Alternator Whine Filter..

Is what your hearing coming thru your ext speaker or stereo speakers ?
The "old" chokes worked on the analog,we are digital now and the chokes do not work like they used to.

 

DIGITAL CB RADIOS

EVERY Regency FM 2 way radio i ever ran in the car would wine like hell UNTIL I put a filter in line ...

 

AGAIN the NEED to raise your hand ?
Your special,and we'll just leave it at that . . . . .

All the old mobile 23's would do the same,SAME corrective grounding measures
applied then as they do now.
Werent no "ECM's" or higher volt alt's back then,we still managed without inline clutter.
Go Figure>....

 

Is your extension speaker powered or amplified?
What exact kind of model of extension speaker is it?
not a "PA horn", right?
Is there any whine from the radio's own speaker no matter how faint?

If the ext. speaker is an 'amplified' or 'powered' type, run off 12V, and the radio speaker does not emit this whine, then the powered extension speaker could be the source of this noise. A filter will work on a "powered" or "amplified" extension speaker. Such speakers have a sensitive amplifier built in and run on 12V, so they can either pickup the whine from the DC power, or they can greatly amplify the whine from the radio to the point it is annoying. That is why I asked about the speaker. If using an amplified speaker, the ground or (-) wire from the amplified speaker and the CB should connect to the same place, and preferably be as short as possible, 1-2' at most.

Some people do better with the radio (-) lead to chassis ground, some with it to the battery (-) post. I use the + and - battery posts in my truck but in my old car the fusebox and ground gave cleaner power than the battery or the cigar lighter connection. I have also had success taking power from the same place as the car stereo is powered, the input to its fuse in the fuse box.

Here are a couple store-bought filters, may or may not do what you want. Also, nearly all CB radios have a simple internal "LC" filter built into them and should not pick up alternator whine unless something is wrong. Whine is a PITA to find in some cases.

This filter is way overkill # $59.95, but it should do the job:
The MFJ-1142 is a compact filtered DC outlet. It connects between your your transceiver and DC power supply. It reduces RFI, hash, noise transients, noise generated by motors, alternators and fuel pump whine. It works with Power window motor noise, other motor noise and other RF transmitters. For 12vdc and 24vdc DC power sources. Has both heavy-duty 5 way binding posts and Anderson power Pole connectors for input and output. Dimensions 3"W 2-3/4 H and 4-3/4 D
http://www.hamradio.com/detail.cfm?pid=H0-009713

Less overkill:
$29.99
Powerwerx LF-1-OEM
13.8V 20A LINE FILTER WITH OEM CONNECTORS
DC Noise Filter (Commercial Grade) reduces alternator whine in transmit and receive operation in many 2-way radios. The current capacity is 20 Amps maximum and 16 amps continuous service. This cable includes OEM-T in-line connectors.
http://www.hamradio.com/detail.cfm?pid=H0-010380

They sell less expensive alternator whine chokes and filters (filter is a choke with a capacitor, "LC") in CB shops, etc. which are rated more for 5 or 10 amps, like a regular car stereo would use.

Alternately you can make an filter yourself if you can find the parts as shown. That is what is inside the $29.95 special. It can be expensive to buy separate parts new but sometimes a good CB shop junkbox will yield what you need and the ones you might cobble up work just like any storebought unit to eliminate alternator whine. I mainly show the hookup so people can see what these things are and how they are not mysterious but just a couple of simple parts.