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sonar/gps combo questions
#1
I'm looking at upgrading my fishfinder that came on my recently purchased Fisher to a sonar/gps combo but cant get a straight answer from the salesmen at the local places.I plan on fishing no deeper than maybe 150ft for lakers and maybe a rare trip to the ocean.Id like to keep the price no more than 700.00 too.The queations I have are what watt signal do I need for a good sharp picture.ONe guy told me 1500 would do it and another said 4000.I dont understand the duel frequency tranducer deal (50/200hrz?).And the other thing is with the gps.Will a model with an internal antenaa work through my canvas top or do I have to have one with an external antenaa?The models I seem to like are the Lowrance 525 and the 527.Same thing but one is internal and ones external.Any help would be great especially if anyone has these specific models.
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#2
to start off with the gps antenna,from personal experiance,i would go with the external.it is more sensitive,and less likely to lose a signal in inclement weather
Peak-to-Peak
Normally used to describe the output power of a sonar transmitter. This value is a measurement of the total swing of an AC voltage from its peak negative value to its peak positive value.

RMS Literally "root mean square"
A DC voltage that will produce the same heating effect (power output in Watts) as the AC voltage. For a sine wave, the RMS value is equal to 0.707 times the peak value of an AC voltage. Example: divide Peak-to-Peak by 2 (or in half) and multiple by 0.707 = RMS voltage

Now if you take 1500 Watts (Peak to Peak) and divide it by 2 multiply it by 0.707 (Root Mean Square Value), you end up with 530 Watts (RMS). This is indeed a powerful depth finder. Your looking at a depth penetration of about 800'.
Now, I guess you have to ask yourself when was the last time you caught a fish at 800 feet.

The good thing about having all that power is that it will cut thru a lot of debris, specially if you are fishing saltwater or water stirred up after a good rainfall. Another benefit is that it will give you a better detail of the bottom structure (e.g. sand, mud, clay, drop offs, boulders, heavy vegetation). This is the kind of information where you should be taking notes.

Trust me, it will make you a better fisherman. So much time is wasted because not enough attention is paid to the bottom. It comes down to, if you want to catch fish, you have to find them, and to find them you have to know where their habitat is especially at what time of year your fishing.

Another thing you should be looking at is the transducer angle. A 12 degree cone will give you a deep presentation but it is narrow, 20 degrees will give you less penetration but covers a wider area.
So, if your fishing 60 feet of water a narrow cone is pretty well useless to you.

A transducer's cone angle determines its coverage area of the underwater world.
The wider the cone angle, the greater the area that's covered.

Lowrance offers a variety of 200 kHz transducers with either a wide (20°) or narrow (12°) cone angle.

They also offer a variety of 192 kHz transducers with either a wide (20°) or narrow (8°) cone angle.

The 50 kHz transducers come with a 35° cone angle.

Dual-frequency transducers come with both a narrow (12°) 200 kHz and a wide (35°) 50 kHz cone angles and the dual-search transducers come with both a narrow (12°) 200 kHz and a wide
(35°) 83 kHz cone angles.

Generally, use a wide cone angle for fishing shallow to medium depths. The narrow cone penetrates to deeper depths, but shows less fish and structure due to its narrow beam. Remember transducers have to be matched with the transmitter.











What's the difference between wide and narrow cones?

A transducer with a wide cone (50 khz) scans more water and tends to lump things together whether it be fish, stumps, rocks, etc. A narrow cone (200 khz) can detect small details and focuses on structures at a greater depth. The diSadvantage here is that it scans a smaller amount of water.







feature a low profile for high speed performance. It's patented design helps prevent cavitation and other interference. [Image: 60degree.gif]To better describe the Skimmer® transducer think about it as your headlight view from your
vehicle at night.
The light beams directly ahead but it also shines off to the side. Now, lets say there are signs one on each side of the road and as you drive closer to them they become increasingly visible. This is termed periphereal. This peripheral is the 20 degree coverage you get on the sonar section of the Lowrance LMS-332C. The sonar covers a 60 degree angle in total. At a depth of about 20' it covers and area about 25'. The deeper the water the more area it covers.

Basically there are two types of transducers a 50 khz and a 200khz.

50 kHz [ul] [li]Deeper depths [li]Wide Cone Angle [li]Less Definition And Target Separation [li]Susceptible To More Noise [/li][/ul]
200kHz [ul] [li]Shallower Depths [li]Narrow Cone Angle [li]Better Definition And Target Separation [li]Less Susceptible To Noise[/li] [li][/li] [li][/li][/ul]
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#3
Noise[/url]
is visual clutter that appears on the display caused by unwanted signals being picked up by the fish finder.

just in case you didnt know what noise was
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#4
Tom gave you some really great info, but let me break it down for you. The average Sonar unit reads to about 600' or so. The expensive ocean based ones can read around 1800'. Being that you're only fishing in 150' of water, the 600' sonar is more than enough.

The article was speaking of penetration. If your max depth is 150', and the sonar reads to 600', you'll never have to worry about the sonar not being able to pick up the bottom. The transducer is 6 times stronger than it has to be.

I would insure that the dual unit you get is color. That makes a world of difference during peak daylight hours when the sun is shining right on the screen. The canvas won't make a difference either way. The GPS unit I use now is a hand held. I have a top on my boat and the whole nine yards. The weather has never stopped me from fishing, and the GPS has never lost a signal. Tom mentioned that the external attena is better, and sure it might be. But I consider that over kill. If you're not navigating a 60' sportfisher 100 miles offshore, than the super duper GPS isn't necessary. That would be like taking a 50 caliber sniper rifle to hunt squirrel.

The 525C unit you have been looking at is a fine fish finder/GPS unit. However, why exactly are you so hell bent on a duel unit? I've had them, and though they do the job, since i've went to single units i'll never have another double. I use nothing but lowrance equipment, even back in the days of Loran C before GPS's came out. I have a 21' Aquasport and mostly ocean fish, and I do it successfully. Just check my photo album. All I use is a Lowrance X67C sonar (240.00 bucks) and a Lowrance Ifinder H20 (140.00). About half the price, and in my opinion, more effective because you have more visial area and you can focus on one piece of equipment with out altering the other. The X67C has all the feature the big boys have as well, color monitor, zoom feature, fish tracking etc...., with out the big price. [cool]
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#5
I'm not exactly hell bent on a combo really,I just figured it would make navigating easier just looking at one unit instead of my finder and my portable GPS.Im pretty much a rookie when it comes to these things so simple would be better but I want to kake sure the untit will be outdated in a year or two.I like the idea of those SD card hotmap deals telling me everything about the lake too.Are those things available on the units that dont have gps? Would a 1500 watt unit do me fine or should I get bigger.I do tend to have a tendancy for overkill!I really appreciate your guys info, its a big help unlike to guy at Cabelas here.
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#6
yes a 1500 watt is good
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#7
My hand held is compatible with Navionics and other software. So, if you've got a handheld GPS of a newer make, it should be too. What kind of GPS is it? I can find out for you if you can use the map technology.
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#8
My handheld gps is an older Garmin,no way to upload maps to this ol unit.But on the bright side if a 1500 watt will do me than I can get a 1500 wat color unit and a new handheld gps for lessw than the 4000 watt unit with gps!I could use a new gps anyhow for hunting.
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