First Advisor

Robert Bass

Term of Graduation

Spring 2020

Date of Publication

6-17-2020

Document Type

Thesis

Degree Name

Master of Science (M.S.) in Electrical and Computer Engineering

Department

Electrical and Computer Engineering

Language

English

Subjects

Radio -- Transmitter-receivers -- Design and construction

DOI

10.15760/etd.7422

Physical Description

1 online resource (ix, 70 pages)

Abstract

This thesis outlines the design of a portable direct conversion transceiver system for the 7-MHz (or 40m) band. This band is popular due to its propagation characteristics which allow for world-wide communication with very low power. The transceiver utilizes a crystal-stabilized local oscillator optimized for frequency agility, low power consumption, and an optimal drive level of +7 dBm. A low power 8-bit microcontroller acts as an interface for either a straight key providing manual Morse code operation or digital logic control from a personal computer. It also acts as a side tone oscillator providing audio feedback to the operator during keying and reducing circuit complexity. Switching field-effect transistors (FETs) were used to change from transmit to receive with a switching speed of less than 300 microseconds and allowing for full break-in functionality. For the transmitter portion of the design, a dual-stage power amplifier was developed capable of power output levels greater than 30 dBm. Transmission tests were received at several locations ranging from Calgary, Canada to Tucson, Arizona having a maximum propagation distance of 1103.5 miles from the transmitter source.

Rights

In Copyright. URI: http://rightsstatements.org/vocab/InC/1.0/ This Item is protected by copyright and/or related rights. You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s).

Persistent Identifier

https://archives.pdx.edu/ds/psu/33657

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