Two transducers on the transom?

[DHaun]

I am thinking about installing a 797c2i next to an existing Humminbird 535 on my console. A buddy mentioned I might want to keep the existing 535 unit as an additional sonar view. Sounds like good plan, but I am not sure if that is a good idea or not since both have 200khz transducers...

Question: Is this a viable configuration or will the 535 transducer on the transom interfere with the 797c2i transducer if mounted a short distance away? Are there any special mounting or interference considerations in maintaining distance between the 2 transducers.

I posted this on the side-imaging forum but figured there might be a guru on CFF that knows something on this topic as well.

Thanks!

 

[Guest]

David, why have two fishfinders running at the same time on the console? Put the new one on the console and keep the front one on your trolling motor, get rid of the old one on the console. With these two going, I don't believe a fish will get by you.

 

[blazer]

on my previous boat i had 2 transducers on the transom and did not seem to be a problem,what might creat a problem though is if you run both electrical wireing down the same side of the boat,you may get some interference and false readings from that.i would run the new wireing down the other side of the boat if possible.

 

[nwright]

The odds are against you. I have two Lowrance units in my boat that use 192khz transducers (sump & transom) and I get a lot if interferance. I can't have both on. I also have a unit on the trolling motor that uses a 200khz xducer and get no interferance using it in conjunction with either 192khz. I have a friend that uses two 200khz units, one on the trolling motor and one in the sump and he gets interferance on both, but it is not so bad as to render them useless.

 

[DHaun]

2 units provide more screen space. Sonar/Depth/Temp on one unit and then a combo GPS Map/Side-Imaging view on the other. I was thinking I would simply remove and replace the old 535 until it was recommended that I might want to just keep it. I am sure I can get by with one unit, but the 797 has a small screen area and I'll probably have to press buttons to constantly rotate between the combo views. Not sure if they can co-exist but it would also save me some removal effort if I could keep the old one.

 

[Guest]

David, just keep the old one on the dash and put the new one right beside it, you don't have to use both at the same time. You can try both at the same time and if you have interference, shut the old one down, take it off when you get a chance. I don't think you will have any interference with one running at a time.

 

[SpurHunter]

I remember a recent conversation here with more info about using two of the same power transducers. I think Cheez had some pertinent info on it, since he has a lot of interference trying to use both. You might PM him to see what his opinion was.

 

[Bee21]

I have tried this in several different ways, but regardless there is some inter. Most of the time the interferance is easy to distinguish from the true readings. Also you could run the second unit on gps only when needed. If it doesnt have that mode then simply unplug the transducer wire from the back of the unit. Further more I find it reasurring to flip units and look at the same spot sometimes. Helps me get my signal strenght where I want it.

 

[MrWiskers]

I would be shocked if you did not get some nasty interference. I have a Lowerance on the trolling motor and the 797 on the transom and I get a little interference at times. I would think two transducers putting out the same siginal in very close proximity would produce interference.

 

[Guest]

David I have a problem with my 777c2 transom mount and my 343c trolling motor mount. I get all kinds of distortion and false images and lines when they are both on at the same time. Playing with the sensitivity will reduce the problem but you still have false readings. I called Humminbird and their tech told me that 18 feet was not enough separation for these two units that both have 200khz transducers. They both try to read each others feed back signal as well as their own. You can call Humminbird but I think the problem would be even worse if both transducers were on the transom. You can solve the small screen problem by going to the 997SI unit but it will cost you about double.

 

[DHaun]

Thanks Guys - Based on what I have learned I'll probably be replacing the existing unit. Although some have pulled it off using filter settings, the Humminbird rep on the side imaging forum recommends against 2 side by side units.

 

[SNUFFY]

I`m using an x-70 on the trolling motor and the 332c ...as well as the in dash Lowrance Flasher in the sump/ transducer box. No problems with the TM x-70 with either of the others, but with the two on the back.... only one at a time will work.

 

[flip1up]

David, I have the same problems stated above trying to use 2 units at a time on the dash with both ducers on the transom. With just the 480 gps on it works great at all speeds. No problem for me with 1 on the transom and the other on the trolling motor though.

 

[hl&s]

I ran across this interesting info on the Lowrance support faq site. Hummingbird's support didn't return the same info but did give info for using a switch to select between the two sonars.

"Can I install two transducers (sounders) on one boat?
Anytime you use multiple transducers (sounders) of the same frequency, it is possible for them to interfere with each other. This is despite any specified distance between them as coverage areas and depth of water generally allow each to crosstalk. This appears as two specific fault indications. Dark vertical bars will appear on one sounder displaying the transmit burst of the other sounder. This cannot be changed but it is more livable than the other fault. If one unit picks up the echo return of the other unit, it can rapidly change from reading 20-30 feet to suddenly indicating 300- then 500- then 800 feet etc.

This effect can be reduced or eliminated using the ping speed controls of our latest models of sonar devices. When a unit jumps depth ranges, adjust the ping speed 1 setting slower, this will change the rep rate, and cycle time so that the sonar devices cannot sink up together. This will reduce or completely eliminate this problem. "

The last paragraph may help some with two newer sonars running simultaneously. I don't know if Hummingbird offers a ping speed adjustment on their units but my 522c does. I'm installing a 520c on the same boat, which also has a ping speed adjustment, and will see what happens.

Maybe Hummingbird has the same adjustment but calls it something else.emoScratch

 

[jon the fisherman]

since the side image uses 455 khz and the 535 is 80/200khz, I would not think there would be any problems. I have a shoot thru 200khz garmin on the console and the si next to it, and have not had any problems.

 

[Fuzzy]

I'm with JTF, but my front and console are x-135 Lowrance's and the Side Imager. I get some interference, but nothing that is so bad that I can't live with. If it was, I can just shut one off. I am of the opinion that more graph more info...