I believe our frequency list may be out of date due to the switch to 8.33 kHz channels.
I've been trying to track down a current list as well. Unfortunately the official documents, Irish AIP and IAA websites, only list a few of them, and they still seem to using a mix of 25 and 8.33 frequencies.
Some high altitude (FL250 and above) frequencies confirmed from recent monitoring.
25 KHz
131.150
132.150
135.600
8.33 KHz
122.980 (122.9750 MHz)
134.260 (134.2583 MHz)
135.230 (135.2250 MHz)
They are using more than these but I have not been able to confirm them. Unfortunately most frequency handoffs off the NAT tracks are assigned using CPDLC, same with handoffs within the Shannon airspace, so it makes it hard to track them all down.
As the low altitude sectors are covered well on other radio's is there any chance you could just include the high altitude frequencies on this one to help avoid congestion ?
JS