Aviation Sri Lanka
The frequency(s) you monitor will determine the nature of traffic
you will hear. As previously mentioned, frequencies in the lower range
of the aeronautical band are mostly occupied by navigational equipment
and transmit non voice signals in Morse code. If you select a frequency
in the upper range the air is suddenly filled with conversations between
pilots and air traffic controllers, pilots and their company
dispatchers, flight service stations, and ATIS broadcasts. Depending on
your geographical location it is also possible to hear aircraft under
the control of a facility in another Province, or for those living near
the Canadian/USA border an American state. Frequencies within the
aeronautical band are designated according to their usage. The following
frequency allotment chart will give you an idea of where to locate the
traffic that most interests you.
While efforts are made to maintain this arrangement, neighboring
stations may interfere with one another and certain stations may be
assigned a frequency outside of this designation.
There are no rules as to what time of the day is best, however each
airport does have it's own peak periods. Based on traffic patterns at
Pearson International Airport in Toronto, the busiest times occur
between 7 and 9 AM, and 4 to 7 PM. The radio may seem very quiet during
the overnight hours at your local airport this however does not
necessarily mean there is nothing to hear. Monitoring the enroute (ACC)
frequencies can often reward you with traffic from aircraft that have
departed from a distant airport and that are overhead on their way to a
city many miles away.
In order to monitor VHF & UHF aeronautical communications you must have a receiver, more commonly referred to as a scanner, that is capable of tuning between 108.000 to 136.975 MHz and 225.000 to 400.000 MHz respectively. As there are many models to choose from when selecting a receiver the best bet is to first choose one suitable to your budget. Once you are familiar with your new found hobby, purchasing an upgraded radio is an easy transition. Depending on the radio you have purchased the antenna type, if supplied, will vary considerably. This too can be upgraded by purchasing an antenna that performs better for the aeronautical bands. Generally if you live within 40 kilometers of an airport you should be able to hear ground communications, however geographic obstructions such as tall buildings or big hills can hamper your reception. Since VHF & UHF signals are received by line of sight, signals from airborne aircraft tend to be a lot clearer. A good philosophy for optimum antenna performance is "the higher the better". A couple of other useful resources to have while monitoring aeronautical communications would be aviation charts and a base map of your local airfield. With these aeronautical charts you will now be able to plot the course of the aircraft you are hearing. Similarly a base map of your local airfield will allow you to see and follow the route aircraft use between the runways and parking areas.
During radio transmissions letters and numbers can become difficult to understand and may be confused with one another. To avoid any confusion the Phonetic alphabet is use when pronouncing letters. Numbers too are pronounced slightly different thus eliminating any confusion.
UTC or Coordinated Universal Time is used in aeronautical
communications to eliminate confusion between AM and PM. This can be
critical especially to flights that cross many time zones. To calculate
UTC, convert your local time to the 24 hour clock ex; 0100 = 1 AM, 0200
= 2 AM, 1200 = noon, 1300 = 1 PM, then add 4, 5, 6, or 7 hours for
Eastern, Central, Mountain, or Pacific time respectively during daylight
savings time. During standard time add 5, 6, 7, and 8 hours to your
local 24 hour time.
RADIO COMMUNICATION AND NAVI
maps depict the flight routs over the Sri Lanka Flight Information
Region (FIR) where by clicking them you can have larger view of them.