Humminbird side scan and Pro tour troll motor

This topic has 9 replies, 5 voices, and was last updated 17 years, 12 months ago by oldtimer57.

Viewing 10 posts - 1 through 10 (of 10 total)

Author

Posts
June 19, 2008 at 11:01 pm #403650

steeler34
Participant

I just replaced an older Motorguide witha Pro tour 82 pound unit. The transducer for the 797 is on the troll motor (same as the last install). Now, when I run the troll motor, the side scan image goes white. A little whter with more power, little less with less power. It does it regardless of whether or not the motor is in the water or not. I tried it on 82 and 200 MHZ with no change. sonar is connected to the stating batteries as Humminbird suggests. Any help would be appreciated. Milton 04 Cougar, 225 Opti

June 19, 2008 at 11:08 pm #403653

Bass Cat Boats
Keymaster

It is interfering with the troller and we assume you have a MG troller and not an MK?

June 19, 2008 at 11:13 pm #403656

steeler34
Participant

I am not sure what a “troller” is. The transducer is mounted to the trolling motor head witha Humminbird bracket. the transducer wire is run up the shaft, and loosly ty wrapped to the steering cables to the screen that is mounted in the same location ans the old telefles circle graph (bit the dust) on the nose of the boat. The Troll motor is a Pro Tour cable steer, digital speed variable control Thanks MKG

June 20, 2008 at 12:53 am #403660

PhilAddison
Participant

I am not sure what a “troller” is Short for trolling motor.

June 20, 2008 at 2:02 am #403663

basschaser
Participant

PA – man of many words today? BCB is telling you that you that the troller is interfering with the graphs signal. I havent ever had any big problems with that but some stuff on the screen at times but nothing that has bugged me though. The only thing that I have heard that might help is to ground the cranking battery to the trolling battery (neg to neg) just one wire. There are others here who have fought the fight so I am sure you will get some better info but good luck. Judd Lasiter

June 20, 2008 at 2:11 am #403666

steeler34
Participant

Got it, I have played with it some more. The interferance goes away at full bypass. Hmmmmmmmmm . I will try jumping the neg to neg, but in the charging system, I think that is already there. Milton

June 20, 2008 at 2:23 am #403668

Bass Cat Boats
Keymaster

This is the model troling motor I have. 9BT42GAAF

June 20, 2008 at 2:32 am #403671

Bass Cat Boats
Keymaster

Full byp[ass eliminates the Digital signal that is conserving battery voltage. The interference is coming from the on an doff pulse of the “troller”. Grounding the bracket and shaft will help in some cases. Though you would have to come from the engine battery leads, which you can access on one of the lighted switches behind the panel. Otherwise contact HumminBirds tech line that was set up last year. They may have an answer. BCB

June 20, 2008 at 12:28 pm #403674

steeler34
Participant

Perfect, will try that today. What happened to cane poles and real worms? Now I have to learn about “doff Pulse and trollers” Thanks Milton

June 21, 2008 at 1:14 am #403676

oldtimer57
Participant

These things use “pulse width modulation”. Rather than trying to vary the voltage or limit the current as the old motors did with a big resistor (or a bank of them for different speed settings) they now modulate the power on and off. For a given unit of time, the power can be fully on, fully off, but nothing else. High speed would be power on for each “cycle”. Low speed might be power on for one cycle, off for 10. The problem is that turning the power on and off creates and collapses a magnetic field around the wiring. And that can be picked up by the depth finder when the depth finder frequency is some multiple of the on/off frequency. I first saw this on an early MK maximizer. Loved the motor although the shaft (back then) was steel and with no break-away it would bend in river current if you hit something. But I gave up on the transducer mounted on the motor itself because of the interference issue. There are lots of things to do to minimize interference, but very little that can eliminate it 100%. Good grounds. Chokes to absorb the ambient RF energy that appears in the wiring as the motor is pulsed. Etc. On my MK, I found that some speed settings were not bad, and some would just about wipe out the display on the finder. Newer finders are better at filtering, but this is a non-trivial issue. If you eliminate all the interference, you also eliminate a lot of small detail that appears to be interference noise… Personally I have been amazed that I could get away with a transducer hung right under the TM, because that is a normal motor with brushes that arc by nature, and all that RF noise somehow does not kill imaging as I would expect. I used one of the original Lowrance flashers when they first came out, and anything on the boat would send it into a frenzy of flashing at oddball depths around the scale… Now we have the new side-imaging stuff (admittedly with the transducer(s) mounted in the rear, and we get images clearer than what doctors used to get for x-rays 20 years ago… with all the stuff running in the boat as well…2008 Pantera Classic2014 Mercury Pro XS 200
Author

Posts

Viewing 10 posts - 1 through 10 (of 10 total)

You must be logged in to reply to this topic. Login Register