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Have a Garmin 545s and am brand new to saltwater fishing. What's the advantage to dual-beam or single beam, wide beam or narrow beam, (how wide or narrow are we talkin'??) Any reccomended frequencies to use, whats the difference between them??? Been out to a few local wrecks and having trouble staying on them, what speed should the screen scroll be at, something tells me we're not over what the screen says we are sometimes. The Garmin book that came with the gps is garbage and any tips you guys could give would be greatly appreciated. Thanks guys.
 

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Lets start with some of the basics. You probably have a duel frequency transducer, 50 KHrz and 200Khrz. The 50 is for deep water and the 200 is for shallow. The 50 shoots a wide beam, the 200 shoots a narrower beam. You cannot alter the width, just choose between them, and like I said above the 200 will read better in shallow water, the 50 will read better in deep water. I can read my 200 in up to 400' with no problems. Deeper than that I switch to 50. Some machines allow you to display the readings from both frequencies on a split screen. I've used this display but don't find it helpful. It takes away the data I'm looking for by reducing screen size.



I have my screen set to the fastest scroll. I also turn on My A-Scope. This will be a vertical display, just to the right of the bottom picture. The bottom picture is what has happened behind you. The A-Scope is what's under the boat RIGHT NOW,in real time. After an occurrence appears on the A-Scope, it is then produced on the screen to the left of the A-Scope display



First thing is to set the machine up so it's reading properly. Go to a depth close to where you will be fishing. Turn the auto-gain and auto-bottom off and turn both to operate manually. Turn the bottom to read just over double the depth of the water you are in, for instance, if you are in 40' of water, turn the depth to read 100'. Then increase the gain until you get a double echo. It will show a second bottom line at twice the actual depth. Then decrease the gain until the second echo is just visible. Now you have your gain set correctly, reset the depth to read the correct depth, if I'm in 40', I would set it to read 50'



I also use the feature on my machine, (Simrad EQ33) to look at just the bottom 15'-20' When bottom fishing, I don't really care what is in the upper water column. If my structure is in 140', I'm only looking at 125-145'



Hope this helps
 

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Instant Karma (3/27/2010)Practice...
this is what it's gonna take. do your home work and read up on your equipment. Garmin makes good equipment. you will figure it out. don't get aggrivated. on mine i have my map screen set up with a bearing and distace to window on it. when i get over my mark i hit the MOB button. then all the info to keep you there is right there. just takes a little practice.
 

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jlw1972 (3/27/2010)
Instant Karma (3/27/2010)Practice...
this is what it's gonna take. do your home work and read up on your equipment. Garmin makes good equipment. you will figure it out. don't get aggrivated. on mine i have my map screen set up with a bearing and distace to window on it. when i get over my mark i hit the MOB button. then all the info to keep you there is right there. just takes a little practice.


I've been using MOB also, but haven't hooked my Raymarine to my DSC radio yet.

I think MOB will fire off a DSC distress. not good.

Anyone have a raymarine connected to DSC capable VHF that could weigh in?
 

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reeltime (3/27/2010)
jlw1972 (3/27/2010)
Instant Karma (3/27/2010)Practice...
this is what it's gonna take. do your home work and read up on your equipment. Garmin makes good equipment. you will figure it out. don't get aggrivated. on mine i have my map screen set up with a bearing and distace to window on it. when i get over my mark i hit the MOB button. then all the info to keep you there is right there. just takes a little practice.
I've been using MOB also, but haven't hooked my Raymarine to my DSC radio yet.
I think MOB will fire off a DSC distress. not good.
Anyone have a raymarine connected to DSC capable VHF that could weigh in?
good point. i did'nt think of that. if your linked this is probably not the way to go.
 

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Jack Hexter (3/27/2010)Lets start with some of the basics. You probably have a duel frequency transducer, 50 KHrz and 200Khrz. The 50 is for deep water and the 200 is for shallow. The 50 shoots a wide beam, the 200 shoots a narrower beam. You cannot alter the width, just choose between them, and like I said above the 200 will read better in shallow water, the 50 will read better in deep water. I can read my 200 in up to 400' with no problems. Deeper than that I switch to 50. Some machines allow you to display the readings from both frequencies on a split screen. I've used this display but don't find it helpful. It takes away the data I'm looking for by reducing screen size.

I have my screen set to the fastest scroll. I also turn on My A-Scope. This will be a vertical display, just to the right of the bottom picture. The bottom picture is what has happened behind you. The A-Scope is what's under the boat RIGHT NOW,in real time. After an occurrence appears on the A-Scope, it is then produced on the screen to the left of the A-Scope display

First thing is to set the machine up so it's reading properly. Go to a depth close to where you will be fishing. Turn the auto-gain and auto-bottom off and turn both to operate manually. Turn the bottom to read just over double the depth of the water you are in, for instance, if you are in 40' of water, turn the depth to read 100'. Then increase the gain until you get a double echo. It will show a second bottom line at twice the actual depth. Then decrease the gain until the second echo is just visible. Now you have your gain set correctly, reset the depth to read the correct depth, if I'm in 40', I would set it to read 50'

I also use the feature on my machine, (Simrad EQ33) to look at just the bottom 15'-20' When bottom fishing, I don't really care what is in the upper water column. If my structure is in 140', I'm only looking at 125-145'

Hope this helps
Jack's third paragraph is the best advice I've heard... The A-scope hasn't helped me at all but the manual gain tuned set to just show a second bottom then up the scale to the first bottom works great.

Scientifically, that second bottom is a return from the same sound wave going back to the bottom and back up to the transducer again. Good gouge is your gain is set correctly when you can just see that second bottom. That's an OLD sonar trick... that way you KNOW it's strong enough to show reflections, but not too strong to ignore (blow right through)a "target" or piece of soft bottom.

I've recently heard about the bottom lock in his last paragraph... seems like a great idea though I like to see the whole water column sometimes.

If I'm running to a spot I leave it on auto (I think the garmins allow a "cruising" or a "fishing" mode. It's easier to run in "cruising mode" then switch to manual as you slow.)

Leave it in the dual mode as you run, you might pick up a spot along the way on one, but not the other (typically 200 Hz will be faster, but sometimes it'll pick up more turbulence from the prop or wave action too)

Some boats will give a return while on plane, some a poor return, others NO return. Mostly it's turbulence related around the transducer.

By the way... the transducer gives off a shallow clicking noise if you get close and listen... gain will control the volume (power)of those clicks, water clarity, density, bottom type, fish density, etc will determine the colors and intensity of the return. For the most part, fish are represented by "arcs" because the click is reflecting off the fishes air bladder which like a turd, tapers on each end.

Big "fogs" of returns usually means a lot (hundreds or more) small fish very close together = bait fish...

I could tell you how I know all this crap, but then I'd have too kill you...:reallycrying:reallycrying:reallycrying:letsdrink:letsdrink

Jim
 

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I don't know if this will apply to you,but I'll pass it along anyway FWIW. I was having real trouble staying on spots with my Humminbird and called the service people. I was told that all the tracks I was saving were slowing down the refresh on the GPS. Now I save any tracks I want to SC card and put them on my computer so that I have a minimum on the unit or on the SC card in the unit.

It helps. Now I wonder if the number of waypoints also slows things down. I think I'll call Humminbird again.
 
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