Radio Communications

Part 107 requires no radio in your kit, but the exam requires radio literacy: you share airspace with aircraft that talk on frequencies you should recognize, and your closest-call scenarios are usually ones a radio would have revealed. The skills: know the bands, know who owns which frequency, read the ATIS before it matters, and understand enough phraseology to know what that helicopter two miles out just announced.

Do Drone Pilots Need Radios?

Not legally. But operating near airports while monitoring CTAF or tower frequencies transforms you from a surprise into a participant — you hear the helicopter on long final while it’s still a speck. A handheld airband receiver does the job; no license needed to listen.

The Frequency Spectrum (V.A.K5)

Aviation communications live in the VHF airband, 118.0–136.975 MHz — amplitude-modulated, channelized in 25 (or 8.33 kHz internationally) steps. Military users also work UHF (225–400 MHz), with 243.0 MHz as the military guard frequency, paired with civil 121.5 MHz. Your drone’s control link lives far away from all of it, in the unlicensed 2.4 GHz / 5.8 GHz bands shared with Wi-Fi — which is why a crowded marina can cost you control link while an airport never will.

Key Frequencies

Frequency	Use
121.5 MHz	Emergency — international guard frequency, monitored by ATC and airliners
243.0 MHz	Military guard (UHF equivalent)
122.9 MHz (MULTICOM)	Airports with no tower, FSS, or UNICOM — plus temporary, seasonal, emergency, and search-and-rescue activity
122.700 / 122.725 / 122.800 / 122.975	Designated UNICOM frequencies (FCC) for airports without operating towers
122.950	Airports with a tower or FSS on the field
122.750	Air-to-air communication — private fixed-wing aircraft
123.025	Helicopter air-to-air communications; ATC operations
123.050	Airport advisory / FSS at non-towered fields
CTAF	Common Traffic Advisory Frequency — published per airport
Tower frequency	At towered airports — from the chart data block or Chart Supplement

UNICOM (V.A.K4)

UNICOM is a nongovernment air/ground station — essentially the airport’s courtesy phone: fuel orders, advisory requests, ground services. At non-towered fields, UNICOM and CTAF are sometimes the same frequency (e.g., a field with “CTAF/UNICOM 122.8”): the number you self-announce on also reaches the operator who can tell you the winds and runway in use. Strictly, UNICOM provides advisory information; ATC authority it has none.

ATIS (V.A.K5)

The Automatic Terminal Information Service is “the continuous broadcast of recorded noncontrol information in selected high activity terminal areas” (AIM ¶4-1-13) — weather, active runways, notices, all recorded and looped on its own frequency so controllers don’t repeat themselves.

The details worth knowing:

• Broadcast on a discrete VHF frequency (or the voice of a navaid), published in the Chart Supplement
• Each recording gets a phonetic letter code (“Information Bravo”) and updates when conditions change
• Arriving pilots report “with Bravo” — the letter tells the controller which recording you heard
• For drone pilots near a Class D, ATIS is free real-time weather + runway-in-use on one frequency — and it includes that “check density altitude” advisory when the day is hot and high

The Phonetic Alphabet

Aviation’s spelling language, letter by letter:

Letter	Word	Letter	Word
A	Alpha	N	November
B	Bravo	O	Oscar
C	Charlie	P	Papa
D	Delta	Q	Quebec
E	Echo	R	Romeo
F	Foxtrot	S	Sierra
G	Golf	T	Tango
H	Hotel	U	Uniform
I	India	V	Victor
J	Juliet	W	Whiskey
K	Kilo	X	X-ray
L	Lima	Y	Yankee
M	Mike	Z	Zulu

Call Signs (V.A.K6)

Every radio user has one. Manned aircraft use type + registration (“Chandler traffic, Cessna 6132F…”); airliners use company + flight number (“Skywest 4733”). Two rules from AIM ¶4-2-4 worth internalizing:

• Never abbreviate on initial contact — similar-sounding call signs (“Cessna 6132F” vs “Cessna 1622F”) have caused pilots to take each other’s clearances
• If a clearance might belong to someone else, the phrase is “Verify clearance for [complete call sign]”

Drone operations announce with a self-chosen station call sign (“Drone Station Alpha”) — pick something unambiguous and use it identically every transmission.

Standard Phraseology (V.A.K8)

The handful of terms that carry most of aviation radio:

You say	It means
”Roger”	Received your transmission (that’s all)
“Wilco”	Will comply
”Affirmative” / “Negative”	Yes / no — never “yeah” or “nope"
"Standby”	Wait — I’ll call you back
”Say again”	Repeat your last (never “repeat,” which has artillery connotations)
“Unable”	I can’t comply as requested
”Mayday”	Distress — lives in danger
”Pan-Pan”	Urgency — serious, not immediately life-threatening

CTAF announcements follow who-where-what: “Chandler Municipal traffic, Drone Station Alpha, two miles east, will conduct drone photography over the industrial park at 300 feet AGL, Chandler Municipal.” Airport name first and last, position and intention between.

Reading the Traffic, Not Just Talking

Most of your radio value is inbound. A tuned-in drone pilot builds a moving picture from routine calls:

• “Cessna 32 Bravo, entering left downwind runway 22” — aircraft joining the pattern, half a mile out, descending to land. Your drone under the 22 final should already be on the ground or repositioned
• “Cherokee 4470 Sierra, ten miles west, inbound” — a mile a minute of warning, roughly
• “Tower, helicopter 51X requests transition along the river at five hundred” — traffic crossing your area below the pattern; check your own altitude separation
• A sudden cluster of calls = weather or congestion changing; treat radio chatter volume as an activity gauge

The discipline that makes listening pay: silence discipline of your own. Keep transmissions short, plain-language on CTAF, and never step on an aircraft’s position report — the manned traffic’s calls outrank your courtesy announcements.

Light Gun Signals

When radios fail, towers aim a signal lamp at the aircraft (AIM TBL 4-3-1):

Signal	On the ground	In flight
Steady green	Cleared for takeoff	Cleared to land
Flashing green	Cleared for taxi	Return for landing
Steady red	Stop	Give way; continue circling
Flashing red	Taxi clear of runway in use	Airport unsafe — do not land
Flashing white	Return to starting point	Not applicable
Alternating red and green	Exercise extreme caution	Exercise extreme caution

Quick Check

Q: What is the universal emergency frequency? A: 121.5 MHz (civil guard; 243.0 MHz is its military UHF twin).

Q: What’s the difference between CTAF and UNICOM? A: CTAF is the frequency pilots self-announce on at non-towered airports; UNICOM is the airport’s advisory station. They’re often the same frequency, but one is a procedure and the other is a service.

Q: What does ATIS broadcast, and how do you reference it? A: Continuously looped recorded non-control information — weather, runways in use, notices — identified by a phonetic letter (“Information Delta”) that pilots report holding.

Q: What does “wilco” mean? A: Will comply — which also implies you received the instruction.

Q: What does a flashing red light gun signal mean to an aircraft in flight? A: Airport unsafe, do not land.

What’s Next?

Now let’s cover the unexpected: emergency procedures for flyaways, loss of link, and other in-flight emergencies.

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This free course covers the essential knowledge, but if you want video walkthroughs, practice exams, and instructor support, Pilot Institute’s Part 107 course is the most comprehensive option available.