Tower Locator Blog


TV Antenna's

Contents -- Bands | Coverage & Gain | Indoor Antenna's | Outdoor Antenna's | Multi-Directional

There is no difference between a digital antenna and an analog antenna, except the name. Digital and analog TV signals both use the same carrier frequencies, carrier modulation (digital or analog signal) does not effect antenna reception.

A preamp mounted on or close to an indoor or outdoor antenna will extend range in most cases (see Amplifiers).

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Television antennas are designed to receive up to 3 frequency bands; VHF-Lo, VHF-Hi, and UHF. Most TV stations are in the UHF band, and most areas have at least one VHF station. Home antenna's are available in 4 common configurations.

Frequency Band
Band RF
VHF-Lo 2 - 6 54 - 88
VHF-Hi 7 - 13 174 - 216
UHF 14 - 69 470 - 806
Antenna RF Channels Frequency
VHF RF 2 - 13 54-216 MHz
UHF none none RF 14 - 69 470-806 MHz
VHF-Hi / UHF RF 7 - 69 174-216 MHz
470-806 MHz
VHF / UHF RF 2 - 69 54-216 MHz
470-806 MHz

Antenna size is proportional to wavelength. A UHF antenna is smaller than a VHF antenna because UHF wavelengths are shorter. Signals in the UHF band have quarter wavelengths that vary from 2 to 4 inches, VHF varies from 1 to 4 feet. Antenna's that receive VHF and UHF are actually 2 antennas built into each other. The smaller UHF elements are built around or outside the larger VHF elements.

Also see Wavelength Calculator, and TV broadcast Frequency.


Most antenna's are directional and must be pointed in the broadcast tower direction for best reception. Antenna's can pickup signals from all directions, but signals not in the main beam are greatly reduced. Omni directional antenna's receive signals equally from all directions, but usually require a built-in preamp (and power).

Antenna 3D Plot
antenna coverage

Antenna beam width varies from less than 30° for a high gain antenna, to 120° for some indoor antenna. At the beam edge gain is down by - 3 dB, and drops rapidly past the edge. Also see Reception Factors / Beam Loss.

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The larger the antenna;

Antenna gain is measured in dBi or dBD. Manufacturer's use a standard dipole antenna to measure gain in dBD. The dBi unit is used for calculations. Be suspicious of antenna gain expressed in "dB", this can mean anything.

dBi = dBD + 2.15
dBD = dBi - 2.15
dBi - decibels (dB's) compared to a lossless isotropic radiator.
dBD - dB's compared to a standard half wave dipole antenna with a gain of +2.15 dBi.

Antenna range can roughly be approximated from gain.

Range vs Antenna Gain
Antenna Gain +dBi Miles
Indoor Low / Moderate 2 to 4 20 to 30
Attic / Outdoor High Gain 5 to 10 30 to 50
Outdoor Very High Gain 11 to 15 50 to 85+

Also see Reception / Antenna Gain Calculator to estimate gain needed.


There are 3 basic types of indoor antenna's;

Indoor Antennas
Stick Antenna
  • mounts directly to TV.
  • mostly out of sight.
  • 15 - 20 miles.
Table Top Antenna
  • easy to place.
  • easy to change angle.
  • 20 - 25 miles.
Thin Flat Antenna
  • table mount, wall, or window.
  • easy to place for best reception.
  • 25 - 30 miles.

Gain varies from about 2 to 4 dBi without a preamp. A preamp can greatly extend range in many circumstances. Many indoor antenna's have a detachable preamp. Preamp's are powered by 110 Vac (house current) and/or a USB connection. Antenna's that don't have a preamp, don't use power, and are considered passive antenna's.

Indoor Antenna Pattern
Table Top
Thin Flat Antenna
Detachable Preamp


An Outdoor High Gain antenna is usually required for tower distances greater than 25 or 30 miles. Most high gain antennas are sized to fit in most attics. A Very High Gain antenna is usaually required for ranges greater than 50 or 60 miles. These antenna's are usually too large to fit in most attics and must be mounted outside.

High Gain Antenna
  • can mount outside.
  • sized to fit in most attics.
  • good coverage.
  • 5 to 10 dBi.
  • 30 to 50 miles
Very High Gain Antenna
  • mount outside.
  • too large for most attics.
  • less coverage.
  • 11 to 15+ dBi
  • 50 - 85+ miles

Moderate Gain Antenna Pattern High Gain Antenna Pattern

High Gain
High Gain
Amp / 110 Vac
Very High Gain



A multi directional antenna system is required for distant and spread out broadcast headings. Most of these systems require 110 Vac power (house current) to run a preamp and/or rotor. A rotor system has the advantage of good gain and full 360° coverage. A high gain antenna with a built-in preamp mounted on a rotor has the highest performance.
  • multiple antennas
  • omni directional (360°) antenna
    • relatively small.
    • usually require a preamp.
    • well suited for marine or RV use.
  • rotor antenna
    • 360° coverage
    • takes time to change angles.
    • Highest performance.
Omin Directional
Top Over-the-Air Digital TV (OTA DTv)
Television Antenna Types
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