Antenna amplifier
Encyclopedia
In electronics
, an antenna amplifier, also called antenna preamplifier, antenna preamp or antenna booster, is a device that amplifies an antenna
signal, usually into an output with the same impedance
as the input impedance.
Typically 75 Ohm for coaxial cable
and 300 Ohm for twin lead cable.
An antenna amplifier allows a weak radio signal to be detected, thus most devices that receive radio wave
s already have an RF amplifier stage in the front end that amplifies the antenna signal.
The KEY is that you want a relative "good" level of input at your receiver
(TV) with the minimum noise.
A mast mounted amplifier (doesn't matter if it is called an amplifier or preamplifier) is the best when you are in a remote area.
In theory it is best if you amplify a "clean" signal to a higher level than a "noisy" signal to a higher level.
All cable has loss and the higher up that you go in frequency (VHF to UHF) the more loss that the cable has.
If you start with a low level signal at the antenna and then butt it into coax cable, you are going to have less come out at the other end than went into it from the antenna.
The amount of loss depends upon a number of factors, cable type and cable length are the two most important. Cable is rated in db loss per 100' at X MHz (frequency). RG-6 cable is the cable most used
in TV use. Like all things there is good RG6 and not so good.
as a example, Belden
1829AC Coax - Series 6 has a loss of 4db/100 feet at 500 MHz (TV Channel 18)- 495.250
Channel 32 which is 580 MHz,
Channel 52 is 700 MHz a 5 db loss
At TV channel 2, the cable would have a loss of 1.4db.
So at channel 18 you would loose more than 1/2 the power in 100' of cable between the antenna and the TV.
A amplified indoor antenna
does absolutely nothing for reception, since we all know that the only purpose of the amplifier is to overcome long lengths of wire and not to physically make the signal look larger.
Amplifiers amplify everything, Both the signal present at the antenna and the noise, both ambient background noise
(electric brush noise, gasoline engine ignition, electric fence
, etc.), the noise generated by the amplifier itself and all other electrical noise.
When the level of noise is louder than the signal, you will have no signal.
Electronics
Electronics is the branch of science, engineering and technology that deals with electrical circuits involving active electrical components such as vacuum tubes, transistors, diodes and integrated circuits, and associated passive interconnection technologies...
, an antenna amplifier, also called antenna preamplifier, antenna preamp or antenna booster, is a device that amplifies an antenna
Antenna (radio)
An antenna is an electrical device which converts electric currents into radio waves, and vice versa. It is usually used with a radio transmitter or radio receiver...
signal, usually into an output with the same impedance
Impedance
Impedance may refer to:*Electrical impedance, the ratio of the voltage phasor to the electric current phasor, a measure of the opposition to time-varying electric current in an electric circuit**Characteristic impedance of a transmission line...
as the input impedance.
Typically 75 Ohm for coaxial cable
Coaxial cable
Coaxial cable, or coax, has an inner conductor surrounded by a flexible, tubular insulating layer, surrounded by a tubular conducting shield. The term coaxial comes from the inner conductor and the outer shield sharing the same geometric axis...
and 300 Ohm for twin lead cable.
An antenna amplifier allows a weak radio signal to be detected, thus most devices that receive radio wave
Radio Wave
Radio Wave may refer to:*Radio frequency*Radio Wave 96.5, a radio station in Blackpool, UK...
s already have an RF amplifier stage in the front end that amplifies the antenna signal.
The KEY is that you want a relative "good" level of input at your receiver
Receiver
-Technology:* The listening device part of a telephone** The handset that sometimes contains the above device** The headset that can also contain the above device.* Audio-Visual receiver* Digital media receiver...
(TV) with the minimum noise.
A mast mounted amplifier (doesn't matter if it is called an amplifier or preamplifier) is the best when you are in a remote area.
In theory it is best if you amplify a "clean" signal to a higher level than a "noisy" signal to a higher level.
All cable has loss and the higher up that you go in frequency (VHF to UHF) the more loss that the cable has.
If you start with a low level signal at the antenna and then butt it into coax cable, you are going to have less come out at the other end than went into it from the antenna.
The amount of loss depends upon a number of factors, cable type and cable length are the two most important. Cable is rated in db loss per 100' at X MHz (frequency). RG-6 cable is the cable most used
in TV use. Like all things there is good RG6 and not so good.
as a example, Belden
Belden Inc.
Belden Inc.Belden Inc. designs, manufactures, and markets highly engineered signal transmission products for demanding applications. These cable, connectivity and networking products serve the industrial automation, enterprise, security, transportation, infrastructure, residential and consumer...
1829AC Coax - Series 6 has a loss of 4db/100 feet at 500 MHz (TV Channel 18)- 495.250
Channel 32 which is 580 MHz,
Channel 52 is 700 MHz a 5 db loss
At TV channel 2, the cable would have a loss of 1.4db.
So at channel 18 you would loose more than 1/2 the power in 100' of cable between the antenna and the TV.
A amplified indoor antenna
Indoor antenna
An Indoor antenna is a type of radio or TV antenna placed indoors, as opposed to being mounted on the roof. Indoor antennas are usually a simple and cheap solution that may work well when the receiver is relatively near to the broadcasting transmitter and the building walls do not shield the radio...
does absolutely nothing for reception, since we all know that the only purpose of the amplifier is to overcome long lengths of wire and not to physically make the signal look larger.
Amplifiers amplify everything, Both the signal present at the antenna and the noise, both ambient background noise
Background noise
In acoustics and specifically in acoustical engineering, background noise or ambient noise is any sound other than the sound being monitored. Background noise is a form of noise pollution or interference. Background noise is an important concept in setting noise regulations...
(electric brush noise, gasoline engine ignition, electric fence
Electric fence
An electric fence is a barrier that uses electric shocks to deter animals or people from crossing a boundary. The voltage of the shock may have effects ranging from uncomfortable, to painful or even lethal...
, etc.), the noise generated by the amplifier itself and all other electrical noise.
When the level of noise is louder than the signal, you will have no signal.