Monitoring the Military Part 2: Air Traffic Control

I wrote this article for the February 2007 Key Klix, the newsletter of the Amateur Radio Club of Savannah (ARCS). It is not meant to be an in depth article on Air Traffic Control; it is more of a "beginner's guide" to monitoring military flights through the Savannah, Georgia area.

Air Traffic Control frequencies are good places to start finding military aviation activity; as aircraft are en route from one location to another, they will be in communication with local air traffic controllers or ARTCC air traffic controllers. Typically, these air traffic control frequencies will be in pairs of one VHF (118.000 to 136.000 MHz) frequency and one UHF (225 to 400 MHz) frequency. Both civilian and military aircraft use VHF frequencies; military aircraft use UHF frequencies (AM mode is used on both VHF and UHF). The type of aircraft usually determines whether or not they will use VHF or UHF with air traffic control. Military aircraft will usually have 2 or more radios, a typical combination would be 1 VHF radio and 1 UHF radio (larger aircraft may have more than one of each). Some military aircraft are only equipped with UHF radios (this is becoming less common). For air traffic control, large transport aircraft will usually use VHF; fighter or attack type aircraft will usually use UHF.

Just as amateur radio operators use callsigns, military aircraft do as well.
Military aircraft callsigns are composed of a word or combination of letters followed by a series of 2 or more numbers. For the most part, the word or letter combination identifies the unit or service the aircraft is from and the numbers identify the flight number, mission number, or airframe. For example, ARMY 26260 would be an Army UH-60 Blackhawk; ARMY denotes the service and 26260 is the last 5 digits of the helicopter’s tail number. AB 401 would be a US Navy F/A-18 from VFA-86; AB identifies it as a VFA-86 aircraft and 401 is the aircraft number. SHOOTER 11 would be an F-16 from the 55th Fighter Squadron; SHOOTER is a callsign that the 55th FS uses and 11 denotes the flight number (additional aircraft in the flight would be 12, 13, 14, etc.)

The local air traffic control frequencies are airport tower, airport ground control, clearance delivery, and approach/departure frequencies. The tower controls the airspace immediately surrounding the airport. Ground Control controls the ramp space, taxiways, and runways. Approach/Departure controls the airspace around the airport but outside of the airport’s immediate airspace. In Savannah, although there are two major airports, Savannah/Hilton Head International and Hunter Army Airfield, there is one Approach/Departure facility that handles the area surrounding both. Savannah International and Hunter each have their own tower and ground control facilities. Savannah International also utilizes clearance delivery frequencies to issue departure clearances to aircraft; at Hunter clearances are passed over the ground or tower frequencies.

125.300/387.100 Savannah Approach/Departure
120.400/380.025 Savannah Approach/Departure
118.400/307.225 Savannah Approach/Departure

119.100/257.800 Savannah/Hilton Head IAP Tower
121.900/348.600 Savannah/Hilton Head IAP Ground Control
119.550/291.775 Savannah/Hilton Head IAP Clearance Delivery

133.550/279.575 Hunter AAF Tower
121.800/291.675 Hunter AAF Ground Control


When they aren’t within the areas surrounding the airports, aircraft will be in communication with ARTCC (Air Route Traffic Control Center) controllers. ARTCCs are separated into sectors and altitudes. The sectors are named by a city or airport within the sector (sometimes where the transmitter is located) and by the altitude it covers (low, high, or ultra high). The area surrounding Savannah falls in Jacksonville Center’s area. Sectors surrounding the Savannah area are (once again, both VHF and UHF frequencies use AM mode):

Allendale Low 132.500/363.200
Brunswick Low 126.750/277.400
Jekyll Low 124.675/282.200
Savannah Low 322.500/120.850

Aiken High 127.875/319.200
Summerville High 124.075/351.700
Alma High 135.975/282.300
Statesboro High 126.125/285.650

Hunter Ultra High 132.425/290.350


Related to Air Traffic Control are the Flight Service Stations (FSS). The area around Savannah is under the Macon FSS, which uses 123.650/255.400.
Pilots can contact an FSS to open flight plans, get weather information, etc.

To illustrate how all of this works we’ll create an imaginary flight, ARCS 11, which will depart Hunter Army Airfield and turn south toward Florida. ARCS 11 is given their flight plan via Ground Control on 291.675 and are then given instructions to taxi to the runway. Once they are ready to take off, Ground Control switches them to 279.575 for Hunter Tower where they are cleared onto the runway and then give clearance to take off. When ARCS 11 leaves Hunter’s airspace, they are switched to Savannah Approach/Departure control on 380.025. As ARCS 11 continues south, they leave Savannah’s airspace and are switched to Jacksonville Center on 282.200. At each of these frequency changes, the air traffic controller will pass the new frequency for the flight to switch to. Of course, most of the time you won’t be able to hear the air traffic controller because you are out of range, but the pilots usually repeat the frequency they are given for confirmation, enabling you to follow them along their journey until the aircraft is out of range.


Mac McCormick, KF4LMT
kf4lmt@comcast.net