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Television Antenna Types


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.

Indoor antennas may be sufficient for receiving full power broadcast less than about 20 or 30 miles away, if there is a relatively clear line-of-sight. Attic antennas will have greater range, but there is at least a 3 dB loss compared to outside antennas. Outside antennas work the best, but are more difficult to install and should be properly grounded for best reception and safety (see Installation). A preamp mounted on or close to an indoor or outdoor antenna will extend range in most cases (see Amplifiers).

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ANTENNA BANDS (VHF / UHF)
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
Channels
Frequency
MHz
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
-- TV broadcast Frequency.

RECEPTION COVERAGE
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).

RECEPTION PATTERN
Antenna 3D Plot
RECEPTION AREA
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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ANTENNA GAIN
The larger the antenna, the more signal captured, the more narrow the beam, the greater the reception range, and the greater the antenna gain. 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.
Range vs Antenna Gain

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

Antenna range can roughly be approximated from 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+

INDOOR ANTENNA
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 are powered by 110 Vac (house current) and/or a USB connection. Antenna's that don't use power, don't have a preamp, are considered passive antenna's.

Indoor Antenna Pattern
VHF / UHF
Table Top
Passive
VHF-Hi / UHF
Thin Flat Antenna
Detachable Preamp

OUTDOOR ANTENNA
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

VHF / UHF
High Gain
Passive
VHF-Hi / UHF
High Gain
Amp / 110 Vac
>
UHF
Very High Gain
Passive

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MULTI-DIRECTIONAL ANTENNAS
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.
VHF / UHF
Omin Directional
VHF / UHF
Rotor
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Television Antenna Types
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