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I would be grateful for a professional translation or
correction of the following text! Amplifier of signal to reinforce antenna sign, for TV ( booster ) VHF, UHF, and radio FM
That is a small amplifier of signal, band releases, that
copper the frequencies from 40 to 900 MHz. Those frequencies
include TV in VHF and UHF and also radio in the frequencies of 88
- 108 MHz, strip of FM.
the signals in up to 20 dB, becoming possible to receive even
the weakest signals.
Characteristic and Specifications technique for booster with bfr90
- Answers of Frequency: 40 - 900 MHz
- gain: 20 dB
- Maximum level of output: 90 µV
- Input-output impedance: 75 ohm
As Works the circuit of booster bfr90
The circuit is built in turn of an only transistor of low signal
for UHF, BFR 90. This transistor can operate as loud as 1.6 GHz
in frequencies, and it has an gain of 23 dB. The signal of the
antenna is applied the input of the circuit and for C5 it is
coupled to the base of the transistor. It is amplified and of the
collector of BFR 90, through C2 and C1 it is taken the input of
RF of the radio or receiver of TV.
The circuit operates with a battery of 9V small that, because of
the very low consumption of the circuit, it will last plenty of
time.
Construction circuit amplifier tv vhf uhf
The project is very easy. The only uncommon thing is that the
transistor should be soldier of the side copper of the board.
However, that is common with devices of UHF and it is usually
done to avoid the introduction of capacitances parasites among
the terminals of the transistor that it could alter the operation
of the circuit. Be careful when doing the solder, try to maintain
the terminals of the component as close as possible, because of
the discharges involved frequencies. Weld the resistor in first
place. The reels should be ready to be a soldier in the circuit
printed and you should worry if of not deforming them in the
process. Place the capacitors, and weld the diodes it avoids to
heat up them in surplus and be sure that they are correctly
aligned. Weld the transistor to heat up it too much, and be
careful for you place it in agreement with the diagram. (The name
in the body of the transistor must it gives placed upward). The
input of the circuit is in the point 4 and to the earth and the
output in the point 1 and to the earth. The battery uses the
battery clip called in the points 2 (-) and 3 (+),é a
battery of 9 V, if you prefer it can be alkaline. For better
acting and to avoid interference undesirable during operation is
recommended to place the circuit in a small metal box, and to use
the mounted connectors in the box for the external connections.
You can use a big box enough, for the amplifier and the battery
or you to camp can use a source of external feeding, but it
remembers to use a capacitor of passage in the line of positive
feeding where to cross the metal box. If you plan to use the
amplifier to reinforce antenna sign for reception of TV in VHF and UHF, you should use a
splitter common for VHF/UHF before the input of the
amplifier.
Components for assembly the booster
R1 = 82 Kohm
R2 = 270 ohm
R3 = 1,5 Kohm
R4 = 120 ohm
C1,C3 = 100 PF
C2 = 2.2 pF
C4,C5 = 1 nF
D1,D2 = 1N4148 diode
Transistor = BFR90, BFR91, BFR90,
Several = PCB, solder, battery 9V, metallic box, clip to
battery, etc.
L1, L2=diameter: 5mm thread diameter:0,5mm turns: 8
Information's about Transistor bfr90
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Side of the components
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Dimensions (4,3cm x 5,4cm)
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Assembly of the Transistor
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