a.k.a. Over The Air TV
TV Stations broadcast the content / programs over air as well as making them available via Cable, e.g. Comcast, Optimum, Verizon etc. Each TV Channel is assigned a range of frequencies to use for their broadcasts by the Federal Communications Commission (FCC). These broadcast radio frequencies (RF) fall into 3 groups or bands as illustrated by the following table:
TV Broadcast Frequencies
|
Band |
RF Channel |
Frequency |
|
VHF-Lo |
2-6 |
54 – 88 MHz |
|
VHF – Hi |
7 -13 |
174 -216 MHz |
|
UHF |
14 – 69 |
470 – 806 MHz |
Note: Each TV channel has a bandwidth of 6MHz. For example, Channel 7 occupies 174 thru 179MHz.
See: http://otadtv.com/frequency/index.html
See: https://www.rapidtables.com
See: https://www.nocable.org
To be able to watch OTA TV, one needs to connect their TV to an Antenna – specifically designed to receive / pick-up TV signals – using a 75 Ohm coaxial cable.
A broadcast TV signal gets weaker as it travels through the air. Geography / terrain, buildings , trees an other physical obstructions can interfere with / diminish the TV signal.
Each TV Channel has its own set of radio frequencies that they transmit over (see table above). Radio Frequencies have a physical property called Wavelength (symbol λ). The higher the frequency the shorter the wavelength. Conversely, the lower the frequency the longer the wavelength. To know the wavelength of a specific radio frequency, divide the speed of light (which travels thorugh air at 983,600,000 feet per second) by the frequency. For example WCBS broadcasts on a UHF frequency of 602MHz (602,000,000 Hz). So its wavelength is 983,600,000 / 602,000,000 = 1.634 feet or 19.6 inches.
λ = 9,836,000 / 602,000,000 = 1.634 feet = 19.6 inches
All Antennas must be designed for the specific range of frequencies that they want to receive. The Antenna receiving elements should be tuned to the wavelength or band of wavelengths it wants to pick up. In other words an Antenna element should have a length equal to the wavelength it wants to receive. Turns out, if the Antenna element length is either 1/2 or 1/4 of the wavelength it wll work effectively. So for WCBS a 1/4 wavelength Antenna needs elements to be 4.9 inches long.
The FCC mandated that TV Broadcasters must convert from analog signals to digital signals by the year 2009. Digital signals allowed for a technology called multiplexing could simultaneously broadcast multiple TV programs over the same TV channel. Also, the FCC allowed Broadcasters to move from the VHF bands to the UHF Band, but still keep their traditional (Virtual) channel designation.
TV Station Transmitter Locations for Westfield New Jersey
|
(Virtual) Channel |
Call Sign |
Network |
Radio Frequency (Mhz) |
Band |
Direction |
Distance (miles) |
|
2 |
WCBS |
CBS |
602 |
UHF |
NNE |
11 |
|
4 |
WNBC |
NBC |
602? |
UHF |
ENE |
20 |
|
5 |
WNYW |
FOX |
578 |
UHF |
NNE |
11 |
|
7 |
WABC |
ABC |
174 |
VHF-Hi |
NNE |
12 |
|
9 |
WWOR |
My Network RV |
536 |
UHF |
WSW |
17 |
|
11 |
WPIX |
CW |
189 |
VHF-Hi |
NNE |
11 |
|
13 |
WNET |
PBS |
210 |
VHF-Hi |
ENE |
17 |
|
21 |
WLIW |
PBS |
678? |
UHF |
ENE |
21 |
|
25 |
WWOR |
My Network TV |
UHF |
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MyHogan 