Humminbird 161 - Manual (Page 9)

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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.