Rado elec.ign noise - Off-Road Forums & Discussion Groups
Jeep-Short Wheelbase All discussion of short wheelbase Jeeps: CJ, TJ, YJ and JK

 
LinkBack Thread Tools Display Modes
post #1 of (permalink) Old 06-13-2000, 05:12 PM
**DONOTDELETE**
Guest
 
Posts: n/a
Rado elec.ign noise

First of all,i have the antenna correct now to my onboard police scanner,but i have a lot of electrical noise from the ignition,i will be buying a inline noise filter soon as well,but my question is,is there any place more noise free to connect to on a vehicle,somewhere where i would have the least noise to start with? side note "have a lot more noise after the TFI coil went in as well.And i am using condenser and new 8MM wires and resister plugs ,any idea's on that? TIA 4 N E info

Sponsored Links
Advertisement
 
post #2 of (permalink) Old 06-13-2000, 07:10 PM
Enthusiast
 
Join Date: Sep 1999
Location: Des Moines, IA
Posts: 370
Thanks: 0
Thanked 0 Times in 0 Posts
 
Re: Rado elec.ign noise

My ignition upgrade resulted in some radio interference too. I installed Jacobs wires and a Jacobs can type coil with Champion truck plugs gapped to .050. If I'm sitting in the open, it's OK, but when I get close to a building the interference seems to be reflected back. The only thing I've done to try to fix it is verify that the coil is grounded good.

jerry

jerry is offline  
post #3 of (permalink) Old 06-13-2000, 07:53 PM
**DONOTDELETE**
Guest
 
Posts: n/a
Re: Rado elec.ign noise

I think my noise now is coming the 12 volt feed,i think...I just thought maybe someone knew the best place to feed a radio from to start with.

Sponsored Links
Advertisement
 
post #4 of (permalink) Old 06-14-2000, 01:49 PM
**DONOTDELETE**
Guest
 
Posts: n/a
Re: Rado elec.ign noise

CORRECTIONS - SORRY FOR ANY CONFUSION

I assume that the noise is coming through the speaker of your AM/FM radio and/or the police scanner. This type of noise is generated from high frequencies associated with ignition systems. I noise filter is a good solution.

Basically, there are two types of ways to get rid of noise
1) Capacitive impedance in parallel (from 12 volt to ground) with the device
- This means a capacitor connected from the 12 volt source of the device to ground
A Capacitors look like an open switch to DC voltage and allow current to pass as the frequency gets higher.

2) inductive impedance in series (like a fuse - inline with the power wire) with the device
- This means a inductor connected in-line with the 12 volt source to the
Inductors look like a wire to DC voltage and resist current flow as the freguency gets higher


The best would be a combination of the two. There are many electronic supply houses and catalogs that can supply these types of noise suppressors.

I have attached a drawing that may help.

Feel free to email me direct

[email protected]

O|||||O
[img]/wwwthreads_images/icons/crazy.gif[/img] A conclusion is simply the place where you got tired of thinking. [img]/wwwthreads_images/icons/tongue.gif[/img]
Attached Images
File Type: jpg 9-151823-cap_ind.jpg (28.6 KB, 0 views)
post #5 of (permalink) Old 06-14-2000, 02:01 PM
**DONOTDELETE**
Guest
 
Posts: n/a
Re: Rado elec.ign noise

Filters are a good idea - for some systems they are a must. Good grounds are very, very, very important. We used to try to isolate the source of the interference - it is easy to do. Just take an old antenna and hook it up to a cheap AM radio (the radio must not be connected to the vehicle). Use the antenna as a "snooper" and you will hear the problem areas through the AM radio as it passes over. Good luck and did I mention it is very, very, very important to have good grounds throughout the Jeep....

Depewtee '78 CJ-5 (for sale)
'90 YJ (still in one piece)
post #6 of (permalink) Old 06-14-2000, 02:39 PM
**DONOTDELETE**
Guest
 
Posts: n/a
Re: Rado elec.ign noise

Nice picture of a low pass filter CJ8_Keith! Your pic was right but the words inductive and capactive, were reversed in you explaination if you don't mind me correcting the typo. The decoupling cap would go between 12v and a ground (in parallel) to short high frequency noise to ground, and the inductive load would go in series like a fuse to supress high frequencies through the +12 line into the radio.
Back to the original question, just try taking the power right off the battery terminals. Throw a fuse in the positive line, and run the two wires as far from the engine as possible and keep them right next to each other (twisted together if you're really feeling energetic) to decrease the loop area, (electromagnetic fields passing through a loop of wire causes noise current to flow in the wire) and also when they're together like that, noise coupling onto the + wire will also couple onto the - wire, hopefully partially cancelling out the noise that gets transmitted to the speaker. Then you can also try putting a nosie filter you can buy at most radio or electrical shops in the lines too. Good luck man!



Mike
Tucson, Arizona
post #7 of (permalink) Old 06-14-2000, 03:04 PM
**DONOTDELETE**
Guest
 
Posts: n/a
Re: Rado elec.ign noise

vanfleet - Thanks for the correction. SORRY FOR ANY CONFUSION.

You are very perceptive to see a low pass filter. Sounds like I am back in Electronics 101

o|||||o
[img]/wwwthreads_images/icons/crazy.gif[/img] A conclusion is simply the place where you got tired of thinking. [img]/wwwthreads_images/icons/tongue.gif[/img]
http://keith.cj8.tripod.com
[email protected]
post #8 of (permalink) Old 06-14-2000, 07:50 PM
**DONOTDELETE**
Guest
 
Posts: n/a
Re: Rado elec.ign noise,thanks all-No txt

.

post #9 of (permalink) Old 06-14-2000, 08:13 PM
**DONOTDELETE**
Guest
 
Posts: n/a
Re: Rado elec.ign noise

Make sure your ground wires do not parallel a power wire. I think you may be able to pass acrost a power wire, but only if it is at a 90 degree angle. The Ground should be as short as possible. Hope this helps.

J just
E mpty
E very
P ocket!!

'86 Cj-7 33x12x15" BFG 2.5" Rancho 258 T-176 Almost EVERYthing Rebuilt or Replaced
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Off-Road Forums & Discussion Groups forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome