R80 Aviation Band PLL Receiver Double Frequency Conversion Aviation Radio Aircraft Tower Call Finished

Manual Click here to openDescrition 1 Use PIC18F1320 single chip microcomputer as main control built in PLL local oscillator module red LED frequency display display unit is 100KHz receiving frequency covers 118 136MHz 100KHz or 10KHz stepping refer to the figure below free switching 2 Using band pass filter high amplifier NE602 MC3361 TA7640 LM386 to complete the secondary conversion one intermediate frequency 10 7MHz two intermediate frequency 455KHz ultra high sensitivity can receive 118 136MHz AM signal 3 With LED tuning indicator function it can help to adjust the receiving frequency accurately and quickly which is convenient to use 4 It has a squelch circuit and freely set thresholds to ensure comfortable listening and avoid long term noise At the same time use the audio dedicated digital potentiometer FM62429 to adjust the squelch threshold and volume 5 The first and second intermediate frequency circuits all use ceramic filters which greatly reduces the difficulty of amateur commissioning 6 PCB board size is 8 4 12cmTips Because the VHF band is similar to the propagation of light linear propagation the receiving location is free from the airport but the distance is longer more than 25Km Please be sure to install a high gain antenna such as the VHF section Yagi antenna there is a distance between the receiving location and the airport Large obstacles including but not limited to tall buildings mountains giant towers must b