That's why the big birds have all that TSO stuff, ADSB, and other majik IFF and avoidance stuff. Maybe some of the area frequencies could be decoupled and/or have more boundaries. 124.55 and the other metro areas probably have too big an area. Out beyond the sandstone curtain area frequencies are very quiet. Actually 124.55 isn't too bad. YSBK is worse, especially when arrival, departures and circuits all get coupled together even though they are on different frequencies. I don't listen into the Mascot transmissions so I don't know how busy that gets.