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MC3362 and ADF4351 based, modularized, NFM receiver. This receiver is designed to listen to the 2m band amateur radio conversations.

This project is about MC3362and ADF4351based modularized, 2-meter narrow band FM receiver. In this design, the receiver splits into three modules as RF preamplifier, MC3362 tuner, and ADF4351 oscillator. The RF preamplifier builts around BF900 dual-gate MOSFET. The tuner stage builts using the popular MC3362, low power narrowband FM receiver IC. For the oscillator, we use the ADF4351 DDS RF signal generator module.

The core component of this receiver is MC3362IC. This IC was designed by Motorola and is no longer in production, but this IC is still available to purchase in many online stores. The chip we used in this receiver was purchased from a local electronic component store for LKR 75 (USD 0.2).

The RF preamplifier used in this receiver extracts from the N.Ganesan’s (VU3GEK) LRR200, 2-meter band FM receiver project.

In this prototype, the above preamplifier was built as a module using a Manhattan construction technique. The SO-239 antenna input socket is also soldered directly to the preamplifier board. The preamplifier output connects to the input of the 1st mixer stage of MC3362 via a 50Ω coaxial link. This preamplifier is designed to operate using an 8V DC power source. If the BF900 transistor is not available, use an equivalent dual-gate, UHF range, N-channel MOSFET transistor.

The tuner stage of this receiver is a minimal version of the MC3362 circuit. This tuner module mainly consists of 10.7MHz and 455kHz ceramic filters, a 42IF301 - I.F transformer, and a 10.245MHz crystal. The local oscillator stage of this receiver is modified to use the ADF4351 RF signal generator. During the prototyping stages, we drive this module using a 5V DC power source.”

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