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Head amplifiers
Head antenna amplifiers with multiple outputs
Application : Head antenna amplifier with high output level, 4
4×120 F
Input 1 : FM Ch 2 -4,
Input 2 : VHF Ch 5 - 12 S11-S20,
Input 3 ( wide ) : S21 - S40 UHF Ch 21-69
Input 4 ( narrow ) : UHF Ch 21 - 69
Amplification : Amplifier VHF 10-28 dB, Amplifier UHF 12 - 32dB
Output level : 4 outputs of 120 dB/ìV
Input voltage : Linear power supply 210VAC -250VAC / 12.8VDC
Channel reject filter : -10 dB at 935 MHz
Indications : Led indication for high intermodulation VHF and UHF
dB
40
30
VHF
FM
20
10
0
0
UHF1
UHF 2
500
0243
1000 MHz
mistral
Antenna Systems
inputs and 4 outputs
4x120 code 0243
Intermodulation
indication for
VHF and UHF
IN UHF
C21- 69
IN UHF
C21- 69 s21- s41
IN C5-12
s11-s20
IN FM C2-4
Switching 12.8V
0243
OUT 1
OUT 2
OUT 3
OUT 4
Application of installing 2 VHF-UHF antennas and 12 downleads with the 4x120 amplifier
You should pay attention to these
Choose multichannel antennas especially for the UHF.
Ask to see the gain diagram which should be as straight as possible. There
should be less than 3 dB difference in the whole band. Antennas with such
characteristics are the logarithmic, they don't have great gain but they are very
linear.
When raining, care should be taken in order to avoid water sliding down through
the antenna cables to the amplifier because there is a great risk of electrocution.
Make sure you connect all the splitters to the outputs and that you attach a
cable to every splitter.
Adjust the amplifier by checking the indication light of the distortion
(if such a system exists) and make sure that there is no intermodulation of the
amplifier by checking the image quality especially of the weakest channels.
Ground the whole installation in a trustworthy grounding point, it will help in the
lightning protection. Good grounding point is the splitters' mounting points. The
good quality splitters have a special grounding screw on them.
Don't enclose the amplifiers in small boxes because the air has to be circulated
in order to cool the amplifiers. The high output amplifiers like the 4x115 and
especially the 4x120 require sufficient cooling otherwise there are going to be
interruption during summer because of the internal protection systems they
have.
If they are installed in a box, the temperature should not exceed 50 degrees C.
Logarithmic
antenna
Grounding
screw
24
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