FM Radio Receiver Circuit for Battery Supply

This is a schematic for radio receiver circuit. This circuit is based on the TDA7088T that can be used in mono portable and pocket radios. This is a bipolar integrated circuit. This is the figure of the circuit;


When a minimum of peripheral components (of small dimensions and low cost) is important, we can use TDA7088T. Frequency-locked -loop (FLL) system with an Intermediate Frequency (IF) of about 70 KHz is built on this circuit. By active RC-filters, selectivity is achieved. De-tuning related to the IF and the mute circuit is suppress too week input signals. [Schematic circuit source: NXP Semiconductor Application Notes]

AM/FM/SW Active Antenna Circuit

This is a circuit diagram for active antenna that can be used for AM, FM, and shortwave (SW). On the shortwave band this active antenna is comparable to a 20 to 30 foot wire antenna. This circuit is designed to be used on receivers that use un-tuned wire antennas, such as inexpensive units and car radios. This is the figure of the circuit.


L1 can be selected for the application. A 470uH coil works on lower frequencies ( AM ). For shortwave, try a 20uH coil. The unit can be powered by a 9 volt battery. If a power supply is used, bypass the power supply with a .04uF capacitor to prevent noise pickup. The antenna used on this circuit is a standard 18" telescoping type. Output is taken from jack J1 and run to the input on the receiver.

15dB UHF TV Antenna Booster Circuit

This is a circuit for antenna UHF TV that can be give 15dB preamp. This circuit is built by transistor and low components. This is the figure of the circuit.


The circuit above is formed based on BF180 UHF Transistor. The first stage is a band pass filter constructed by the C1, CV1, L1, L4, C7 and C3, the second stage is a base-common voltage amplifier with low input impedance to match. Build the L1 ~ L4 as air core coil to obtain high Q-Factor. After assembling, pack it into a proper metallic box and connect the ground of the circuit to the box to reduce noise effect.