Frequencies

Definition

In aviation, frequencies refer to the specific radio channels used for communication between aircraft and air traffic services (ATS). These are typically found in the VHF (Very High Frequency) band and are standardized internationally to ensure clarity, compatibility, and safety.

VHF Band Basics

Aviation radio uses the range from 118.000 MHz to 136.975 MHz
Each frequency is spaced in increments of 8.33 kHz
Older aircraft may still use 25 kHz spacing (legacy), but 8.33 kHz spacing is mandatory in most European airspace
Frequencies are always stated to three decimal places, but aircraft radios may only display two

How Frequencies Are Used

Type	Function	Example
Tower	Takeoff, landing, local control	“Wien Tower 118.800”
Ground	Taxi instructions, apron control	“Graz Ground 121.900”
Approach/Departure	Initial climb and sequencing	“Salzburg Approach 124.750”
Radar	Enroute control or vectoring	“Linz Radar 119.275”
Information	FIS, general info in Class G	“Wien Information 124.400”
ATIS	Automated terminal broadcast	“LOWS ATIS 126.030”
Clearance Delivery	IFR route clearance at major airports	“LOWW Delivery 121.730”

Frequency Assignment Principles

One frequency per sector or function to reduce congestion
Ground stations may transfer control by handing over to a new frequency
Pilots must ensure positive two-way contact when switching frequencies

Phraseology Examples

“Contact Wien Radar on one two four decimal four”
“Remain on frequency, report when ready for departure”
“Change to Salzburg Tower one one eight decimal one”
“Monitor ATIS on one two six decimal zero three zero”

Decimal Pronunciation Rules

Always say “decimal” to indicate the point
Correct: “one two four decimal four”
Incorrect: “one twenty-four point four”

Special Frequency Use Cases

Emergency frequency: 121.500 MHz (monitored continuously by ATC and military)
Guard frequency: Also 121.500, used for distress calls and lost comms
Training frequencies: Sometimes allocated for school use, under regulation
Military/UHF: Military often uses separate UHF ranges, not accessible via civilian VHF radios

Tips for Frequency Management

✅ Always confirm a new frequency before switching
✅ Write down unfamiliar frequencies immediately
✅ Listen before transmitting (avoid blocking active transmissions)
✅ Use LearnATC to simulate real-world frequency changes and traffic handoffs