FM Receiver 144 MHz (simple and powerful)

 

Here is a VHF FM receiver very simp done using the components recovered from a wreck wireless phone. We'll have to unsolder two integrated circuits, the quartz filter 10F7.5A, a 10,245 MHz quartz, the ceramic filter and 455 Khz IF a pot.

Receptor plane (plans are handmade, but everything is)

Enlarge size

How does the FM receiver?

The signal from the antenna is filtered by a bandpass filter, it is introduced into low impedance at terminal 1 of the LA1185.
This pad has three floors, a HF amplifier, a mixer and a local oscillator.
The amplified signal enters the mixer at 4.
Between 8 and 9 is the local oscillator whose frequency is adjusted to 133.3 135.3 Mhz with a varicap diode. These diodes are installed in the original VHF television tuners.
In 6 we arrive at the IF output.
The resistance of 1.5 K and 3.3 K provide the impedance matching.
The circuit performs the MC3361 IF amplifier, the squetch and FM demodulation.
The classic LM386 amplification BF.

Cabling

Pho to the prototype

Conclusion

For two cents, you will realize a 144 MHz FM receiver.
Associated with the issuer already described on this site, you will have the opportunity to relay traffic to your local homebrew