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TV Antenna Options


Contents -- Indoor Antenna's | Outdoor Antenna's | Multi-Directional | Bands | Reception Area | Gain

As a general rule, the larger the antenna the more signal captured and;
- the greater the range,
- the more narrow the beam (reception angles).

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INDOOR ANTENNAs

There are 3 basic types of indoor antenna's;

Indoor Antenna Pattern
Stick Antenna
  • mounts directly to TV.
  • mostly out of sight.
  • 10 - 15 mile range.
Indoor Antennas
Table Top Antenna
  • place on a flat surface.
  • easy to change angle.
  • 15 - 20 mile range.
Indoor Antennas
Thin Flat Antenna
  • table top, wall,
    or window mount.
  • 20 - 25 mile range.
Indoor Antennas

Gain varies from about 2 to 4 dBi without a preamp (passive antenna). A preamp can greatly extend range in most circumstances. Many indoor antenna's have a detachable preamp. Preamp's are powered by 110 Vac (house current) and/or a USB connection. Also see Amplifiers.

VHF / UHF
Table Top
Passive
VHF / UHF
Thin Flat Antenna
Detachable Preamp
VHF / UHF
Table Top
Built-in Preamp

OUTDOOR ANTENNAs

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
Moderate Gain Antenna Pattern


Very High Gain Antenna
  • mount outside.
  • too large for most attics.
  • less coverage.
  • 11 to 15+ dBi
  • 50 - 85+ miles
High Gain Antenna Pattern


UHF
Very High Gain
Passive
VHF / UHF
High Gain
Passive

VHF-Hi / UHF
High Gain
Amp / 110 Vac

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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.
    • 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
FREQUENCY 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. Television antenna's are available in 4 common configurations.

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

Also see TV broadcast Frequency.


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RECEPTION AREA

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.

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.

Omni directional antenna's receive signals equally from all directions, but require a built-in preamp (and power source).

GAIN (dBi & dBD )

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

Convert to dBi or dBD

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
Gain +dBi Miles
Low / Moderate 2 to 4 20 to 30
High Gain 5 to 10 30 to 50
Very High Gain 11 to 15 50 to 85+

Also see Antenna Gain Calculator.

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