Effective UHF for the receiver. Scheme, description

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ENCYCLOPEDIA OF RADIO ELECTRONICS AND ELECTRICAL ENGINEERING
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Effective UHF for the receiver. Encyclopedia of radio electronics and electrical engineering

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Encyclopedia of radio electronics and electrical engineering / radio reception

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The UHF electrical circuit diagram is shown in Figure 1. The preamplifier is intended for use as part of a portable radio receiver using a short piece of copper wire with a diameter of 2 mm as an antenna. The bandwidth of the amplifier is 100 kHz ... 50 MHz, which allows you to get a good value of effective sensitivity in a wide frequency range.

Effective UHF for the receiver. circuit diagram
Fig.1. circuit diagram

The bandwidth indicated above is obtained due to the fact that the transistor VT1 has a galvanic (direct) connection with the second transistor of the amplifier. Negative feedback between stages is carried out through resistors R4, R6. In the absence of negative feedback, UHF has a sufficiently large transmission coefficient, so the actual transmission coefficient will be determined by the ratio of the resistances of resistors R6, R4. It is advisable to use a separate DC source (battery) to power the amplifier.

Author: V. Dubinin, Lipetsk; Publication: cxem.net

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