ChrisRolleston
Registered user
Last Autumn I traded in my GS for an RT. I'd been running a battery powered Autocom PRO-7-SPORT and no sat-nav. On the RT I wanted to run both, bike-powered, and to use the sat-nav as an MP3-player as well as navigation. Rich told me what bits I needed and I gave them to the dealer who wired it up.
I'm using the BMW sat-nav brackets that bolt to the handlebar clamps and the Autocom is velcro'd in place in the box just under and behind the passenger seat at the other end of the bike.
Both the PRO-7-SPORT and the sat nav are wired to the rear power socket on the RT. They stripped some insulation from the live and return cables to the power socket about 6 inches from the socket and soldered the two Autocom power supply wires to them, then wrapped them with tape.
Then about half way between there and the Autocom box they stripped some insulation from the Autocom power supply cables and soldered in the sat-nav power supply wires (live and earth again) in the same way.
The audio lead from the sat nav is connected to the Autocom via an Autocom isolated music lead.
If I connect the sat-nav audio to the music socket on the Autocom I get good music quality and volume, but a background crackle which is especially noticeable and annoying if there's no music playing. Strangely, it seems to disappear when I apply either the front or rear brake.
If I connect the sat-nav to the Aux 2 socket there's no crackle (that I can hear anyway) but the music volume is lower and nothing like such good quality. Also the volume doesn't seem to reduce when we speak on the intercom.
The crackle doesn't stop if the sat-nav is switched off - you have to pull the fuse on its power supply or take the sat-nav off the cradle to get rid of it.
I don't see how it can be ground loop interference because the sat-nav is isolated from the Autocom using the recommended lead.
On the other hand the audio cable runs the length of the bike through what must be a pretty hostile environment from an interference point of view. Also they haven't connected either of the earth wires directly to the battery, as I think Autocom recommend.
And why does the crackle go away (or at least reduce to the point where I don't really notice it) when the brakes are on? Maybe that has something to do with making a circuit to ground through the brake light but how would that affect the Autocom?
It's a mystery. I'd really like to use the music socket if I can because the quality is so much better.
Help! Any ideas?
Chris
I'm using the BMW sat-nav brackets that bolt to the handlebar clamps and the Autocom is velcro'd in place in the box just under and behind the passenger seat at the other end of the bike.
Both the PRO-7-SPORT and the sat nav are wired to the rear power socket on the RT. They stripped some insulation from the live and return cables to the power socket about 6 inches from the socket and soldered the two Autocom power supply wires to them, then wrapped them with tape.
Then about half way between there and the Autocom box they stripped some insulation from the Autocom power supply cables and soldered in the sat-nav power supply wires (live and earth again) in the same way.
The audio lead from the sat nav is connected to the Autocom via an Autocom isolated music lead.
If I connect the sat-nav audio to the music socket on the Autocom I get good music quality and volume, but a background crackle which is especially noticeable and annoying if there's no music playing. Strangely, it seems to disappear when I apply either the front or rear brake.
If I connect the sat-nav to the Aux 2 socket there's no crackle (that I can hear anyway) but the music volume is lower and nothing like such good quality. Also the volume doesn't seem to reduce when we speak on the intercom.
The crackle doesn't stop if the sat-nav is switched off - you have to pull the fuse on its power supply or take the sat-nav off the cradle to get rid of it.
I don't see how it can be ground loop interference because the sat-nav is isolated from the Autocom using the recommended lead.
On the other hand the audio cable runs the length of the bike through what must be a pretty hostile environment from an interference point of view. Also they haven't connected either of the earth wires directly to the battery, as I think Autocom recommend.
And why does the crackle go away (or at least reduce to the point where I don't really notice it) when the brakes are on? Maybe that has something to do with making a circuit to ground through the brake light but how would that affect the Autocom?
It's a mystery. I'd really like to use the music socket if I can because the quality is so much better.
Help! Any ideas?
Chris
