From: ed.mccrudden@rose.com (ed mccrudden)
Subject: What fish finder
Organization: Rose Media Inc, Toronto, Ontario.
Date: Sat, 12 Dec 1992 11:43:26 GMT
X-Gated-By: Usenet <==> RoseMail Gateway (v1.70)


Date Entered: 12-11-92 12:51
In article <1992Dec11.153635.29800@ncsu.edu> Pat L. Heron writes:

PH>I don't agree, for moderate depths LCD's are fine.

That's true, but they are still toys, filled with ridiculous and useless
features aimed at inducing gullible fishermen to open their wallets.
How about that wonderful feature where they put cute little fish icons
up on the screen?  Some of them even profess to be able to identify the
species for you.  Yeah, sure.....

PH>Peak power is a better indication of the amount of accoustical energy
PH>that gets put in the water for each sonar pulse.

I'm not so sure about that, but I'm not sufficiently schooled to argue
the point effectively, so we'll let this one slide.

PH>The more power that goes into the water, the easier it is to discriminate
PH>underwater objects and reject noise (except for very shallow water
PH>situations).

I consider twenty feet to be a "shallow water situation", but I certainly
do agree that more available power is better.

PH>Cone width of a 20degree cone at 20ft is just under 7ft.

I'm surprised to hear it is that large, but my point is made.  How many
fish can you expect to see in a seven foot circle directly under the
boat?

PH>However, if you are looking for channel edges and other bottom
PH>features (even in shallow water) the wide cone angle stinks.
PH>The sonar will mark the depth depending upon the minimum return time
PH>of the sound.                                    ^^^^^^^ ^^^^^^ ^^^^
   ^^ ^^^ ^^^^^

Ah!  Yessir!  Absolutely kee-rect!  But I believe the gentleman who asked
the original question wanted to see _fish_.

PH>The arches are only present when the boat is moving.

Bingo again!  <good explanation deleted>

PH>   20ft     /
PH> *************           ***
PH>             *           * ****
PH>             **          *
PH>              *         ---------channel bend filled with
PH>               *    **  *        giant starving fish.
PH>               *   ***  *
PH>                *  * *  *
PH>                * ** *  *
PH>   50ft              * **
PH>                      *

Heh!  Giant starving fish!  I love it!!

PH>The sonar will not see the channel unless the whole beam
PH>falls into it,

That's true, some portion of the 20 foot bottom will always be in the
cone.

PH>in shallow water most of us look for productive fishing structure,
PH>not fish!

You might as well, because sonar just doesn't mark a lot of fish
in shallow depths.

EM>The 20 degree transducers that come with the Mach-1 or the X-16 are no
EM>good for shallow water.  Even if you could fire their entire 200 watts
EM>RMS into the water (you can't), you'd only be looking at a two foot
EM>circle down there.  You need a 45 degree (or wider) transducer.

PH>I disagree!

What part do you disagree with?  The size of the circle?  Ok, that was
just a guess, to illustrate that the cone isn't very big twenty feet
down.  Do you disagree that a wide cone is better for *someone who
wants to see fish* in shallow water?

I personally would take the X-16 with the narrow cone over ANY of these
LCD units, but I think trying to mark fish in twenty feet of water is
a waste of time.  And I think we agree on that.

BTW, why are we discussing this here?  This newsgroup is supposed to
be defunct, now that rec.outdoors.fishing is going strong.

-Ed
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