Humminbird 1158c Combo, Installation And Operation Manual

Page: 14 / 232

When all the echoes are viewed side by side, an easy to interpret
"graph" of the bottom, fish, and structure appears.
The sound pulses are transmitted at various frequencies
depending on the application. Very high frequencies (455 kHz) are
used for greatest definition but the operating depth is limited.
High frequencies (200 kHz) are commonly used on consumer
sonar and provide a good balance between depth performance
and resolution. Low frequencies (83 kHz) are typically used to
achieve greater depth capability.
The power output is the amount of energy generated by the sonar
transmitter. It is commonly measured using two methods:
• Root Mean Square (RMS) measures power output over the
entire transmit cycle.
• Peak to Peak measures power output at the highest points.
The benefits of increased power output are the ability to detect
smaller targets at greater distances, ability to overcome noise,
better high speed performance, and enhanced depth capability.
Introduction
2