Using CTCSS or DCS to filter traffic

[VK4ADC]

The telling info " I've just learned that the Mt.Alexander repeater VK3RCV needs no CTCSS after all. I had been working from obsolete documentation. I don't know when it was changed. In that case I can include a tone in my transmissions and set my transceiver to ENC/DEC, i.e. to require the same code to pass received signals to the audio. As long as I keep an eye on the radio's display to ensure I don't barge into a conversatiton my brother and I can use the frequency in silence. "

The fact that the repeater is straight carrier-operated makes it possible to do either CTCSS or DCS, but you may need to pick a high CTCSS tone to make sure it transits the repeater without severe attenuation. Some commercial repeaters have a highpass audio filter to chop out frequencies below about 300Hz to stop control CTCSS tones going through, and depend on re-generation from a CTCSS encoder for outgoing tones - when required. The choice of a high tone should solve that one, if applicable.
I haven't tried DCS through a repeater but it might work for you. Try both options.

When you have it solved, make sure you re-post here so that others can benefit from your findings.

73 Doug