Antenna TV words, in plain English

The number your TV shows, like 2.1. It stays the same even when the station changes frequency.

The number your TV shows, such as 2.1 or 32.4. The part before the dot is the station; the part after is the subchannel. Stations keep the same number even when they move to a different frequency, which is why a rescan fixes most "lost channel" problems.

An extra channel a station sends alongside its main one, like 2.2 or 2.3.

One station can send several channels at once. The main one is usually .1 (for example 5.1 NBC); the others (5.2, 5.3) carry extra networks such as classic TV, movies or news. They come free with the same antenna.

The real broadcast frequency, which can differ from the number your TV shows.

The actual frequency a station transmits on. It often differs from the number on your TV: CBS 2.1 in Chicago does not broadcast on RF 2. It matters for antennas, because the RF channel decides whether you need VHF or UHF reception.

Asking your TV to search for channels again. Fixes most missing channels.

A channel scan (auto-program) makes your TV search every frequency again. Do it whenever a channel disappears: stations move frequency or share signals, and the TV only finds the new location by rescanning.

Our estimate of how easily you get a station: Strong = an indoor antenna is likely enough; Good = attic or outdoor; Fair = roof antenna, aimed; Patchy = reaches only part of the ZIP.

Each station gets a level from our terrain prediction for a typical home in the ZIP. Strong: an indoor antenna is likely enough. Good: use an attic or outdoor antenna. Fair: a roof antenna, aimed at the tower. Patchy: the signal reaches only part of the ZIP, so it depends on your exact spot. VHF channels never count as indoor, because flat indoor antennas are weak there. These are estimates, not yet checked against real channel scans.

Terrain makes this station hard to predict here: it may or may not come in. A channel scan is the real test.

We mark a station "May vary" when hills or the shape of the land put the signal close to the edge of what a TV needs, so small differences (your exact spot, trees, antenna height) decide it. Run a channel scan: it is the real test.

How far the predicted signal is above (+) or below (−) what a TV needs, in decibels. Higher is safer.

In the expert view, the dB number is the margin: how far the predicted signal is above (+) or below (−) the level a digital TV needs. +20 dB or more is comfortable; near 0 is on the edge; negative means a typical setup will not get it. Each +6 dB is twice the signal.

Lower frequencies (RF 2–13). Needs an antenna with longer elements; many flat indoor antennas are weak here.

Very High Frequency: RF channels 2–13. Low VHF (2–6) and high VHF (7–13) need physically larger antenna elements than UHF. Many flat "HD" indoor antennas pick up VHF poorly, so if any of your channels is VHF, choose an antenna that says VHF and UHF.

RF channels 2–6. Needs long antenna elements; most indoor and many compact outdoor antennas are weak here.

Low VHF is RF channels 2 to 6. These frequencies need antenna elements several feet long, so most indoor antennas and many compact outdoor ones barely pick them up. If a channel you want is on low VHF, choose an antenna that lists low-VHF (channels 2–6) support.

Higher frequencies (RF 14–36). Most stations are here; almost any antenna picks it up.

Ultra High Frequency: RF channels 14–36 since the 2020 repack. Most stations use UHF, and almost every TV antenna receives it. UHF signals are more easily blocked by hills and buildings, so aim and height matter.

Transmitter power after the antenna's gain, in kilowatts.

Effective radiated power, in kilowatts: the transmitter power multiplied by the gain of its antenna. Higher ERP reaches farther, but tower height and terrain matter as much.

Smaller stations with a shorter range than full-power ones.

Full-power stations cover a whole market. Class A and low-power (LPTV) stations transmit at lower power and reach a smaller area, often a few towns, but they still carry free channels worth scanning for.

A directional antenna reaches farther in one direction; a wide-beam one covers towers in several directions.

A directional antenna concentrates on one direction and reaches farther, so it suits places where all towers stand together. A wide-beam (multi-directional) antenna covers several directions at the cost of some range.

A motor that turns a directional antenna, so one antenna can aim at towers in different directions.

An antenna rotator turns a roof antenna by remote control. It lets one directional antenna reach towers in different directions, at the cost of re-aiming when you change channel. The alternative is two antennas aimed separately and joined with a combiner.

A small amplifier at the antenna that makes up for signal lost in long cables and splitters. It cannot create a signal that is not there.

A preamplifier sits at the antenna and boosts the signal before it travels down the cable. It helps with long cable runs and splitters to several TVs. It does not help when the antenna itself receives too little signal, and too much amplification near strong towers can make things worse.

A newer broadcast format. Older TVs can't decode it, so stations also send the old format from a partner station.

The newer US broadcast standard (ATSC 3.0). It can carry 4K and better sound, but older TVs need a 3.0 tuner box to see it. Stations that switch to 3.0 keep their channels on the older format (ATSC 1.0) by sharing another station's signal, so a normal TV still finds them after a rescan.

The standard digital TV format every digital TV can receive.

The digital TV standard used since 2009. Every digital TV sold in the US can receive it.

One station switches to NextGen TV and carries other stations' 3.0 versions; partners carry its old-format version.

When a market starts NextGen TV, one station (the "lighthouse") converts its signal to ATSC 3.0 and carries the 3.0 versions of several stations. Its own channels move onto partner stations' older-format signals, so nothing disappears for older TVs. Your TV shows the same numbers after a rescan.