Noise suppression

Diamond Blade

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Have searched through this forum, but I am still looking for some answers on the above subject.
My mates and I used to have the Intaride systems, but gradually progressed to Motorola GP360 radios on the PMR frequencies, through Autocom systems. The radios are ex Police stock and with a 4 watt output work really well. But the problem most of us have is the background noise/interference. I say most of us, because one or two seem to have no trouble at all.
Naturally, we all use different bikes.
I seemed to be in that latter catagory, with little background noise, until a few weeks ago when my transmissions became terrible with a high pitched sound drowning out the words.
Up until now, I ran my Autocom and radio power leads through a Centech auxilliary fusebox.
I tried going back to basics and a direct feed and earth from the battery, and its is clear until the engine is running. I tried cleaning all interface connections, and replaced the lead that connects the radio to the Autocom system, as it seemed loose at the radio connection end. None of this has helped, as the noise does not rise with the revs, but is constant.
My question really are;

Does some kind of shielded power cable, ie a kinda co-axial cable between the battery and the radio make any difference?
Also, does anyone bother with a noise suppressor nowadays - they seem awful scarce on the ground if they are necessary for bike comms?

We spoke with Autocom, and they suggested that we need another part, number 2437, a relay of sorts which takes its feed from the power source, ie the tail light, before supplying power to the radio. They were a bit cagey on whether this would solve our background interference noise.
This really is frustrating, especially when you watch bikers on telly, such as Hairy Bikers and McGregor/Boorman having crystal clear comms.
I'd be really interested to hear if anyone has solved this problem.
 
you could try a sheilded cable that would stop the conductor acting as an antenna for interfernece
i would take the -ve from the battery
i took my feed from the fuse box (r1100gs) used a piggy back fuse i think it was the fuse from the riders dispay etc

and conect shielding to ground
that might help

1 am sure someone will be along soon and help you out
 
How do you power your Centech?

My Centech is powered from a relay switched source direct from the battery (so it is off when the ignition is off). All electrical items (including Zumo and Autocom) are wired through the Centech and I have never had any ground loop problems or had to resort to shielded cables.

tom
 
Have searched through this forum, but I am still looking for some answers on the above subject.
My mates and I used to have the Intaride systems, but gradually progressed to Motorola GP360 radios on the PMR frequencies, through Autocom systems. The radios are ex Police stock and with a 4 watt output work really well. But the problem most of us have is the background noise/interference. I say most of us, because one or two seem to have no trouble at all.
Naturally, we all use different bikes.
I seemed to be in that latter catagory, with little background noise, until a few weeks ago when my transmissions became terrible with a high pitched sound drowning out the words.
Up until now, I ran my Autocom and radio power leads through a Centech auxilliary fusebox.
I tried going back to basics and a direct feed and earth from the battery, and its is clear until the engine is running. I tried cleaning all interface connections, and replaced the lead that connects the radio to the Autocom system, as it seemed loose at the radio connection end. None of this has helped, as the noise does not rise with the revs, but is constant.
My question really are;

Does some kind of shielded power cable, ie a kinda co-axial cable between the battery and the radio make any difference?
Also, does anyone bother with a noise suppressor nowadays - they seem awful scarce on the ground if they are necessary for bike comms?

We spoke with Autocom, and they suggested that we need another part, number 2437, a relay of sorts which takes its feed from the power source, ie the tail light, before supplying power to the radio. They were a bit cagey on whether this would solve our background interference noise.
This really is frustrating, especially when you watch bikers on telly, such as Hairy Bikers and McGregor/Boorman having crystal clear comms.
I'd be really interested to hear if anyone has solved this problem.

If you are still getting the noise when connected directly to the battery then a 2437 will not help. You might need a 2439 power filter.

Remove all connections to leave just the intercom in operation. Start engine - do you still get interference?

Do you get interference if the Autocom is wired to a different battery?

Could it be that something (a coil pack with integral suppressor) is failing causing this problem to develop quite suddenly?

HTH,

John
 
A couple of questions and things to check............

Does the high pitch whine interference you describe change in pitch with engine revs? If so, the problem is likely to be alternator / regulator related and within that the most likely cause are poor connections. So check all the charging circuit connections, including earth/frame and battery, clean and remake them.

If the high pitch is actually more of a crackle related to engine revs, the problem is likely to be on the ignition side of things and in this case, shielded cables may be the answer

The most stable source of power to use for ancilliary items on a bike is by direct connection to the battery (short of a sub regulated supply) but if the battery is poor, even the voltage here will fluctuate and can cause the problems you describe.
 
Sorry to dig up a old thread but I have exactly the same problem and could do with a resolve or at least some advice.

Heres the strange thing, I have nearly exactly the same setup.

1150GSA on a 03,
centech fuse panel,
active rider kit 200
interface lead to a bike 2 bike radio which is also bike powered.

With the engine off no noise.

I can hear the audio through the autocom at low revs and it goes inaudible in the autocom.

On the radio I'm told that the sound is audible through the whole rev range but is worst at low revs where its particularily annoying.

I have fitted ferrite rings at various intersections throughout the bike comms and autocom and power to radio too.

Any advice?
 


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