Humminbird Side Imaging Forums
Side Imaging Forums => 798c SI => Topic started by: hamholfarm on June 09, 2010, 06:42:59 AM
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Hello,
I am about to become a member of the Humminbird family by purchasing a 798ci. I have been reading up on the various topics here and I am concerned about the interference people are experiencing with their trolling motors and TM mounted transducers. Do all brands and models of TM’s cause interference? Should I go ahead and get the Humminbird “Trolling Motor Choke” now because I will need it, or wait to see what happens and maybe save some money? I have a Johnson bow mounted, foot controlled trolling motor. I don’t know the year or model as I can not find any markings. The boat and main motor were purchased in 1988, so maybe the trolling motor is also from 1988. I don’t know how many previous owners there where, or what they may have done/purchased. I bought the boat from a used car salesman who took it in on a trade, and he knew very little about the boat.
Thanks for the help,
Chip
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Hi Chip, The interference is almost always from the trolling motors with Pulse Width Modulation. I doubt that vintage motor has it. If you are not using the same battery as your trolling motor you should be fine. Bob
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No, the OMC motors were not variable speed and are three speed on each voltage setting (12/24V). I had 4 of those motors and none of them produced sonar interference although didn't have a SI unit with them.
The worst offender from what I can find, is the Motor Guide pre-digital variable speed. I just happen to have one of those and the interference is only on the 455 khz SI :(
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The "save myself some money" statement should be clarified here.....
When you buy a HB unit...HB will stand by their product...and IF you have interference problems AFTER you purchase a HB unit...HB will send you the interference kit at no charge to make you a satisfied customer.....(at least they did for me)...
That's why HB rocks...they stand behind their product until you are satisfied.....
I would say wait on the interference kit and see what happens...then call HB "IF" you have interference problems....
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Thanks for the fast replies.
Sounds like I will be fine. Yes, the TR is an old 3 speed, and I do have it wired to it's own battery with wires going up the opposite side of the boat that the wires for the 798ci will go.
I ordered the 798ci Combo and accessories today. Can't wait for the brown truck!
Thanks again guys!
Chip
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I have a HB 997 on A Minnkota Maxium 52 lb.trust 24 volt older motor . I have no interference
so far. Gary
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Trolling motor interference can still occur. I have recently attributed a vertical bar to appear on my 998 when the trolling motor in engaged. The trolling motor is on a separate electrical circuit/batteries and the locator is connected to the starting battery. The locator does have an inline choke on the power cable. I suspect there is interference induced into the transducer cable from the motor at the junction where the transducer cable follows along side the trolling motor housing.
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One other thing you should be aware of is you may need to get a transducer shield for transducer and the people at transducer shield also made a special bracket for me so it would mount to Evinrude trolling motor you dont have much room from the skag of trolling motor to the front of trolling motor.
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If you have trolling motor interference on your bow mounted side imaging unit, copy/paste the link below to your browser and follow the instructions. If you still have it, contact Humminbird to purchase a trolling motor choke!
http://www.humminbird.com/FAQ.aspx?ContentId=1849 (http://www.humminbird.com/FAQ.aspx?ContentId=1849)
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12? 24? 36? Trolling motor bow left, and TM Jack right? Consoles demise when they run the TM power to the right. Are the bow power cables grounded in any way with the console circuitry? Recharging TM batteries from the outboard? Try a main engine engine disconnect who know:) Good Luck see yaz out thar:)