J&M CB Noise Issue - Frame Ground

jfheilman

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I have a 2007 ST1300A with GPS, Autcom Super Pro AVI. A year or so ago (I know a long time) I had to have some body work done (hit a deer). Anyway after I got the bike back, there J&M CB, when turned on, added substantial noise to the Autocom audio. One suggestion, from here, was that I had the J&M Intercom volume turned up (turns out I did). Lowering it to minimum did reduce the noise but not to where it was before the maintenance.

I am finally getting around to trying to resolve the issue totally.

I called J&M to see if I could get some additional clues on where to look. They suggested that I check the ground and stated that it had to be a "frame" ground.

Power is supplied to the units via a Centech AP-1 Auxiliary Fuse Panel. The cabling for the J&M is routed under the plastic so I have not traced it all the way from the Autocom or the fuse panel.

My questions are:

Is the battery negative terminal connected to the frame in some location and if so, where is that connection made?

I thought I'd make a troubleshooting plan before I start takin pieces parts off the bike.

Thanks.
 
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jfheilman

jfheilman

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Is the CB audio connected to the Autocom audio?
Did you try turning up the Squelch control on the CB ? ....
The CB is connected to the Autocom Aux Input (5 pin DIN)

Yes the squelch is all the way up. If I lower it I do get the normal AM background noise.

And, of course, when I unplug the interface, the noise goes away. What I should do is try and tie in my own earphones to the J&M direct and verify the noise is coming directly via the J&M system.

Oh, one more thing, if I thump on the J&M unit, I can hear it in the earphones. I think that is called an audio phonic reaction .
 

ST Gui

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jfheilman said:
Is the battery negative terminal connected to the frame in some location and if so, where is that connection made?
I don't know where the other end of the negative battery cable is connected.

Since the gear worked satisfactorily before your collision and didn't after it came back from the shop some possibilities come to mind:

•the CB and/or the Autocom were damaged internally
•the shop miss-wired your gear
•the shop rerouted some wiring allowing the Autocom to pick up noise.
•the shop missed damage to the wiring

What kind of noise are you hearing? Having electrical devices grounded to too many different locations can cause ground loops which can result in hum or buzzing. Some things like incandescent lights can be grounded anywhere (there's a good ground of course). Electronics should be grounded at one central point if possible.

Check to see that power cables aren't routed along side of or at least not bundled with input cables. Check all connections to make sure they're where they're supposed to be and in good shape. Is any of the wiring shielded? Make sure it's not damaged (torn outer sheathing) and properly grounded.
 
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jfheilman

jfheilman

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The kind of noise I am hearing is much like normal AM Radio static but the squelch is off. I mean I can turn it up enough to get the real AM noise but when turned all the way down its just what I would call white noise. Its very low level and music will almost cover it up.

One strange thing is that if the bike has been sitting for a day or so and I go out and turn the bike on ACC and then turn the J&M CB on, the noise is not there right away but sort of pops in a few seconds (maybe 5 or 10 seconds) later.

From then on, the noise will always be there.

It is very low level and I suspect the only reason I can hear it is I am using in the ear speakers (AKA earphones). But it was not there before the maintenance done by the dealer.

And that could be a coincidence.
 

jfheath

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Not quite your setup, but close enough. I have a satnav connected to an autocom super pro avi with rider and pillion. I also have a 2 way radio plugged in to the 5 pin lead from the autocom. I have an isolated lead to connect the audio in and out from the satnav to the autocom. Autocom is in the rear cowl.

I connect the mobile phone to the satnav by bluetooth. Music / instructions and phone call are all routed to the autocom. Voice to the phone is routed back to the satnav.

Power leads and audio leads are all routed together. I tape these over the top of the airbox to prevent interference from the coils and the HT leads. Straight over the middle works best.
I did wrap them in aluminium foil with a wire to earth to screen them further, when i first installed it, but this proved to be unnecessary.

Dodgy connections at the mini jack plugs can cause issues

Check the mics. If they have been wet, and have been allowed to dry slowly, they can grow small crystals which make them less resposive and will create hiss and hum when they are activated by noise - speech or wind. I always carry two spares with me as the only time they ever fail is when we are using them on a trip ! The mics should be dried on / near a radiator so that crystals have less chance to form. Better still if they dont get wet - but they are so close to your mouth .....

Check the noise sensor position - normally fitted in the helmet to pick up outside noise so that the autocom can turn up the volume as speed / wind noise increases.

Check the vox setting on the autocom is set so that it only activates when you talk.

Check the DIN connector on the cables. These can cause interference if they get water in them.

You can find out if it is a headset / cable issue by testing with the pillion set if you have one, without the rider set plugged in.

Some people have tried the old hi-fi trick of removing the earth from the autocom, to remove the earth loop hum that can be create d. By the connection of the screened audio leads. However, i find that others that have done this broadcast loud ht lead interference to other bikers. I never have problems with that, but the isolation lead sorts that out. I think it couples the audio with circuitry that utilises LED light and receptors rather than a copper wire. Expensive, but it works. Its a normal lead with a small in- line sealed bulge. If you are interested i'll find the part number, but i am on the ipad version 1 at present, and it is difficult enough just typing, or using capital letters.

I have known the stranded wires in the headset break inside their insulating sleeve. Especially where the two headphones and the mouthpiece cables join together near the DIN plug. This starts off as a feint radio like interference. It then becomes an annoying crackle, and just before it fails it will set off fireworks in your ear as it connects and disconnects as the broken strands brush their ends together.

Some of these faults are diificult to isolate without replacing parts with new - but I reckon its always worth having a spare set of everything on a trip, so it is not an unnecessary expense. I keep them in a sealed ploythene bag in the top box.

Which reminds me - i need some replacements before the spring.
 
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okmurdog

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Do you have the rider-passenger J&M?...If so, have you checked the setting of the intercom volume on the J&M? If the intercom volume is turned up, you’ll receive noise similar to your description. The intercom volume is found by pulling outward on the on/off knob.
 
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jfheilman

jfheilman

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Do you have the rider-passenger J&M?...If so, have you checked the setting of the intercom volume on the J&M? If the intercom volume is turned up, you’ll receive noise similar to your description. The intercom volume is found by pulling outward on the on/off knob.
Yes and yes. It was a source of some of the noise but it is now minimized. It seems to be related to my "interface".

I just tried it again (after looking at the interface connections) and when you initially turn on the unit (after being off for about 24 hours), all is well, very quiet. After about five seconds, the low level noise begins.

Turn the unit off, wait 10 seconds, turn on, no delay in noise.

What I can't find at this moment, is the schematic for my interface between the J&M system and the autocom. I built the interface just after I got the bike and installed the equipment and it has worked flawlessly until the maintenance.

The interface is not that complicated but I would still like to make sure its set up as it was when I first installed it.

One more thing I will check, which is different than the way it was at first. I am using earphones only via an interface with the Autocom system. I will try it again tomorrow with the normal autocom cables and mikes. It might be something in the earphone interface.
 
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jfheilman

jfheilman

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John,

I want to thank you for your detailed post. I will read it again and see what might affect my system operation.

I do have a question about Autocom though. The dealer I was working with here in the states, Rocketmoto, is out of business. I see that I can purchase Autocom supplies from the UK. Do you have a suggested supplier?

I have spares for most everything but might need to stock up as your suggest. Seems wired is going out of style but the bluetooth interfaces I have seen don't have the battery life of the stability of a "wired" system and its only one wire :)

Thanks Jim
 
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jfheath

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I do have a question about Autocom though. The dealer I was working with here in the states, Rocketmoto, is out of business. I see that I can purchase Autocom supplies from the UK. Do you have a suggested supplier?
You can deal with Autocom themselves, but I now prefer Chainspeed. They have a 'contact us' email address too.

Why ? Well I discovered a very helpful chap, Sam, at Chainspeed, that not only used to put the Autocom stuff together in their early days, but he knows from first hand experience the issues that they present. You get a very clear impression when talking to him that he has encountered the problems for himself and has worked out what the solution is.

The isolation connector that I was on about is part # 4066 in the chainspeed catalogue. Specifically for use with the Zumos and audio which allows the use of a phone. It's expensive, but I never have anything but clear communications - except when my Mic has got wet ! They do a cheaper cable which doesn't allow phone conversations - but everything is very well described on their website.

All of their accessory parts are very well described and they sell Bluetooth stuff as well. Tell them what you want to be able to do, what you have now, what problem you are having, I am sure they will be able to help.

You have to be careful of the power connection on one of the Autocom jack sockets. Get your instructions out. I can't remember which one it is - its a 4 pole connector, but plugging the wrong thing into it can send 12v down the lead to an unsuspecting audio circuit. I don't use it, and whichever hole it is, mine is taped over. Sorry, I cant remember the details, I rarely touch the autocom - it just sits in the rear cowl in its plastic bag, doing its job.

If you are intending to use a mobile phone, mention this to them as well - modern digital autocoms apparently are better matched to modern phones. The Super Pro Avi is an analogue device, and the volume from the motorbike to the caller at the other end can sometimes be a tad quiet. Weirdly, not all of the time, but just occasionally, I have had to shout. Volume level coming in is Ok though. Sam knows all about this too - I had a lengthy conversation with him about the pros and cons when I bought my current SuperPro Avi.



I have spares for most everything but might need to stock up as your suggest. Seems wired is going out of style but the bluetooth interfaces I have seen don't have the battery life of the stability of a "wired" system and its only one wire
Personally, I agree. I'm happy to use the phone to Zumo as a Bluetooth connection - that seems to be entirely reliable, but my limited dabbling with Bluetooth to the autocom (via a dongle) has been less than successful. With our wired arrangement, we can both talk over the bike to bike intercom; talk to each other; both talk over the phone; both hear the Zumo instruction; both hear the music. (Except the volume for pillion can be turned right down for audio from the Zumo if required).

I discovered that Spanish law no prohibits any form of communication for motorcyclists, and that includes satnav instructions and rider / pillion communication. I reckon that is a safety hazard - I rely on my pillion to remind me to ride on the 'wrong' side of the road after filling up - always an issue for us Brits on the continent. But that is their law, and riders with leads to their helmets are easy to spot !
 
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jfheath

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I do have a question about Autocom though. The dealer I was working with here in the states, Rocketmoto, is out of business. I see that I can purchase Autocom supplies from the UK. Do you have a suggested supplier?
You can deal with Autocom themselves, but I now prefer Chainspeed. They have a 'contact us' email address too.

Why ? Well I discovered a very helpful chap, Sam, at Chainspeed, that not only used to put the Autocom stuff together in their early days, but he knows from first hand experience the issues that they present. You get a very clear impression when talking to him that he has encountered the problems for himself and has worked out what the solution is.

The isolation connector that I was on about is part # 4066 in the chainspeed catalogue. Specifically for use with the Zumos and audio which allows the use of a phone. It's expensive, but I never have anything but clear communications - except when my Mic has got wet !

All of their accessory parts are very well described and they sell Bluetooth stuff as well. Tell them what you want to be able to do, what you have now, what problem you are having, I am sure they will be able to help.

If you are intending to use a mobile phone, mention this to them as well - modern digital autocoms apparently are better matched to modern phones. The Super Pro Avi is an analogue device, and the volume from the motorbike to the caller at the other end can sometimes be a tad quiet. Weirdly, not all of the time, but just occasionally, I have had to shout. Volume level coming in is Ok though. Sam knows all about this too - I had a lengthy conversation with him about the pros and cons when I bought my current SuperPro Avi.



I have spares for most everything but might need to stock up as your suggest. Seems wired is going out of style but the bluetooth interfaces I have seen don't have the battery life of the stability of a "wired" system and its only one wire
Personally, I agree. I'm happy to use the phone to Zumo as a Bluetooth connection - that seems to be entirely reliable, but my limited dabbling with Bluetooth to the autocom (via a dongle) has been less than successful. With our wired arrangement, we can both talk over the bike to bike intercom; talk to each other; both talk over the phone; both hear the Zumo instruction; both hear the music. (Except the volume for pillion can be turned right down for audio from the Zumo if required).

I discovered that Spanish law no prohibits any form of communication for motorcyclists, and that includes satnav instructions and rider / pillion communication. I reckon that is a safety hazard - I rely on my pillion to remind me to ride on the 'wrong' side of the road after filling up - always an issue for us Brits on the continent. But that is their law, and riders with leads to their helmets are easy to spot !
 
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jfheilman

jfheilman

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John,

Thanks again for the detailed response. I have seen Chainspeed before but never dealt with them. Now have them bookmarked.

If you ever get to the states, maybe we can have a beer or some bangers and mash.

I have had some of the same issues with the bluetooth dongle. But have used it for awhile and then, I forget why, I shelved it.

I have my phone blue toothed to the Garmin and now i have added a cable for direct audio. Funny thing, I did not think about how it would work if I got a phone call while it was hard wired to the autocom.

Thanks again for the info.

Jim
 

jfheath

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John,

Thanks again for the detailed response. I have seen Chainspeed before but never dealt with them. Now have them bookmarked.
If you ever get to the states, maybe we can have a beer or some bangers and mash.

I have had some of the same issues with the bluetooth dongle. But have used it for awhile and then, I forget why, I shelved it.

Jim
That would be nice - although I have no plans in the foreseeable future.

I can guess why you shelved it if it is the same model as mine - it gives a louder than necessary, ear-piercing beep every time that it connects - and because it doesn't keep the connection very well, this tends to happen a lot when riding. I could just about cope with it, but the noise also seems to be accompanied by a sudden pain in my kidneys and I hear a noise in my earpiece which sounds something like 'Do we have to have that ********* thing turned on'.

There will be a whole section of the motorcycling fraternity who have a similar story.
They are easily recognised - the opening conversation goes something like this:

"Hi there - Oh - have you hurt your back ?"
"What was that you say ?"
"Ah, you must have a Bluetooth dongle fitted."

Fortunately, the the Zumo 590 series Bluetooth I have found to be very reliable. ie it has never lost the connection with my phone.
 
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jfheilman

jfheilman

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I have the Garmin 600 series and my phone always connects.

I also just added an isolated stereo lead I found in my box of Autocom stuff. I now use it to connect the phone directly to Autocom for listening to audio programs I can't get any other way.

Just for the record, all the tests I did with the J&M were made with the engine off and the bike ignition switch in the ACC position.

I tested it on the road yesterday and the noise is the same.

Again, the first time you start the bike and then turn on the J&M, there is no noise and then it builds to a low lever static. Turn it off and wait five or ten seconds and turn it back on the noise is there instantaneously.
 
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From an electrical perspective, these systems need to be tied to a single point ground, on the frame. Else their can be multiple ground loops which can cause noise. Also make sure there aren’t any one side unconnected wires that could act as antennas. And if cables are going near high voltage ignition components, shielded cabling is best where each end needs to be tied to frame ground.

point being, daisy chaining grounds can be not only noisy, but a fire hazard. See reference:
https://www.w8ji.com/negative_lead_to_battery.htm

and where 2-way radios and other high current devices are concerned, never use existing harness or accessory wiring. This results in the most common source of fires:
http://www.k0bg.com/wiring.html

353E48F5-EB3B-48E5-816B-CBEE90A6070B.jpeg2340A270-CECB-48D6-82F4-7D1FFE990D63.jpeg
 
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jfheilman

jfheilman

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I know its been awhile since I started this thread but, yesterday, I took off the left side plastic to run a new cable for my Adaptiv radar detector. While I am in there I will be looking at the J&M connections.

I am also having an issue with the J&M's sensitivity, so I will be doing some power and SWR checks. Along with looking at the audio again.
 

larryg

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This may be totally off base, but do you have HID headlights ?
When I did I had severe noise in the CB, which really reduced the CB's sensitivity.
Removed the HID lights, and installed LED's. Noise completely gone.
 
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