Introduction, System overview | Sony ICF-SW77 specs

1 Introduction

1.1Purpose of this document

This document describes how to modify a Sony ICF-SW77 short wave receiver to be able to receive a DRM signal. Therefore the DRM – Miniature Mixer Unit from Sat-Service Schneider is used, to mix down the 455 kHz IF of the receiver to a 12 kHz IF. This 12 kHz IF is feed to a PC sound card.

Please note that the manufacturer's warranty will be discarded if you do this modification.

1.2Organization of this document

Chapter 1 provides an introduction to the document. Chapter 2 provides an overview of the system.

Chapter 3 describes how the IF filter of the ICF-SW77 has to be changed.

Chapter 4 describes how the DRM Miniature Mixer Unit has to be connected to the receiver.

2 System overview

The 2. IF (455 kHz) of the ICF-SW77 receiver is feed to the miniature mixer unit and down converted to a 12 kHz IF. This IF signal is then connected to the input of a PC sound card. This PC decodes the DRM signal with a decoder software.

ICF-SW77

455 kHz

mixer unit

12 kHz

3 Change of 455 kHz IF filter

The bandwidth of the ICF-SW77 receiver is too small to receive a DRM signal. Therefore the IF filter has to be changed.

3.1Schematic

The following diagram shows the schematic of the SW 77 IF section.

Date: 19-11-02

Page 3 of 8

ICF-SW77 specifications

The Sony ICF-SW77 is a versatile and sophisticated portable shortwave radio that caters to both amateur radio enthusiasts and casual listeners. Known for its solid performance and robust feature set, the ICF-SW77 has earned a place in the hearts of many worldwide.

One of the primary features of the ICF-SW77 is its wide frequency range, covering AM, FM, and shortwave bands. It can receive frequencies from 150 kHz to 30 MHz, making it suitable for picking up local stations as well as international broadcasts. The radio’s digital tuning system allows for precise frequency selection, ensuring that users can easily tune into their desired station without interference.

Equipped with a large LCD screen, the ICF-SW77 displays critical information, including frequency, band, and signal strength. The backlit display enhances visibility, allowing for use in low-light conditions. Furthermore, the radio features a memory function that can store multiple stations, providing convenient access to frequently listened-to channels.

The ICF-SW77 utilizes a high-sensitivity tuner, ensuring excellent reception, even in areas with weak signals. This tuner is complemented by a built-in digital signal processing technology that helps to reduce noise and enhance audio clarity. Notably, the SSB (Single SideBand) reception capabilities make it possible to listen to amateur radio transmissions, expanding the radio's functionality for serious hobbyists.

Another key characteristic of the ICF-SW77 is its dual power supply system. It can operate on both AC power or batteries, providing flexibility for outdoor use or during emergencies. The long battery life ensures extended listening sessions without interruption.

The build quality of the ICF-SW77 is robust, featuring a sturdy casing that makes it relatively durable for travel. Additionally, the ergonomic design of the device includes well-placed buttons and a comfortable grip, enhancing the user experience.

Overall, the Sony ICF-SW77 stands out for its exceptional performance, user-friendly features, and versatility. Whether you are looking to explore the world of shortwave radio or simply enjoy your favorite AM/FM stations, the ICF-SW77 delivers reliable performance and excellent sound quality, making it a noteworthy choice in the realm of portable radios.