Tower Locator Blog

Over-the-Air Digital TV (OTA DTv)

Contents -- Digital vs Analog Broadcast | Digital TV & RF Channels | Watching DTv | Some Station's Changing RF Channels

TV Broadcast Tower One of the first steps to getting free DTv is to find transmitter towers in your area (see Tower Locator). Then with a little planning, and understanding best Reception practices and signal strength Factors, you can get the most stations possible. Antenna selection depends on frequency bands, coverage, and antenna gain (see Reception - Antenna Gain Calculator) needed. Signal loss from cabling depends on cable length(s), signal splitters and connections (see Cables). Outside Antennas should be properly grounded for best reception and safety.

Over-the-Air (OTA) digital television (DTv) requires a stronger signal than analog TV. Additionally, most DTv broadcast are in the UHF frequency band instead of the VHF band. UHF signals are higher in frequency and do not pass through or around objects as well as VHF signals. Also, over-the-air transmission and cable losses are greater at UHF frequencies. Antennas that picked up analog TV signals will also pick up digital TV signals, if the signal is strong enough.

  • Digital TV Requires a Stronger Signal.
  • Most DTv Stations in the UHF Frequency Band.
    • Elevated terrain (Masking) blocks UHF signals.
    • UHF does not bend around large structures as well.
    • UHF dose not go through walls, roofs or objects as well.
  • Analog antenna's will pick up digital TV signals.

A digital television's picture and sound quality are either 100% or nothing. The picture either comes in or it doesn't, depending on signal strength. Digital TV's do have a very small power region (signal strength to TV) the picture pixelates and/or garbles the sound. Analog signals degrade a picture gradually, weaker signals have more noise or snow in the picture.

Cable and satellite operators often compress local broadcast channels before re-broadcasting. The compression reduces picture quality compared to over-the-air broadcast. Compressing signals opens up more bandwidth and allows providers to squeeze in more channels nobody watches.

Analog TV broadcast in the United States ended June 12th (Friday), 2009. Since the introduction of digital TV, the number of over-the-air network channels has dramatically increased.

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TV and RF channels The old analog TV channels were the same as their broadcast Radio Frequency (RF) channel, one network per channel. Digital TV can broadcast multiple channels (in 1 RF channel) and uses 2 types of channels, the TV channel (also called Virtual channel) displayed on the television, and the broadcast RF channel. A stations's TV channel may or may not be the same as it's RF channel. Most analog stations changed their RF channel (and most VHF stations moved to UHF) for DTv, but were allowed to keep their old analog channel identification as their TV or Virtual channel. Stations that signed-on the air after the transition to digital usually have the same TV and RF channel.

Analog Digital Channel
TV Channel
-- virtual channel.
-- displayed on television.
-- multiple sub-channels.
RF Channel
-- Transmission Channel.

Digital Channel numbers are the virtual TV channel, then a dot or dash, then sub-channel number (e.g. 6.3 or 6-3). Television channel 6.3 is virtual TV channel 6, sub-channel 3. The number of sub-channels varies from 1 to 7 or more.

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Broadcast TV requires an indoor or outdoor antenna to receive signals, connected with coax cables to a device for viewing.

Digital Televisions (most) have a built-in Digital Tuner (ATSC standard) for viewing broadcast TV signals.

Computers, Tablets, and Smart Phones require a DTv Tuner to receive TV broadcast. The coax cable from your antenna plugs into the DTv tuner, the tuner connects, usually with an Ethernet cable or WiFi, to your computer or network router / switch. You may need to download a media/TV app for your devices. Some DTv tuners have multiple receivers for receiving multiple TV channels simultaneously.

Analog Televisions (NTSC) require a Digital to Analog Converter Box, sometimes just called a Digital Converter, to receive OTA DTv. Most converters are also recorders. The coax cable from the antenna plugs into the converter box, the box is then connected with another coax cable to the televisions's Antenna Input. Some converters can also connect to the television with video, VGA, HDMI, or YPbPr cable sets for better picture and audio quality.

Digital TV Tuner
Digital to Analog Converters

Some DTv stations will be changing RF channels over a 3+ year period, until about 2020 and probably longer. The FCC, at the direction of Congress in 2012, is re-allocating spectrum, forcing around 1000 TV stations to change RF Broadcast Channels. There are about 8000 TV stations in the U.S. and its' territories. See FCC Spectrum Auction Results, April 2017.

Stations Changing RF Channel
Stations Percent Change
145 1.8% Go off-the-air
13 0.2% Move to VHF-Hi
17 0.2% Move to VHF-Lo
1000(1) 12.5% Change UHF Channel
(1) -- approximate

When a TV Station Changes Broadcast (RF) Channels;

Also see;
Over-the-Air Digital TV (OTA DTv) Contact
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