We've successfully used the S-COM variant of this for years, here. anti-kerchunk set up correctly, works fine. (That is, it's NOT active until the repeater has been IN-active for quite a while.)
The reality though is that it just trains the kerchunkers to do longer kerchunks. The problem doesn't really go away, but at least you know it's a valid signal (with CTCSS decode on at the repeater site), and it gives you a longer transmission to DF, if you're really interested and care. most of the time, no one does. Mixing the activation of the anti-kerchunk with a voice ID from the repeater at least gives the kerchunkers something to listen to, since the majority of them are licensed hams looking to see if they can "hear the repeater". This seems to minimize CONTINUOUS kerchunking. they do it once, get a very long voice ID back, and they're "satisfied". Some people are just morons who can't be bothered to take a moment to say their callsign once or even more politely, saying their callsign and "testing", instead of just kerchunking illegally. You can't fix stupid. All you can do is set up your repeater controller to make being stupid, really annoying for the stupid guy. As someone else pointed out, if you build the repeater to act more like a commercial system with CTCSS only transmitted on real user input, no one hears the transmitter "tail" and kerchunks are really boring for anyone running CTCSS decode. you hear a click, and that's it. Kerchunkers are just a part of life when you run repeaters, basically. Nate From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Paul Plack Sent: Sunday, March 15, 2009 11:16 PM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Repeater Kerchunk The duration-based "anti-kerchunk" filters are way more obnoxious than the kerchunkers IMHO, and they also block legitimate users who make quick calls. 73, Paul, AE4KR