Installation manual

Simrad SH80
When you choose the TVG setting you can either switch it off, or
choose a
“X log R” value. The different settings determine how
much gain the sonar will use as time elapses along the X-axis. A
higher value for “X” will make the angle (C) steeper.
Default setting on the SH80 sonar is
20 log R.
What is the PP Filter?
PP Filter m eans “Ping-to-Ping Filter”. When this function is
activated, the sonar will compare the echoes f rom one ping with
the echoes from the next pings. If an echo is present at the first
ping, but then disappears at the next, the sonar will interpret this
as noise and reverberation, and remove it.
If you choose setting
Weak, the sonar will only compare two
consecutive pings. If you choose settings
Medium or Strong the
sonar will compare four and eight pings respectively.
Default setting on the SH80 sonar is
Medium.
About pulse form and length
On the SH80 sonar, you can transmit sound modulated as FM
or CW.
FM means “frequency modulated”, which means that the
frequency of the transmitted pulse is changed during the
transmission. In most cases this method will provide better echo
presentation and stability, and you will avoid excessive noise
and reverberation.
Default setting on the SH80 sonar is
FM Auto.Inthis
transmission mode, the sonar will automatically choose from a
set of different frequencies depending on the current range.
CW means “continuous wave”, which means that the
transmission frequency is fixed during the entire pulse. When
you use CW transmission you can choose the length of the
pulses. In a search phase under good conditions, you should try
setting
Long. If the conditions worsen, try to shorten the pulse
length. This will make it easier to distinguish the various echoes,
and the reverberation will be reduced.
About beam widths
A narrow beam will always reach further than a wide beam. This
is because the t ransmitted power of the sonar is concentrated.
Nevertheless, you can easily “miss” a school of fish if you make
the beam too narrow. If the range is reduced, it is the common to
use a wider beam.
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