produce a really disruptive multipath signal on the specific compass heading of the repeater used for the ARES net. The good news: the fix would be simple. The bad news: it would also be a major PITA. You may have to go to that remote site and move something 4 inches to get it to work. 73, Paul, AE4KR ----- Original Message ----- From: John Sehring To: [email protected] Sent: Wednesday, September 02, 2009 12:35 PM Subject: [Repeater-Builder] Repeater trouble Hi all, We have a puzzling problem with our two 2m repeater networks. They all use Mitrek's on 2m and Maxtrac's on UHF for linking; each network has a handful of satellite repeaters, all on diff. 2m freqs of course. All satellites use one of two UHF freqs for simplex linking to their hub repeaters. All it takes to swing a satellite repeater from one network to another is to change the UHF link freq. With the Maxtrac's, that's easy (or should be!). In one instance, we've struggled greatly to do this successfully. After reprogramming the Maxtrac at the repeater site, the UHF linking signal sounds fine on HT's, dual band transceivers & a consumer-grade scanner _at the remote site_. But from the hub repeater, the VHF output signal, coming in from this newly-linked repeater ONLY, sounds garbly, like AC ripple or overdriven PL tone (we don't use PL). At the linked repeater site, we've changed antennas, power supplies & link Maxtrac with no improvement. As our repeater sites are rather remote (in the middle of nowhere, hours driving away from one another, and/or up mountain peaks), we've not had a chance to listen to it at the hub site. So we don't know if the UHF signal is arriving there ok or not, or whether the VHF output signal is somehow being corrupted. The puzzling thing is that A) the newly linked repeater worked perfectly with the 2nd network and B) all satellite repeaters use the same UHF link freq & they all work FB. I wonder what we're missing (duh!)? Any thoughts? Thanks! --John WB0EQ/VE6
