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Digital Television Antennas and Reception
Over-the-Air Free TV

Digital TV | Improve Reception | Antennas | Summary | Installation | Signal Levels | Frequencies

DIGITAL TELEVISION (DTV)

UHF Antenna DTV requires a stronger signal than analog TV. Additionally, most DTV transmitters are in the Ultra High Frequency UHF band (channels 14 - 51). These signals are much higher in frequency and are Line-of-Sight -- do not pass through or around objects as signals in the Very High Frequency VHF band (channels 2 - 13). Also, over-the-air transmission losses are greater at UHF frequencies. Antennas that picked up analog TV signals will also pick up DTV signals, if the signal is strong enough.

DTV, RF and Analog Channels
The old analog TV channel identification used the transmit frequency channel number, technically called the Radio Frequency RF channel, DTV does not. A station's DTV channel may or may not correspond to it's RF channel. Most analog TV stations changed their RF channel for DTV, but were allowed to keep their old analog channel identification as their DTV or Virtual Channel identification. Because multiple programs (stations) can be broadcast within one channel, DTV identifications are virtual channel with a dot or dash for sub-channel (e.g. 69.1 or 69-1). Also see St Louis DTV Stations.

There are 50 RF channels designated for DTV, 12 channels (2 - 13) in the VHF band, and 38 channels (14 - 51) in the UHF band. The UHF band originally had 56 channels (14 -69), but was reduced by 18 channels (over 30%) to use the spectrum for other purposes.

IMPROVE SIGNAL RECEPTION
Angle Bearing

ANTENNA POINTING ANGLE
Most antennas are directional and must be pointed toward the transmitter broadcast tower for best reception. Most UHF antennas have a relatively wide beam ((best reception angles), but are less forgiving (more narrow beam) than VHF antennas. Adjusting an antenna's pointing angle may help pull in weak signals.

DTV Reception Maps (dtv.gov/maps)
- Virtual and RF channels / Band (VHF/UHF)
- Network / Callsign,
- Receive Power (dBm),
- Direction to Tower...
Enter location, click on TV station callsign for full information.

ANTENNA ELEVATION
The antenna should be located as high as possible and have a clear line-of-sight (no hills, structures, trees, etc.) to the transmitting towers. The higher the receiving antenna is above ground clutter the greater the signal density.


coax and twin lead cables

CABLES
Replace all twin-lead (300 ohm) cables with RG-6 coax (75 ohm) cables. Multiple shielded RG-6 has better immunity from interference, is more sturdy and durable, but is less flexible. Check all outside cable connections for corrosion, replace if necessary. Cable runs should be as short as possible.

Cable Loss Calculator
Depends on RF Channel
RG-6 Coax Cable
Cable Length: feet
RF Channel:

Signal Loss (dB)
Range Loss Percent (%)


Booster AMPLIFIERS
Long cable runs and signal splitter(s) may require installing a booster amplifier. A booster-amp will not improve a weak antenna signal, because it amplifies signal and noise, but it will allow for longer cable runs and more splitters. The amplifer needs a detectable input signal for a good output signal. The amps are powered by house current (110 Vac).


PRE-AMPS
Pre-amps are low noise amplifiers (amplifies signal but not noise) that mount to an indoor or outdoor antenna to improve a weak signal. The amplifier mounts to the antenna and works with a separate power unit inside the home that supplies power to the amp through the coax cable (center conductor). Most have an adjustable gain, most plug into a standard power outlet (110 Vac), some are powered from a USB connection.

ANTENNAS

Television antennas come in 3 basic frequency band configurations.

Band RF Channels Frequency
VHF 2 - 13 54 - 216 MHz
VHF/UHF 2 - 69 54 - 216 MHz
470 - 806 MHz
UHF 14 - 69 470 - 806 MHz

ANTENNA GAIN: Reception range doubles for a gain increase of +6 dB, and antenna size will quadruple. Antenna gain is expressed in dBi or dBD. Gain expressed in dB is usually really dBD, makes gain look 2 dB higher.

dBi = dBD - 2.15
dBD = dBi + 2.15
HOME ANTENNAS
INDOORs

INDOORs (with Preamp)

MODERATE SIGNALS

WEAK SIGNALS

SUMMARY
INSTALLATION

Typical Antenna Installation

Outside Antenna Installation
* Ground Block, Surge Protector, or Lightning Arrester
Check local codes for installation requirements and restrictions.

SIGNAL SPLITTERS more...

ATTENUATORS more...

ADAPTERS more...

RECEIVER SIGNAL

Analog receivers require a minimum signal to noise ratio (S/N) of 10 to 15 dB, signal must be at least 10 to 15 dB greater than background electromagnetic noise. DTV receivers require a S/N of 25 to 30 dB. Noise floor varies with atmospheric conditions, time of day, and proximity to transmitters and high voltage devices and lines.


Signal Level dBm dBmV mV
Good 100% -5 44 154
90% -11 38 77
80% -17 32 26
70% -23 26 19
Moderate 60% -29 20 10
50% -35 14 5
40% -41 8 2
30% -47 2 1.2
Weak 20% -53 -4 0.6
10% -59 -10 0.3
0% -65 -15 0.15
Noise -84 -35 0.02

dBm = decibels with respect to 1 milliwatt
dBmV = decibels with respect to 1 millivolt
mV = millivolts

RF CHANNEL FREQUENCIES
Each RF channel is 6 MHz wide.

TV VHF and UHF bands

UHF Band
Ultra High Frequency
300 - 3000 MHz

RF
Channel
MHz Band-
width
14 473 470 - 476
15 479 476 - 482
16 485 482 - 488
17 491 488 - 494
18 497 494 - 500
19 503 500 - 506
20 509 506 - 512
21 515 512 - 518
22 521 518 - 524
23 527 524 - 530
24 533 530 - 536
25 539 536 - 542
26 545 542 - 548
27 551 548 - 554
28 557 554 - 560
29 563 560 - 566
30 569 566 - 572
31 575 572 - 578
32 581 578 - 584
RF
Channel
MHz Band-
width
33 587 584 - 590
34 593 590 - 596
35 599 596 - 602
36 605 602 - 608
37 611 608 - 614
38 617 614 - 620
39 623 620 - 626
40 629 626 - 632
41 635 632 - 638
42 641 638 - 644
43 647 644 - 650
44 653 650 - 656
45 659 656 - 662
46 665 662 - 668
47 671 668 - 674
48 677 674 - 680
49 683 680 - 686
50 689 686 - 692
51 695 692 - 698
Ch 37 reserved for radio astronomy.

No Longer Used for DTV
RF
Channel
MHz Band-
width
52 701 698 - 704
53 707 704 - 710
54 713 710 - 716
55 719 716 - 722
56 725 722 - 728
57 731 728 - 734
58 737 734 - 740
59 743 740 - 746
60 749 746 - 752
61 755 752 - 758
62 761 758 - 764
63 767 764 - 770
64 773 770 - 776
65 779 776 - 782
66 785 782 - 788
67 791 788 - 794
68 797 794 - 800
69 803 800 - 806

VHF Band
Very High Frequency
30 - 300 MHz

RF
Channel
MHz Band-
width
Government and Public Service 30-50
Amateur Radio 50-54
2 57 54 - 60
3 63 60 - 66
4 69 66 - 72
Shared Use 72 - 76
5 79 76 - 82
6 85 82 - 88
FM Radio 88 - 108
Air Navigation 108 - 118
Aircraft Voice (AM) 118 - 138
Radar 138 - 144
Amateur 144 - 148
Police / Fire / Ambulance and Business 148 - 164
Public Service 164 - 174
RF
Channel
MHz Band-
width
7 177 174 - 180
8 183 180 - 186
9 189 186 - 192
10 195 192 - 198
11 201 198 - 204
12 207 204 - 210
13 213 210 - 216
Radar 216 - 225
Government 225 - 300

The Best of the Essentials
DTV Antennas and Accessories
Outdoor Antennas -- Indoor Antennas -- Amplifiers -- Signal Splitters -- Coax -- Installation Hardware

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