I am hoping somebody with knowledge of Montreal Centre frequencies surrounding Ottawa could help answer these questions:
1) Does anyone know how frequencies 134.975 and 128.775 are “mapped out”?
(I have determined that frequencies 124.275/135.2 cover areas west and northwest of Ottawa until it reaches Toronto Centre, and 126.575 cover areas north of Ottawa)
2) When aircrafts are going to Ottawa following the “RIVER9 STAR”, are they generally on 128.775 prior to being switched to Ottawa Terminal for Arrivals?
Long explanation for those questions
The reason I am asking is because the CYOW feed contains a Montreal Centre frequency 124.275 (though listed as "Ottawa Terminal"). Over the last few months, I noticed/discovered that around after 10pm ET (though the precise start time varies day-to-day) into the overnight hours, many other Montreal Centre frequencies become available into the feed. As such, I had the opportunity to create a couple of "typical flight" audio clips between Ottawa (CYOW) and Montreal (CYUL).
Recently when I was putting together the audio clip for Air Canada Jazz 8779 from Montreal to Ottawa, I heard Montreal Terminal for Departures handing off the flight to Montreal Centre frequency 128.775 instead of 134.975 - this would have been the first time I actually heard a Controller handing off an aircraft to that frequency.
After creating that audio clip for Jazz 8779, I searched on Flightaware whether there were any other (delayed) flights to Ottawa that would follow the RIVER9 arrival that could be heard on the CYOW feed when they are on 128.775 (as Jazz 8779 followed the RIVER9 STAR into Ottawa from Montreal). As it turned out, I did find a couple of late flights that could be heard when it was on that Montreal Centre frequency before switching to Ottawa Terminal - one on Dec 21/22 and another on Dec 22/23 heard in the CYOW feed. In fact when listening to the archive audio of those flights, they actually checked in with Montreal Centre initially on frequency 132.350 before later switching to 128.775 - conversation on both frequencies from those two flights heard on the CYOW feed.
Now, I have seen frequency 128.775 listed on a Nav Canada Enroute high-altitude charts posted on IVAO.ca, where the frequency could be used in the Ottawa area. But never have I heard Ottawa Terminal for Departures handing off an aircraft to that frequency before going to a destination east of Ottawa. With my lack of knowledge of how the Montreal Centre frequencies are precisely mapped out, I have always had the impression that frequency 134.975 is responsible for areas east of Ottawa, south of Ottawa and within the Canadian border, and west of Montreal. After hearing 128.775 being used, I am a bit confused in the area coverage of this frequency versus 134.975.
I have put together an audio clip containing three Porter flights on both Montreal Centre frequencies that is almost 7 minutes long:
- Porter 287 on Dec 21/22 departing Ottawa to Halifax where Ottawa Terminal does a hand off to Montreal Centre on 134.975, then later asked to switch to the Controller's "other frequency" to 132.350, then a handoff to Boston Center on 128.05;
- Porter 272 on Dec 21/22 from Moncton to Ottawa where the pilot initially checked into Montreal Centre on frequency 132.350 from Boston Center 128.05, then later asked to switch to the Controller's "other frequency" on 128.775, then a handoff to Ottawa Terminal followed by Ottawa Tower; and
- Porter 282 on Dec 22/23 from Halifax to Ottawa - similar scenario to Porter 272, except the handoff from Boston Center was not heard