Whine in Audio on Handeld CB

[FJRandy]

I've got all my equipment (Autocom & CB) grounded to the Blue Sea and the Blue Sea ground running directly to the battery. I'm still getting annoying whine in my CB - both sending and receiving. I'm going to try running the power line through some braided tin covered copper shielding (and I'll ground the shielding) and report back on whether it helped or not.

Knock yerself out, but you're wasting your time. The noise IS the spark plugs you're hearing, and it's somewhere between the ground reference on the CB mic/headset output and the Autocom input. Alternator whine is a "whistle" that rises and falls with the rpm's. Spark plug noise is a popping scratchy noise that also rises and falls with rpm.

The problem is difficult to get rid of if you run an Autocom. I wanted to make a double RF choke jumper setup to go inline with the double Midland plug, but I decided to live with it. Lazy? You bet! Actually it's minimal enough to live with.

 

[FuzzyRider]

I've got all my equipment (Autocom & CB) grounded to the Blue Sea and the Blue Sea ground running directly to the battery. I'm still getting annoying whine in my CB - both sending and receiving. I'm going to try running the power line through some braided tin covered copper shielding (and I'll ground the shielding) and report back on whether it helped or not.

Knock yerself out, but you're wasting your time. The noise IS the spark plugs you're hearing, and it's somewhere between the ground reference on the CB mic/headset output and the Autocom input. Alternator whine is a "whistle" that rises and falls with the rpm's. Spark plug noise is a popping scratchy noise that also rises and falls with rpm.

The problem is difficult to get rid of if you run an Autocom. I wanted to make a double RF choke jumper setup to go inline with the double Midland plug, but I decided to live with it. Lazy? You bet! Actually it's minimal enough to live with.

Randy, I've wasted time on worse projects. You're right, it's a popping scratchy noise that rises with RPM. Hey, if I can reduce the interference I'll be happy - I don't need to get rid of it entirely.

 

[FuzzyRider]

Holy thread-revival!

OK, so here's my current (both time and voltage over resistance) setup and results:

I have power and ground wires running from a relay next to the battery through braided shielding to the inputs of a Pyramid 35 Amp noise filter. The wires and shielding are run in a wire loom routed under the tank. I soldered/brazed a ground wire on the shielding and connected it to the ground wire for the Blue Sea. The noise filter and Blue Sea are mounted under the rider's seat.

The power and ground wires for the Autocomm (located under the passenger seat) are run in a loom without shielding since the area from the rider's seat to the passenger's seat is far enough away from the coils/spark plugs.

The power/ground wires for the CB run from the Blue Sea and are routed under the tank and up the back of the handlebars. These wires do run through the braided shielding and are enclosed in a wire loom. This braided shielding also has a ground wire brazed to it and run to ground.

Finally my 3mm audio cable runs through a grounded braided shield in a wire loom from my iPod (mounted in an Aquabox on the handlebars) under the tank to its destination at the Autocomm.

The results? The iPod is completely noise-free at all RPMs. The CB is as close to noise-free as possible. Friends that I ride with say they can hear an ever-so-slight hum when we communicate in a parking lot but they have to really be listening to hear it. When on the road the slight hum is completely covered by wind noise from speed. My comm and audio systems have never sounded so good - the empirical evidence is that the braided shielding made a HUGE improvement. Oh yeah, one more thing - even if not completely necessary I use a no ground plane CB antenna.