Blog
OTA DTv

Steps to Getting
Over-the-Air Digital TV

RECEPTION FACTORS
Signal Path

Basic steps using Standard Practices for getting over-the-air television, and the most channels.

Compass
1 - Find Broadcast Towers

Use the TV Broadcast Tower Locator to find;

Broadcast Towers Tower
Angle to Towers -- for pointing antenna.
Frequency Bands -- for selecting an antenna,
VHF and/or UHF Band(s).
Signal Path -- check for a relatively
clear path to tower.
Signal Strength -- available to Antenna.
for estimating Signal to TV


antenna
2 - Home Antenna

An indoor antenna should work when TV towers are located less than about 20 or 25 miles. A larger outside high gain antenna is needed for ranges up to maybe 40 miles. A much larger outside very high gain antenna is needed for greater ranges. The larger the antenna, the more signal captured, and the higher the antenna the greater the signal density.

ANTENNA PLACEMENT
POSITION -- As High as Possible.
-- Clear Path to Towers.
LOCATION
Outdoor -- Avoid Overhead Utility Lines.
Indoor -- Works best on/near a window.
Attic -- Metal backed insulation,
air ducts and vents,
block signals.

Frequency Band
Television signals are broadcast in either the VHF or UHF frequency bands. Most broadcast are in the UHF band, and virtually all home antennas receive UHF signals. The VHF band is sometimes divided into VHF-Lo or VHF-Hi.

Gain and Reception Beam (Beamwidth)
The larger the antenna the higher the gain, and the more narrow the reception beam.

Gain and Beamwidth
ANTENNA Gain
dBi
Beamwidth
Degrees ( ° )
Low Gain (Indoor) 2 - 4 ≤ 120°
High Gain 5 - 10 45° - 70°
Very High Gain 11 - 18+ 20° - 30°

3 - Signal Loss

Over-the-Air Loss
Ground clutter such as trees, foliage, hills, and structures can reduce or block signal reception. Antennas less than 30 feet above ground level (AGL) will have an antenna height loss. The lower the antenna the greater the signal loss.


See;
-- TV Antennas.
-- Installation.
-- Terrain Loss.
-- Clutter Loss.
-- Antenna Height Loss.
-- Indoor Antenna Loss

Cabling Loss
Cable length and signal splitters account for the most loss. Connectors, adapters, and higher frequency signals add some loss. There's enough difference between VHF and UHF signals they should be accounted for separately. See below calculator.

Coax
Cable Loss Factors
  • Cable Length.
  • Signal Splitters.
  • Connectors and Adapters.
  • RF Channel ((Signal Frequency).

RG-6 coax cable is the industry standard for connecting an antenna to televisions. Also see TV Coax Cables and Signal Loss.

Sponsored links


4 - Calculate Signal to Television
Test Pattern

Television receivers require a minimum signal level greater than ≈ -65 dBm, but it can be as low as -75 dBm to as high as -50 dBm. Signal strength calculation is an estimate and can vary widely with situation.

See -- TV Minimum Signal.
-- Signal Factors.
-- Amplifiers.
TV SIGNAL RECEPTION
Signal to Antenna dBm
+ Antenna Gain dBi
- Antenna Height Loss dB
- Clutter Losses dB
- Cabling Loss dB
= Signal to TV dBm


Estimate Signal to Television
RF Channel:
Signal to Antenna: dBm
Antenna Gain:
Antenna Height:
Area
Clutter Loss: dB
Coax Cable Type:
Cable Length:
Signal Splitters: 2 Ports , 3 Ports
4 Ports , 8 Ports
Connectors: Ground Block, barrels etc.
Twin-lead/Coax Adapters

RF Channel
Frequency / Band

Antenna Gain
- Antenna Height Loss
-Clutter Loss
-Cable Loss
-Splitters Loss
-Connectors loss

= System Gain / Loss
+ Signal to Antenna

= TV SIGNAL
Strength Bars



Sponsored links

Summary

The ideal scenario is an antenna 30 feet or more above the ground, pointed directly at the tower antenna, with flat clear open terrain and a clear line-of-sight.

BASIC STEPS
1.) Find TV Broadcast Towers.
Angle, UHF or VHF, Reception Signal,
Estimate Radio Horizon range.
Tower
2.) Determine Home ANTENNA;
a.) Placement,
b.) Type (Gain, VHF/UHF, Size).
c.) Grounding Method.
antenna
3.) Estimate SYSTEM LOSSES.
a.) Cable / Splitter Loss.
b.) Ground Clutter Loss.
c.) Antenna Height Ground Loss.
Coax
4.) Calculate Signal To TV (below). 4 Bars

Standard Practices

ANTENNA
Placement
  • As high as possible.
  • Clear of clutter in tower directions.
  • Pointed in direction of broadcast towers.
Frequency
Bands
  • Most broadcast are in the UHF band.
    In some cases a UHF antenna works for VHF signals.
  • Use a VHF / UHF antenna to get all bands.
Weak
Signals
  • Use a high gain antenna.
  • Install an antenna pre-amp.
Distant and
Spread Out
Headings
  • Use 2 or 3 antennas.
  • Use an Omni antenna (360° coverage).
  • Rotor antenna (high gain and 360°).
CABLING
Coax
  • RG-6 coax cable (F-type connectors).
    Can use RG-11 or RG-59 coax cable.
  • Cable runs as short as possible.
  • Use quad shield coax for outside runs.
Connectors
  • Make sure all connectors are tight.
  • Check outside connectors for corrosion.
  • Outside connectors covered with a
    rubber weather boot or electrical tape.
  • Unused ports capped with a 75 Ω load.
Long Cable Runs
  • Use a Booster amp.
Multiple Splitters
  • Use a Distribution amp.

OTA DTv
Steps to Getting OTA DTv