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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.
Advisor: | Bass, Robert |
Commitee: | Pejcinovic, Branimir, Sanchez, Erik |
School: | Portland State University |
Department: | Electrical and Computer Engineering |
School Location: | United States -- Oregon |
Source: | MAI 82/3(E), Masters Abstracts International |
Source Type: | DISSERTATION |
Subjects: | Electrical engineering, Engineering |
Keywords: | Analog, Design, Digital, Hardware, Radio, Transceiver |
Publication Number: | 27735832 |
ISBN: | 9798664783070 |