It has been requested that we have a sticky just for RF type interference with electronics. So this is the place to post your problems and cures for such type problems.
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It has been requested that we have a sticky just for RF type interference with electronics. So this is the place to post your problems and cures for such type problems.
Good idea Bill...
Let me get the links to these in here right at the first..
Trolling Motor Induced Sonar Interference
http://notjustfishing.com/MotoGuide.pdf
Here are a couple more references from Humminbird.
Humminbird: America
Humminbird: America
Call these folks about your ferrite core needs for RFI. They are the toroidal donut experts.
Toroid cores for amateur radio
RF interference after initial set-up. This noise was on SI & DI(455 & 800) with no noise on 2D.TD is mounted on TM
Attachment 75909
After re-routing my TD cable the noise still remained on 800kHZ but was clear on 455kHZ.
After installing the TMC-1 this is what I now have. Clear on 455 and very little on 800..I will live with this until I visit Tom..:)
I have no idea what the white horizontal line is on the DI..It shows up when I select 800kHz even with the TM unplugged.:confused:
Attachment 75910
I have been working on my TM, so I thought I would make this short video so someone might relate to what is going on with pwm as related to noise and speed of the TM.
You will see the noise spikes near the end of the video. I did some rough calculations of the noise frequencies present. The noise ranged between 1 megahertz down to 100 kilohertz. These noise frequencies fall in the band of the sonar transducer frequencies. (RF). That is why you see it on the screen. This is just a show and tell and does not cover all the noise sources of RF.
Hope it make sense to someone.
http://i188.photobucket.com/albums/z...h_PWMNoise.jpg
Wanted to add that the fundamental frequency of this PWM is 20Hz. So, what you see is a 20Hz modified square wave. When you run wide open, the bottom line goes straight, meaning a solid ground is supplied through the FET to the negative side brush of the motor so there would be no pulses, therefore no noise at WOT (kinda). The reason the pulse fundamental frequency is so low (20 Hz) is because at higher pulsed frequencies, you can actually hear the motor squeal like a pig. When you hear that "click" everytime you hit the foot switch, well, that is a 50 amp relay operating which places 12/24v to the positive motor brush. This is a coasting relay which prevents regenerative braking. In other words, the motor coasts to a stop instead of stopping suddenly. Electric choo choo trains use regenerative braking to slow down. Disc brakes don't work too good on choo choos.