Amplifiers in Antenna Installations
The information contained herein may be outdated.
Channel amplifiers (channel modules) - are used in medium and large-size community installations (MATV systems). They amplify individual channels (the main advantage) and are prepared (tuned) by the manufacturer (disadvantage). Their main parameters are: selectivity - showing attenuation of undesired signals (typically >25dB at one-channel spacing), and high maximum output level (typically >120dBuV).
Channel amplifiers, in comparison to other types of RF amplifiers, are characterized by a high gain, typically 40-54 dB, and a very high output level, more than 120 dB. They are dedicated for larger MATV/SMATV systems and their biggest advantage, besides the high gain and output level, is possibility of equalization of signal levels on each channel.
Typical noise figure is ca. 4 dB, and the gain 40 dB. It is possible to group them into sets, which are having two outputs. Channel amplifiers allow to adjust the gain within 20 dB range. In the case of a change of the channel there is possibility of retuning the channel module (the cost is about 10 EUR).
ZG-201 (R90512), ZG-301 (R90515), ZG-401 (R90517), ZG-601 (R90538) - typical channel amplifiers having high output level, for networks feeding up to 250 outlets.
A set of channel amplifiers can also be placed in a rack cabinet, using the SP-725 R912037 frame (it can carry up to 9 ZG amplifiers).
Building amplifiers - are used in community installations and cable TV distribution systems. One building amplifier is usually used for one staircase or a whole smaller building. The amplifiers have one broadband input, one output and often additional test output (usually -20 dB).
They are equipped with power supply and ensure compensation of cable attenuation (it can be adjusted within 20 dB range). Typical noise figure is 8 dB, and gain 40 dB. Their advantage is high output level (usually 120 dBuV), a drawback - they are rather expensive. They are often equipped with return channel.
Multi-input building amplifiers - used in medium-size installations (up to 50 outlets). They have band inputs with adjustable gain, but no cable compensation. The amplifiers typically enable to power preamplifiers via coaxial cables, have one output and additional test output. Are equipped with own power supply. Typical gain 35 dB, noise figure 7 dB, maximum output level 114 dBuV.
The most professional amplifier in this group of devices is Terra MA-203 R82323. It has 5 inputs: 1 x FM / VHF I, VHF III and 3x UHF. Each input ensures separate gain adjustment; summing up the signals from the FM / VHF I, VHF III, and 3 UHF paths it is possible to attenuate some of the signals by using 10dB attenuators. The UHF signals are combined in two stages: first, the signals from two inputs and then the signal from the third UHF input. This provides yet another opportunity to configure the weaker and stronger signals. The amplifier has a very high output level: 119 dBuV for VHF band and 121 dBuV for UHF band.
Subscriber amplifiers - used in small installations (up to 20 outlets), have one broadband input and two paths with independently adjustable gain in VHF and UHF bands. Typically they allow for powering antenna preamplifiers via coaxial cable. Their advantage is own power supply and low cost, similar to outdoor amplifiers (not equipped with own power supply). Typical gain 24 dB, noise figure 2-4 dB, maximum output level 102 dBuV.
- CA-210 (R90460) - for distribution of antenna signal in an apartment, house or small building, with low noise figure, may power preamplifier (24 V),
- CA-215 (R90461) - as above, may power preamplifier (12 V),
- AI-200 (R90450) - as above, without possibility of powering a preamplifier,
- AI-223 (R90452) - amplifier with 5-65 MHz return channel, for distributing cable TV in an apartment,
Band amplifiers and preamplifiers - used for amplification of low signals that are at levels below the specifications of channel of building amplifiers. They are quite cheap, especially compared with channel amplifiers. In very hard conditions there should be used channel amplifiers located directly by the antenna. Typical noise figure is 2 dB, gain 20 dB. They have one input and are powered via coaxial cable.
Outdoor amplifiers. They are used in small installations and usually equipped with band inputs with adjustable gain. There is anticipated possibility of powering preamplifiers, but no correction of cable attenuation (as the lengths are short). The gain is at a level 30 dB, noise figure 8 dB, maximum output level 110 dBuV. The amplifiers have only one output and are powered via coaxial cable. The main advantage is low cost, the drawback - exposure to environmental conditions which may increase failure frequency.
- AM-407 (R903031) - 4 inputs: UHF, UHF, VHF, FM
- AM-417 (R903717) - 4 inputs: UHF, UHF, VHF, FM
- AM-105 (R903008) - 2 inputs: VHF, UHF
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