AM and FM Radio Stations Industry Terminology

AM (Amplitude Modulation)

A radio transmission method in which the strength (amplitude) of the carrier signal is varied to encode audio; in the U.S. the AM band spans roughly 530–1700 kHz and is prone to skywave interference at night but offers long-distance coverage.

We’re reducing our nighttime AM power to comply with our directional pattern.

AQH (Average Quarter-Hour)

The average number of persons listening to a station for at least five minutes during a 15-minute period; used to compute AQH Rating and Share.

Our AQH Persons went up in morning drive.

As-Run Log

The official record of what actually aired (spots, PSAs, IDs, programs) and when; used for billing, affidavits, and FCC/advertiser compliance.

Send the as-run log to traffic for reconciliation.

Automation System

Software/hardware that sequences and plays audio (music, spots, imaging), controls live assist, and interfaces with traffic and ratings encoders.

Schedule the weekend in the automation and set to live assist at 6 a.m.

Avails (Available Inventory)

Units of unsold commercial time within a station’s schedule; a key input to pricing and yield management.

I’ve got two :30 avails in the 7 a.m. hour.

Barter

A deal structure where a station trades commercial time for programming/content rights, goods, or services; common with syndicated shows.

This countdown show runs on a barter basis with four network spots.

Brokered Programming

Blocks of airtime sold to third parties who provide their own content (e.g., financial, religious, ethnic shows), often common on AM.

Sunday mornings are brokered to a real-estate show.

Call Letters (Call Sign)

The FCC-assigned unique identifier for a station (e.g., KXXX, WXXX) that must be announced with the city of license at the top of the hour.

Update the legal ID to reflect our new calls.

City of License

The community to which a station is licensed and for which it must provide legal ID and meet coverage/public interest obligations.

Our legal ID must include the city of license.

Clock (Format Clock)

The minute-by-minute hourly template that defines the sequence of music, spots, imaging, news, and features.

Revise the clock to shorten stopsets.

Contour (Coverage Contour)

Regulatory/engineering lines mapping where a station’s signal meets specified field strength (e.g., 60 dBu for FM); used for interference, market definition, and translator siting.

Our translator must sit within the 60 dBu contour.

CPM (Cost per Thousand)

The cost to deliver 1,000 impressions; common currency for comparing spot radio and digital audio buys.

The CPM on streaming is $12 versus $8 on terrestrial.

CPP (Cost per Point)

The cost to purchase one rating point in a target demo; equals schedule cost divided by GRPs.

CPP in A25–54 is high in morning drive.

Cume (Cumulative Audience)

Unique listeners who tune in at least once during a specified period; a measure of reach rather than intensity.

The contest boosted weekend cume.

Daypart

Standard time blocks used for programming and sales (e.g., AM drive, midday, PM drive, nights, overnights, weekends).

Rates increase in the AM drive daypart.

Delay (Profanity Delay)

A short broadcast delay (often 5–10 seconds) allowing operators to ‘dump’ prohibited content to comply with indecency rules.

Keep the delay armed during call-ins.

Diary (Nielsen Diary)

A recall-based ratings method where listeners log listening in paper/online diaries; used primarily in smaller markets.

Diary returns close Friday.

Directional Array (AM)

An AM antenna system using multiple towers and phasing to shape the signal pattern, protecting other stations and meeting coverage rules.

We switch to the nighttime directional pattern at sunset.

DJ (On-Air Personality)

The presenter/host who delivers music, talk, reads live ads, and engages listeners; also called talent or announcer.

The DJ will voice the live reads.

Drive Time

Peak listening periods during commuting hours—typically 6–10 a.m. (AM drive) and 3–7 p.m. (PM drive)—with premium ad rates.

PM drive is nearly sold out.

EAS (Emergency Alert System)

The national/public alerting system requiring stations to monitor sources and air tests/alerts; includes RWT/RMT and CAP/IPAWS decoding.

Log the monthly EAS test in OPIF.

Equal Time Rule

FCC rule requiring equal opportunities for legally qualified political candidates to use a station, with exemptions for bona fide news events.

That candidate interview is exempt as bona fide news.

ERP (Effective Radiated Power)

The transmitter output power adjusted for line loss and antenna gain; the key measure of FM coverage power in watts/kW.

Our ERP is 50 kW from 300m HAAT.

FCC (Federal Communications Commission)

U.S. regulator overseeing licensing, technical standards, ownership, public files, political rules, and enforcement for radio.

File the license renewal with the FCC.

Flight (Flighting)

A scheduled run of commercials over specific weeks or months, often with on/off patterns to manage budget and impact.

The back-to-school flight runs Aug–Sep.

FM (Frequency Modulation)

A radio transmission method varying the frequency of the carrier; U.S. FM band is 88–108 MHz with higher fidelity and stereo capability.

The FM translator rebroadcasts our AM.

Format (Station Format)

The programming genre and brand strategy (e.g., CHR, AC, Country, News/Talk, Sports); dictates music mix, imaging, and talent style.

We’re flipping format to Hot AC.

Frequency (Assigned Frequency)

The specific carrier assignment for a station (e.g., 93.3 MHz FM or 970 kHz AM) used in branding and licensing.

Promote the new 101.7 frequency.

GRP (Gross Rating Points)

The sum of all rating points delivered by a schedule in a target demo; equals Reach (%) × Frequency.

We promised 150 GRPs in A25–54.

HD Radio (IBOC)

A digital radio technology (In-Band On-Channel) allowing hybrid analog/digital broadcasts and HD2/HD3 multicasts.

Add a sports format on HD2.

Imaging

The station’s sonic branding elements—IDs, sweepers, stagers, jingles—that create a consistent sound and identity.

Cut new imaging for the rebrand.

Legal ID

The required top-of-hour identification consisting of call letters and city of license; slogans may bookend but not interrupt the legal elements.

Run the legal ID at :00 every hour.

Live Read (Host-Read Ad)

Commercial copy read live by the on-air talent, often positioned as an endorsement; valued for authenticity.

The morning host will do the live read.

LMA (Local Marketing Agreement)

A contract where one entity programs/sells another licensee’s station while the licensee retains control; subject to FCC rules.

The LMA includes a shared services deal.

Lowest Unit Rate (LUR)

During political windows (45 days pre-primary, 60 days pre-general), candidates must get the lowest unit charge for the same class/daypart.

Reprice spots to comply with LUR.

Makegood

A replacement spot or units provided when a schedule is preempted or under-delivers ratings/impressions.

Offer two :30 makegoods in PM drive.

Metro Survey Area (MSA)

Nielsen Audio’s defined radio market geography used for ratings and buys; distinct from the broader TSA.

We’re #1 A25–54 in the MSA.

Nielsen Audio

The primary U.S. radio ratings provider (formerly Arbitron) using PPM panels in larger markets and diaries in smaller ones.

Nielsen’s PPM panel updated this month.

Online Public Inspection File (OPIF)

The FCC-hosted online repository where stations must maintain required public files (e.g., EEO, Issues/Programs, political).

Upload the Issues/Programs list to OPIF.

PPM (Portable People Meter)

Electronic ratings system where panelists wear a meter that detects inaudible codes embedded in audio to measure exposure.

Confirm the PPM encoder is synced.

Rate Card

The published (and often negotiable) price list for spot lengths by daypart, sometimes with premiums for position-in-break or sponsorships.

Rate card for AM drive is $150 per :30.

RDS (Radio Data System)

An FM subcarrier standard that transmits data like station ID, song title/artist, and program type to compatible receivers.

Fix the RDS PS and RT fields.

Spot (Commercial Spot)

A discrete commercial unit (commonly :15, :30, :60) sold by daypart and class (e.g., fixed, preemptible).

The buy includes 20 :30 spots in PM drive.

Stopset

A cluster of commercials run back-to-back; number, length, and placement affect listener retention and revenue.

Reduce stopset length to lower tune-out.

STL (Studio-Transmitter Link)

The link (microwave, IP, fiber) carrying program audio from studio to transmitter site; critical to reliability.

The microwave STL dropped in the storm.

Traffic (Commercial Scheduling)

The function/system that schedules commercials, reconciles as-run logs, manages inventory, and generates invoices.

Traffic needs copy by 3 p.m.

Transmitter

The RF equipment that generates and amplifies the broadcast signal; monitored for power, modulation, and compliance.

Transmitter power folded back due to heat.

Translator (FM Translator)

A secondary FM facility that rebroadcasts a primary station on another frequency to extend/fill coverage; often used for AM-on-FM.

Our AM simulcasts on 102.5 via a translator.

TSL (Time Spent Listening)

Average amount of time listeners spend with a station over a period; a depth-of-listening metric that helps drive AQH.

TSL rose after shortening stopsets.

Underwriting

Acknowledgment-style sponsorship messages used by noncommercial stations; must avoid calls to action, prices, and qualitative claims.

Write underwriting copy that’s value-neutral.