Furuno FR-8111 - Manual (Page 26)

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1.6 Tuning the Receiver
The receiver can be tuned automatically or manu-
ally. The default (factory setting) is automatic tun-
ing.
Selecting tuning mode
1) Press the MENU key.
2) Select the INITIAL menu.
3) Press the ENTER/SELECT key.
Note: The above three steps can also be done
by pressing and holding down the MENU key.
4) Select TUNE SET and press the ENTER/SE-
LECT key.
5) Select AUTO (or MANUal).
6) Press the ENTER/SELECT key.
7) Press the MENU key.
Manual tuning
1) Select manual tuning by following "selecting
tuning mode."
2) While pressing and holding down the HM OFF
switch, adjust the trackball to display the long-
est tuning indicator.
MANUAL
Tuning indicator
Figure 1-7 Display appearance when
manual tuning is in effect
Note: The receiver may be detuned if your radar
is hit by another radar in vicinity. To retune in
automatic tuning, press the ST BY/TX key twice.
Video lockup recovery
Video lockup or picture freeze, can occur unex-
pectedly on digital rasterscan radars. This is
mainly caused by heavy spike noise in the
power line, and can be noticed by carefully
watching the nearly invisible sweep line. If you
suspect that the picture is not updated every
scan of the antenna or no key entry is accepted
notwithstanding the apparently normal picture,
turn the power off and on.
1.7 Adjusting Sensitivity
The GAIN control adjusts the sensitivity of the
receiver and thus the intensity of echoes as they
appear on the screen.
The proper setting is such that the background
noise is just visible on the screen. If you set up
for too little sensitivity, weak echoes may be
missed. On the other hand excessive sensitivity
yields too much background noise; strong targets
may be missed because of the poor contrast be-
tween desired echoes and the background noise
on the display.
To adjust receiver sensitivity, transmit on long
range, and adjust the GAIN control so background
noise is just visible on the screen.
1.8 Adjusting Picture Brilliance
The BRILL control adjusts the brilliance of the
picture.