: Multiple sonar installation - best practice


HudsonJohn
01-26-2005, 07:15 AM
I will soon be rigging my new boat with multiple sonar/gps units and would like some advice on the best practice in doing so to avoid transducer interference between the bow unit (on trolling motor) and the transom unit. I am looking to install 2 Lowrance 332c's. I have researched this in great deal and have discovered the following practices:
1.) Install a 200mhz transducer on both the front and back, and "deal with it", ie, one will interfere when you get past a depth a 30 feet or so (depending on length of boat). Just turn off one unit. There is some limited benefit to adjusting the "ping" rate on one of the units, though, I have not seen data that this really works.
2.) Install a 50/200 dual freq transducer in the back and a 200 in the front. This is more likely to work, but there still can be issues, as Lowrance uses sound waves from 50-200 when in the 200 mode. You also lose target resolution when in 50 and you should not thru-hull mount a 50/200 transducer (I prefer to thru-hull mount my transducer)
3.) Try Hummingbird, where one can supposedly change the broadcast frequency of the transducer?? I'm not a big Hummingbird fan though...

Looking for best practices from all of you expert Walleye boat folks.

Thanks.

John

Burr ND
01-26-2005, 07:47 AM
IMO, you need to get at least 40 khz separation between your units. So, can you alter your sonar purchases to include one 200 khz and one 120 khz?

That being said, I think the most current models seem to control cross talk better than those of years gone by. I can't give you any basis for this statement other than on the water time in boats that have two 200 khz ducers.

CASEY GIBSON
01-26-2005, 10:04 AM
So what good is it to have 2 graphs on board if you can only run 1 at a time.Right now I have a LMS-335 and I am getting ready to mount a LCX-15CT and it sounds like I might run into some issues then.

Burr ND
01-26-2005, 10:35 AM
I don't know if it is worth getting too upset about.

First, you should only have potential for problems when your sonar cones overlap. Many times with todays 20 foot boats, that means you will only start having these issues in 30+ foot of water.

Second - Why have 2 sonars - The bow mount sonar doesn't do you much good when you are navigating on plane, and the console mount doesn't do you much good when running your electric from the bow. Add to that moving one sonar from console, to bow, to console, would be very tiring.

Third - As stated, many anglers, both avid and professional, have the same khz on both bow and console. Without any basis, it seems like newer electronics are having fewer problems with cross talk. So you have a shot based on luck if nothing else.

That being said, IMO, the best approach you can take when riggin your boat to avoid a potential problem, is attain 40 khz separation minimum.

Also, side scan sonars really play havoc with everyone elses sonar you fish by. If you want to make a crowd owly in short order, have a side scan sonar - they kind of upset me...

I don't know if cross talk is damaging to electronics or not. Maybe someone else could answer that question.

fishin4fun
01-26-2005, 10:36 AM
One thing that will work is the Vexilar Edge LC507. It uses 107 khz and 400 khz. It won't interfere with your other sounder. Its a little pricey but it will work.

Albe
01-26-2005, 01:33 PM
I assume that the front transducer will be on your trolling motor.

Listened to Bruce "Doc" Samson on WYLL AM radio last Saturday and learned something new again from him. He said that he mounts the transducer on his trolling motor so it is angled 15-20 degrees forward by putting a shim under the back side of the transducer. That way when he sees a fish and it goes off the screen he can turn it quickly to the left and right to see if the fish moved out to the side of the boat if he sees it again. Also it shows fish further ahead of the boat in the direction he is going.

Also you can change the ping speed on the rear unit when you are using your trolling motor which may cut down on the interference.

Albe

HudsonJohn
01-26-2005, 03:48 PM
Interesting concept. Tough to do when you have the universal sonar MK Maxxum trolling motor... The other benefit of doing this, which I believe you were eluding to, is the fact that the cone is pointed further ahead of the boat, which allows you to fish deeper without the inteference being an issue.

Does one have to change the ping rate every time? It seems to me, that the rate is dependent on when both of the units were turned on with respect to one another...

Thanks for the info.

John

HudsonJohn
01-26-2005, 03:48 PM
Interesting concept. Tough to do when you have the universal sonar MK Maxxum trolling motor... The other benefit of doing this, which I believe you were eluding to, is the fact that the cone is pointed further ahead of the boat, which allows you to fish deeper without the inteference being an issue.

Does one have to change the ping rate every time? It seems to me, that the rate is dependent on when both of the units were turned on with respect to one another...

Thanks for the info.

John

Albe
01-26-2005, 05:01 PM
You would only have to change the ping rate if you have the interference. I would leave the TM at 100% and just change the back unit if you are using both at the same time. Only would take a maximum of 10 seconds to change the ping speed. Press menu once, go to Ping Speed, adjust, press Exit and it is done. You could also just press menu, go to Stop Chart, press Enter and press Exit. That stops the transducer from pinging but leaves the GPS screen still working.

If you are just leaving the back unit for someone in back to look at, I would adjust that unit until you have the least interference on the TM unit. The back unit may have more interference but if you are running the boat, the TM unit is the most important.

Albe

Albe
01-26-2005, 05:01 PM
You would only have to change the ping rate if you have the interference. I would leave the TM at 100% and just change the back unit if you are using both at the same time. Only would take a maximum of 10 seconds to change the ping speed. Press menu once, go to Ping Speed, adjust, press Exit and it is done. You could also just press menu, go to Stop Chart, press Enter and press Exit. That stops the transducer from pinging but leaves the GPS screen still working.

If you are just leaving the back unit for someone in back to look at, I would adjust that unit until you have the least interference on the TM unit. The back unit may have more interference but if you are running the boat, the TM unit is the most important.

Albe

Dutchman
01-26-2005, 05:06 PM
Pinpoint Sonar units are designed to work together at the same frequencty at the same time. They still have the patent, it's unfortunate the Brunswick is just sitting on this Pinpoint technology and not attempting to build it into a big screen color unit. As one other person stated the Vexilar Edge is another choice. Usually you won't get crosstalk from bow to transom until you get deeper that 14-16'. I know with my LCX104C I cannot have any other unit running in the boat or it goes whacky. My Vexilar FL18 and Pinpoint 7520 are a little more forgiving. I actually run these side by side on my bowmount with great results from both units. I have to adjust the FL18's sensativity, but they both read well. My tourney partners boat has a Lcx104C and a Genetron running at the same time and they work excellently together.


"Fishing is the pursuit of what is elusive but attainable, a perpetual series of occasions for hope"

Dutchman
01-26-2005, 05:06 PM
Pinpoint Sonar units are designed to work together at the same frequencty at the same time. They still have the patent, it's unfortunate the Brunswick is just sitting on this Pinpoint technology and not attempting to build it into a big screen color unit. As one other person stated the Vexilar Edge is another choice. Usually you won't get crosstalk from bow to transom until you get deeper that 14-16'. I know with my LCX104C I cannot have any other unit running in the boat or it goes whacky. My Vexilar FL18 and Pinpoint 7520 are a little more forgiving. I actually run these side by side on my bowmount with great results from both units. I have to adjust the FL18's sensativity, but they both read well. My tourney partners boat has a Lcx104C and a Genetron running at the same time and they work excellently together.


"Fishing is the pursuit of what is elusive but attainable, a perpetual series of occasions for hope"

SS2
01-26-2005, 08:28 PM
If you use a high speed on the bow instead of a puck you can adjust it to whatever angle you want. Helps a bit when contour trolling (credit to Rocketman's web site). Never tried pivoting the motor to see which way a fish went but it's an idea. No good if you want to see your baits vert jigging.

You'd have to do some homework to confirm it would work for your length of boat and the depths you want but a least a few models of sonars use narrower cone angles. If I remember 20 degrees gets you about a 10 ft circle in 30 fow? Running a 12 degree & a 20 degree might get you there if none of the alternative frequency options strike your fancy. I'd talk to the vendors tech support before acting on it since I run two 20's and if both are pointed down, I'm good in 20 fow but get interference around 30 fow and the cones should be 6 ft apart on my 16...:) maybe something to do with that bubble shaped thing they vendors always show with the "flashlight beam" cone angle illustrations?

Good Luck,
Silentsixty

Sounder
01-29-2005, 09:11 AM
You can do it. I have done it. Angle the transduces slightly apart from eachother. Plan to spend a little time tweeking them when you first set it up. Let me know if you need any other help.

Sounder