Autocom noise filtering or lack thereof

[johnlt]

I have moved my autocom/zumo/V1/HID aux lights from my 06 GS Adventure where it worked great over to my new-to-me 07 RT. All functions properly but I am getting a lot more ignition noise and HID ballast noise in my audio. The SuperPro AVI has the negative power line direct to the battery so the hook-up is the same as it was on the GSA. Other than messing around with the wire/lead routing etc., is there anything else I can do to filter out the ignition and ballast noise I am getting.

[krussell]

Where is the positive lead connected?

 

On my RT, I had a lot of trouble until I went straight to the battery with the negative, and to the centech with the positive.

 

I also found routing cables down the left side of the bike to be quieter than the right side of the bike.

 

[Tom B]

Unplug ALL audio accessory leads from your Autocom main control box and you should find that your Autocom is working very well as a rider (or rider to passenger) system without any electrical noise.

 

Now if you plug just one Aux audio lead back in to you Autocom system at a time (making sure the other end is properly connected to the audio device) and try it you will discover which audio device or audio lead is picking up the electrical interference, and then we can look at ways to improve this.

 

The chances are that when you find which audio device or lead is picking up the electrical interference from the bike you will have to reposition it slightly further away from the noise.

 

Tom

 

[Whip]

Do ya use Ground Loop Isolators???

 

 

They help a bunch.

 

 

 

[johnlt]

Yep, got them on all the bike powered leads. My guess is that I just installed a "music lead" connected to the rear speaker pins of the radio and routed the wire fairly close to the alternator (not a lot of choice). I have to remove the tank to change it and I'm not in the mood to do that right now but the next time I have it apart, I'll check it out. I just wish Autocom had better shielding and noise isolation. It's not rocket science, it's just good EMI design practice....but it may not be the cheapest.

[Peter Parts]

I have only generic experience here, but Step One normally would be walk around the bike with the set and see if it picks up more noise in one place or the other... in which case it is directional radio waves in the ether rather than in the wires.

 

I gather you feel the problem is in the wires and that's much easier to deal with. As general good practice, I stick ferrite radio-frequency snubbers on wires here and there. These are cheap and available at computer parts stores and don't involve cutting any wires. Better is to use high-frequency filters made from little coils (to block) and little capacitors (to short) the offending gremlins.

 

As always, better to control noise at the source rather than at the receiver. There's no lead on the bike that needs to radiate in order to work. BMW uses shielding on some wires into the ECU on my model but is not consistent on this (the O2 wires are shielded only on the ECU side of the connector; go figure). Shielding itself might serve as a kind of filter too, both at the source and at the set.

 

The spark system RFI suppression depends on having resistor spark plugs. I wonder if these ever short into low- or non-resistor status after years of use? I love iridium plugs for my Oilhead but they seem to last forever, no kidding. Easy enough to check the resistance of a spark plug.

 

But make sure you don't need to do Step One.

 

Only 15 days left to the Toronto riding season this year.

[Tom B]

If you follow my suggestion above you will normally find that moving the audio lead, just an inch or so from the offending interference on the bike, it will normally cure any such problems, and for the benefit of other readers this is normally best done while doing the installation rather than refitting all the plastics and then finding out afterwards, per the recommendations in the instructions

 

I understand the point about wishing Autocom fitted better shielding and noise isolation, but the fact is we do use high quality screened leads, and connect the screening back through our systems to the bikes battery earth, however the problem is that parts of bikes are not design for audio leads to be put close to them, not even high quality shielded audio leads like ours, which is why we go to great lengths to share our experiences with others so that they know how to avoid such problems, and I suppose one could just as easily say, I wish bike manufactures made their bikes with less electrical interference to avoid such problems.

 

As johnit has discovered and pointed out for everyone’s benefit, it is much easier and less frustrating to test the system during installation and move any parts if required before discovering interference after refitting all the plastics.

 

Tom