Bill’s Nova Scotia Radio Site

Bill’s Map of Atlantic Canada Area ACC High Level Coverage Zones, showing Frequencies,
with Accompanying Notes

Last updated August 18, 2015

Moncton Centre boundaries in the northern extremes are not yet fully determined by myself and are therefore subject to change when more definitive information is received.

Grouped frequencies may be used interchangeably within the general area of coverage, with one, some or all in actual use at any particular time. Frequencies are placed on the map according to normal general area of usage, with a pointer to the actual ground transmitter/receiver location, as follows:
TM = Thetford Mines (St Andre d'Irlande), Mt = Millinocket, A = Augusta, B = Bucks Hbr, Y = Yarmouth, H = Halifax, S = Sydney, M = Moncton,
Gr = Grindstone (Cap aux Meules), SI = Sept Iles, N = Natashquan, SA = St. Anthony, St = Stephenville, G = Gander, T = Trepassey

Notes to Accompany Marscan’s Map of
 Atlantic Canada High Level Control Areas

This map depicts the high level control area for Moncton ACC (“Moncton Centre”) and as well parts of surrounding Canadian ACC’s and for Boston ARTCC.   It is intended for my personal use as an aircraft radio listener located near Halifax, NS and therefore focuses on Moncton Centre but you may also find it useful.  These notes are for you and assume you know something already, but not necessarily all the details.  Those of you who already know a lot may find this simplistic but I think it succinctly shows the radio listening situation, and is useful as well to use in conjunction with on-line flight-tracker websites.   Not all frequencies shown, even for Moncton, can be directly received at Halifax, but might be received indirectly via cross-coupling or by internet feed services.

Note that the frequencies shown are VHF only.  In some areas there may be parallel UHF frequencies for military aircraft to communicate with civilian controllers, but it does appear that these are no longer in any significant use.    Note also that in the oceanic areas, HF radio is used and a suite of HF SSB frequencies are assigned and available for use.  Listening to aircraft beyond VHF and radar range is outside the scope of this map and explanation.  Note however that Gander Oceanic does have some VHF clearance delivery frequencies and sites, such as 119.425 at Sydney, NS, and that New York might be heard on 129.9 via various locations.  Gander Oceanic is operated by Nav Canada just like the Canadian ACC’s and might be referred to as Gander Radio.   New York is operated by ARINC and might be referred to as New York ARINC or as New York Radio.

The base chart used is FAA North Atlantic Route Planning Chart (NARC) current in June 2015, and downloadable from the FAA website.    The area shown is a small part of the total chart which covers all of the North Atlantic Ocean and adjacent coastal areas.  Note that this chart clearly shows the current ocean entry points that are commonly referred to on-air by east-bound aircraft, such as SUPRY and JOOPY.

The red lines depict the control area boundaries, and differ from those for the low level control areas, not shown here.  

Behind the scenes, ACC/ARTCC control areas are divided into many sectors, which can be stand-alone or combined with other sectors to meet traffic needs.  Generally speaking these sectors and their boundaries are of little direct interest to radio listeners, as it is the radio frequencies that matter.   While in theory there could be a specific frequency for a particular sector, it does appear that in most cases a frequency can be used in more than one sector, and varying over time, in a dynamic model of utilization.  Due to the changes in specific frequency use from day to day, it does seem to be of no benefit to even attempt to depict sectors on this map.

Frequencies shown are those known to be in use in the general areas in which they are placed, and there can be some overlap with adjacent frequency areas.  Some frequencies are in more nearly constant use, whereas others are used only when traffic volume requires them.  

Note that the controllers working any of the depicted frequencies are physically located at the ACC/ARTCC location, but the ground transmitter/receivers are generally located far afield, and remotely operated.   The ACC/ARTCC central locations are as follows:   Moncton ACC is at Riverview, NB.    Boston ARTCC is at Nashua, NH.   Montreal ACC is at Pierre Trudeau International Airport in Montreal.  Gander ACC is at Gander Airport in Newfoundland.  The remote stations are referred to as PAL’s in Canada and RCAG’s in the USA.  Each of them will have a transmitter site and a receiver site, located apart from each other to prevent overloading of the receiver by the transmitter. This edition of the map does not show the ground location of the PAL’s but a future edition might do so if it is useful and practical.   

Listeners can expect to directly hear high level aircraft as far away as 200 nautical miles or more, depending on receiver quality, receiving antenna, aircraft altitude, and aircraft antenna selected.    The ground stations will be heard on the ground by hobbyist listeners only out as far as approximately 30 miles, which is likely an extreme range, and again depends on the receiver sensitivity, location and antenna.

The pink line dividing the Moncton area separates the West zone from the East zone.  Within each of the two individual zones it is common for various sectors and their frequencies to be combined.  It appears that combination does not occur across the pink line.   Similar situations might be in effect in the other ACC areas but I have no specific knowledge of these and have therefore divided only the Moncton area.

The first level of combination is for one controller to have more than one sector and therefore more than one frequency to monitor.  In this case he or she will listen on all the frequencies for the combined areas.  When an aircraft calls on one of the frequencies, the controller will transmit the reply on all of the frequencies. For the purposes of this article, this will be referred to as “simulcasting”.  This is not an official term. A listener fortunate enough to be able to hear one of the connected ground stations will hear transmissions from the controller to several sectors, but will hear the replying aircraft only on its specific frequency, by scanning, and if in range of the aircraft.   The second level of combination is for the above to occur but with the addition of cross-coupling in which the aircraft transmission on one of the combined frequencies will be received by the controller and then retransmitted on all the other combined frequencies.   A listener able to hear one of the connected ground stations will therefore be able to hear both the controller and the aircraft on all of the cross-coupled frequencies.  

My specific situation that can be used as an example:

I am fortunate to be in reception range of the Moncton PAL near Halifax Airport on 133.95.   This frequency is almost always simulcast with 125.25, which is the primary frequency for the offshore area extending south and southeast from the northeast mainland of Nova Scotia and Cape Breton Island.  (If 133.3 and/or 133.7 are also in use in that area, the simulcast will include them but I will just use 125.25 in this example). The PAL for 125.25 is located at Sydney.   In this simulcast, I can regularly listen on 133.95 and hear transmissions TO aircraft that are on both 133.95 and 125.25.  Because I am listening on 133.95 I will hear aircraft transmissions on that frequency only, except that I will also scan and will hear the 125.25 aircraft transmissions direct from the aircraft, if they are in range.  When far to the east, nearing the Gander boundary I will most likely not hear them but otherwise I can.  Thus I can hear both sides of the 125.25 exchanges even though I cannot actually hear the 125.25 ground station.     Sometimes the simulcasting will take in additional frequencies, maybe ALL of the active frequencies in the East area, and the same situation applies.    If the simulcasting involves frequencies from the far north of the Moncton area, I will not hear the aircraft side at all.    

If the 133.95 station near me is cross-coupled, as it sometimes is [beginning in the summer of 2015] the simulcasting is augmented by a complete retransmission of all connected frequencies, and I can hear both sides of the conversations.  If the cross-coupling is of ALL the East frequencies I will hear everything through the 133.95 PAL, even from aircraft in the far away areas such as north of the Gulf of St. Lawrence.  

An oddity in my situation is that I live within the Moncton West area, but it is the Moncton East area I hear best, because the Halifax PAL serves the East area, despite being physically located in the West area like me. 

Note that it appears that neither level of connection ever crosses over the pink line on the map so I do not have this luxury when it comes to areas outside the Moncton East area.  The East and West areas appear to be operated completely separately.   It is possible that the same two levels of connection might also be happening in the West area but I am not in range of any ground station from that area and can neither confirm nor deny that it happens.    For that area, and for any Boston, Montreal or Gander communications that I hear, I am only hearing the aircraft side of the conversations, and always directly from the aircraft.   If I do want to hear the controller side, I can go on-line to LiveATC.net and pick up the Boston controllers who are on the frequencies shown.   Currently it does not seem to me that the Moncton West area, Gander or Montreal frequencies shown are available on-line.