Paul, I've seen the other responses about the Wilkinson divider, but you could also use a UHF receiver with a band-splitter on the antenna side of the duplexer, which could be implemented with as little as a few tenths of a dB loss. You didn't say which VHF band you're on, but a 2M antenna should provide reasonable operation on 430-450 MHz for a control receiver, although the radiation pattern won't be as clean as it might be on 2M.
Even gain antennas usually work reasonably well at odd multiples of their design frequencies, although if you've skimped on coax, loss could be an issue at 430 MHz and above. As for the actual mechanism at the repeater site, I'd recommend using one of the integrated controllers with separate inputs for main and control receivers. Having a separate box with a separate DTMF controller just to defeat the repeater's PTT line creates more failure modes. Also, the integrated controllers will allow modes in which you can kill just the path between the main receiver and the transmitter, and leave the transmitter functional for acknowledgement messages, which can sometimes help a great deal with troubleshooting. 73, Paul, AE4KR ----- Original Message ----- From: Paul - KCØHST To: [email protected] Sent: Saturday, February 16, 2008 9:18 AM Subject: [Repeater-Builder] Remote control systems Where they are used, what is a typical example of a remote control system for a repeater? In other words, to provide the ability to shutdown the repeater remotely, by means other than the input. I think this has been touched on briefly in the past here but I was unable to find anything in the archives. Specifically, what about the receiver antenna connection? We have access to only one feedline connection. If the control receiver is in the same band as the repeater (VHF in this case) could a divider be used off of the duplexer RX port to connect to the remote control RX? Would a cavity be needed also? As for the rest of the system, my inclination would be to use a DTMF decoder output to control the PTT line. Any input is appreciated. 73 Paul - KC0HST
