I had exactly this same problem when I used an RCA TAC-200 radio as a repeater. It would let small slivers of squelch COS through to the controller and would key up the tail on the controller. In my case it occurred every 10 or 15 minutes and was an artifact of the radio squelch circuit.
I solved the problem with a CMOS gate circuit. I used a CA4011 and put a 1 meg resistor in series with the input to one of the gate inputs with a cap to ground. The resistor was connected to the other gate input, and as the input COS went positive to both gate inputs, the delay caused by the resistor and cap on one half of the gate would prevent the output from transitioning until the cap charged. A simple circuit and I could draw you a schematic if you need. It completely cured the intermittent keying I had experienced, and I could run the squelch as loose as I wanted and still get reliable operation. In later years I have used the anti-kerchunk capability of the CAT-300 to do the same thing. Setting it to a half second does the trick. 73 - Jim W5ZIT -----Original Message----- From: [EMAIL PROTECTED] To: Repeater-Builder@yahoogroups.com Sent: Tue, 27 Mar 2007 9:29 AM Subject: [Repeater-Builder] AntiKerchunk ?? We have a 440 repeater with a Six meter remote base setup. On the Six meter receiver we constantly get little "pops" that key up the repeater and is quite anoying. The "Pops" are created by very close TV station transmitters at the site and appear to be on channel so filtering is not an option. Our controller does not have a antikerchunker circuit for this second port. I wonder if anyone has a QUICK and SIMPLE circuit for a delayed keying of the conttoller on the COS line? I believe something on the order of 1/4 to 1/2 second would be sufficient in our case. If the receiver COS line keys up, it would not be seen by the controller until the predetermined delay time from this little magic circuit. Anyone out there have any ideas on this????? GARY - W5GNB ________________________________________________________________________ Check Out the new free AIM(R) Mail -- 2 GB of storage and industry-leading spam and email virus protection.
