lines immediately.Turntherange
control backtoyouroriginal depth
setting.
Toturnthe lines backon,simply
reverse the procedure by turning
therangecontrol to 10feet, hold
themarker switch"ON",and ro-
tatethernge control tothe20
feetposition. Lineswillbeprinted
onthe paper.Return therange
control tothedesired depth
setting.
Scale
Thenumbers that indicate the
depth orscale maybedeleted if
desired. Rotate therangecontrol
tothe 60feetposition, hold the
marker control "ON",andturnthe
range control tothe40feet posi-
tion. Thedepth scalewillno lon-
gerbeprinted. Therange control
now maybeturnedtothedesired
depth setting.
Toturnthedepth scalebackon,
rotatetherangecontrol to40feet,
holdthemarkerswitch"ON",
and
rotatetherangecontrol backto
the60feet position. Remember,
themarkerswitchmust beondur-
ingtheperiod
oftimethatthe
rangecontrol isswitched. Return
therangecontrol tothedesired
depth setting.
24 - -———- --—--———-
3b - - -— — — ________-Lb
HR —--- 4 --
by ——— - ERELE — bu--
Figure 34 SCALE"ON"
Transmitand Print Alternate
When using
the MACH 1 in deep
water, itmay bedesirable toslow
thepapersped downconsid-
erably.However,whendoing so,
youmayget 'over print"orvery
dark, heavy printing overan area
thatisdifficult toread.Much de-
tailcanbe lost duetothis.
An available feature istheTrans-
mit and Print Alternate function
which, when
activated, triggers
thetransmitter andcausesthe
stylus
toprinteveryotherrevolu-
tioninstead ofeveryrevolution.
Thisaccomplishes threethings:
1. Since thestylusonlyprintsev-
eryotherrevolution,there-
corded information is not
squeezed together
intoavery
small area. This allows
better
records atslowerpaper
speeds. Also, thescalenum-
bers are spread
outmore, so
theyare morelegible.
2. Preventsthe possibility of
"wrap around". Thisisthe un-
desirable occurrence ofthe
second orthird bottom echo
printed onthepaperatthetop
ormiddle ofthe page. Many
timesthiscaninterfere with
fish orother
targetsthatyou
wishtosee.
SuppressorControl
TheSuppressor Control is used
toreduce interference fromnoise.
Noise, in electronic terms,isany
undesired signal. Itcanbe
caused byan electrical source,
(suchastheengine's ignition sys-
tem), or byairbubbles in dis-
turbed waterwhichiscalled
cavitation noise. In both cases,
the noise could produce
un-
wanted marks onthe paper. (See
Figure7). Fortunately, noise
— —r HO —— —________
-- P -
:..çj—TT1:Iff...!J'1!Ijii— .-1 ---—- EQ ---——---————-EHIL
Figure6
pulses are relatively short in time
compared torealsonar
signals.
Advancing theSuppressor knob
willcausethesystem
toreject
theseunwanted, short pulses
without
reducing
thesensitivity
in
anyway. However,with highsup-
pression settings,
the
graphrec-
ord becomes coarseand the
ability to separatefishfromthe
bottom orfromotherfishwillbe
decreased. (SeeFigure9).
Therefore, the lowerthesuppres-
sion setting, thebetter. Advance
theknob setting onlyasfar as
necessary toremove the erratic,
unwanted noisemarks. Mostof
thetimeatlowortrollingspeeds,
nosuppressionwill beneeded.
However,it is helpful sometimes
to have longer pulse
widthswhen
noiseis notaconcern. When us-
ingasonarin deeperwater, itis
easier-for the unittodetectalon-
gerpulsecoming backfromthe
bottom orfrom thefish. Thisis
called"Probability ofEcho Detec-
tion".Theprobability oftheunit
being abletodetectanechore-
turning fromdeep wateris dimin-
ished because thefurtherthe
Figure7
EAGLE
Figure 35 SCALE"OFF" PROPER SEllING
16 Figure 8 Figure9
SUPPRESSION:TOO HIGH
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