RadioReference on Facebook   RadioReference on Twitter   RadioReference Blog
 

Go Back   The RadioReference.com Forums > Topic Specific Forums > CB Radio Forum

CB Radio Forum Discussions regarding Citizens Band Radio (CB)

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
  #1 (permalink)  
Old 11-19-2012, 9:20 AM
topgun1986's Avatar
Member
  Premium Subscriber
Premium Subscriber
Amateur Radio Operator
Amateur Radio
 
Join Date: Sep 2012
Location: Southeastern Missouri
Posts: 127
Default CB voltage spike??

Finally got around to hooking up my Cobra 25 GTL WX cb radio in my 2009 Jeep wrangler this past weekend and have already ran into (2) problems.

Problem #1)
I have the cb POS and NEG hooked directly to my jeep battery, with a 2amp fuse placed in series with the POS up by the cb. Noticed driving down the road with the radio on or off, the cb gets like a voltage spike or surge, spiking the audio output and the light output. It lasts each time for literally a split second.
Even noticed last night in the garage, with the Jeep turned off, it would still do it. Seems to do it maybe once a minute if that; it seems sporadic at best. After realizing it would not stop, I unplugged the power supply from the CB. It is a fairly new battery, that reads 14.2V, not sure if that plays any part or not.

Problem#2)
Not really a major problem, but rather confusion. My jeep has an AUX output jack on the AM/FM in dash radio for ipods, etc. I got creative and plugged a cord from that AUX jack to my CB speaker output jack (on rear of CB), hoping I could listen to the CB audio this way over my Jeep factory speakers. With AUX cord unplugged, the audio on my CB sounds fine, with or without the Jeep cranked and running up and down the road does not seem to make a difference on the audio output from the CB speaker itself.
But I am getting some sort of "static" in my Jeep speakers when I try to run the CB speaker output (on rear of CB) through my Jeep AUX jack. Could I possibly put a filter of some type in line with this AUX cord or are my Jeep factory speakers no where near the impedance they need to be for my CB?

These problems may be obvious to some, so please keep in mind, I'm fairly new to radio hobby.
Thanks!
__________________
2011 Silverado - Icom IC2410A, Radio Shack Pro 106 scanner,
Shack- Icom IC2400A, Radio Shack Pro 197, Pro 163, Pro 2067, Cobra 29 LX
Reply With Quote
Sponsored links
  #2 (permalink)  
Old 11-19-2012, 3:10 PM
kb2vxa's Avatar
Completely Banned for the Greater Good
  Amateur Radio Operator
Amateur Radio
 
Join Date: Mar 2005
Location: Point Pleasant Beach, N.J.
Posts: 6,127
Default

I don't know what to tell you about the voltage spike, odd enough with the engine running but just plain weird with it off. Whatever it is it doesn't seem to be causing problems so I'd not worry about it. Oh and BTW battery terminal voltage is 12.6 no load and 14.2 while charging.

The placement of the fuse DOES worry me, it should be at the battery to protect the wiring. With no fuse to protect from an accidental short you'll get full battery current, about 500 amps for a split second through the wire before it melts possibly causing a fire in the engine compartment.

Speaker impedance has nothing to do with the static in the stereo speakers. The aux input is high impedance and very sensitive so what you're hearing are voltage spikes coming from where is hard to tell. A filter would be hard to design considering 8 ohms on one side and a good 10K or more on the other so I really wouldn't bother. CB being "lo-fi" to begin with I see no advantage in pumping it through the stereo, if the internal CB speaker doesn't cut the muster an extension speaker will.

Problems? I don't see any problems but you making mountains out of mole hills. (;->)
Reply With Quote
  #3 (permalink)  
Old 11-19-2012, 5:37 PM
mmckenna's Avatar
Member
   
Join Date: Jul 2005
Location: SNCZCA01
Posts: 2,883
Default

A voltage spike would be highly unlikely in a vehicle, more unlikely that it would only affect your CB radio.

Have you tried putting a meter on the power lead to see what is going on? I'd suspect it's either a problem with your CB, or you have a loose connection somewhere in your circuit.

I agree with Warren, you really need to fuse your positive lead as close to the battery as you can. You've got the makings for a bad situation there.
Reply With Quote
  #4 (permalink)  
Old 11-19-2012, 5:44 PM
topgun1986's Avatar
Member
  Premium Subscriber
Premium Subscriber
Amateur Radio Operator
Amateur Radio
 
Join Date: Sep 2012
Location: Southeastern Missouri
Posts: 127
Default

I completely overlooked the placement of the fuse. Thanks for the info.

As far as the "sporadic surges" through the cb, I did have a Cobra 19 DX IV installed in my jeep (prior to the Cobra 25 GTL WX) and never had any problems with this "sporadic surge."

Perhaps there could be something in the newer Cobra 19 that blocks out this surge/spike. Or vice versa, maybe something in the older Cobra 25 is causing the surge.

As far as the audio, I have connected the Jeep factory speakers up to my hand held Radio Shack Pro-82 scanner (via the AUX jack on Jeep and earphone jack on scanner) with great results. Just assumed I would get the same result with the EXT SPKR jack on the cb radio and not have to install an actual external CB speaker for better/louder audio output. Jeeps have a tendency of being noisy in the cab as it is. Already having factory speakers on the jeep roll bar, I thought I would give it a shot. Live and learn.
__________________
2011 Silverado - Icom IC2410A, Radio Shack Pro 106 scanner,
Shack- Icom IC2400A, Radio Shack Pro 197, Pro 163, Pro 2067, Cobra 29 LX
Reply With Quote
  #5 (permalink)  
Old 11-19-2012, 8:24 PM
Member
   
Join Date: Feb 2012
Location: Reading, PA
Posts: 87
Default

First, there is something wrong with the radio...if the truck isn't running, there is no reason for the electrical/charging system to be causing voltage spikes (unless the battery is in a critical fail). It sounds like a cold solder problem on the radio's board.

Secondly, you are getting a ground loop when hooking up the auxiliary input to your stereo...and that is causing feedback.
Reply With Quote
Sponsored links
  #6 (permalink)  
Old 11-19-2012, 8:25 PM
mmckenna's Avatar
Member
   
Join Date: Jul 2005
Location: SNCZCA01
Posts: 2,883
Default

I'm thinking you really need to check your connections. There shouldn't be any surges on your electrical system. Any surge you might see would come from the alternator, and would affect the entire vehicle, not just the CB. CB's don't have any surge suppression on the DC inputs as far as I know. Arcing can cause momentary voltage changes (up and down) on the circuit, I'd be concerned about that. Also, make sure you wiring isn't rubbing anywhere on a sharp edge.

As for the External Speaker, likely the speaker output on your CB is a higher level than your scanner. I'd second the external speaker set up. I have a very quiet 2011 F150 with two CDM1550 (VHF and UHF) and I installed two external speakers. The internal speakers, while they worked well, were quite small and had a tinny sound (more treble). The external speakers are larger and have much better sound. If you put in a good quality speaker, like one of the Motorola external speakers, you'd likely be quite pleased with the improved audio quality.
Reply With Quote
  #7 (permalink)  
Old 11-19-2012, 9:50 PM
kb2vxa's Avatar
Completely Banned for the Greater Good
  Amateur Radio Operator
Amateur Radio
 
Join Date: Mar 2005
Location: Point Pleasant Beach, N.J.
Posts: 6,127
Default

It just hit me, I had an in line fuse holder melt due to high contact resistance or what may be considered a loose connection. The increase in lamp brightness could be from normal voltage, the rest of the time somewhat low for the same reason the holder melted. Check your connections and solder them for good electrical continuity. Today the automotive industry uses blade fuses such as these, having a large contact area and pressure offering low resistance I recommend them.

The reason your hand held didn't make all that static is because it was grounded at only one point, the aux input to the stereo. The CB being grounded to the battery and possibly the vehicle frame as well formed a ground loop when you connected it to the stereo. Grounded or not you made a loop antenna. Now that you gave that additional information we have a comparison and a really big clue.

Last edited by kb2vxa; 01-02-2013 at 6:51 PM..
Reply With Quote
  #8 (permalink)  
Old 11-20-2012, 2:24 AM
KK6BDZ's Avatar
Member
  Audio Feed Provider
Audio Feed Provider
Amateur Radio Operator
Amateur Radio
 
Join Date: Nov 2007
Location: Gridley, CA - Butte County
Posts: 219
Default

For the cb to stereo, did you use a stereo to mono adapter, the static could be the stereo tip not matching the mono socket on the cb.
__________________
http://buttewxspotter.com/
G.R.E. PSR-600/500
Cobra 29 LTD NW WX
Kenwood TM-281

Last edited by rubicon05; 11-20-2012 at 2:27 AM..
Reply With Quote
  #9 (permalink)  
Old 11-20-2012, 8:34 AM
Member
  Amateur Radio Operator
Amateur Radio
 
Join Date: Dec 2011
Location: Shawnee Kansas (Kansas City)
Posts: 681
Default

I agree with everyone else that a voltage surge is somewhat unlikely. All of us know that a voltage surge would be a momentary increase in the normal voltage. Perhaps that is not what is happening. Could you describe your "voltage surge" to us and how you determined it is a voltage surge?

BB
Reply With Quote
Sponsored links
        
  #10 (permalink)  
Old 11-20-2012, 9:37 AM
topgun1986's Avatar
Member
  Premium Subscriber
Premium Subscriber
Amateur Radio Operator
Amateur Radio
 
Join Date: Sep 2012
Location: Southeastern Missouri
Posts: 127
Default

Rubicon05...
No adapter was used. With the ground loop that I have created from cb ext speaker, could this mono adapter make a big improvement?

Sdeeter19555...
Pardon my ignorance, but what would a cold solder problem on the radio's board look like? Being an older, used radio, it could surely be something loose internally. What's confusing is the radio was getting these surges even when parked in my garage with the ignition off, until I eventually unplugged radio until I could investigate further on this week.

I will go back through the connections/fuses this evening making sure they are all tight and firm. Sounds like I will also try finding a good mounting spot for an external CB speaker. I will look into the Motorola type. Thanks for the tip.

BTW, how do I include comments from previous posts into my message, like I have seen done by others? Sure makes it easier to understand when I am replying to a specific post/comment. I've tried copy and paste technique but I don't believe thats right.
__________________
2011 Silverado - Icom IC2410A, Radio Shack Pro 106 scanner,
Shack- Icom IC2400A, Radio Shack Pro 197, Pro 163, Pro 2067, Cobra 29 LX
Reply With Quote
  #11 (permalink)  
Old 11-20-2012, 9:49 AM
Member
   
Join Date: Dec 2006
Location: Oklahoma
Posts: 2,145
Default

Just something else to consider.
Almost all newer computer equipped vehicles are never turned completely 'off', there's a draw by the computer system when it checks things. That draw shouldn't be much at all, but it's there.
- 'Doc
Reply With Quote
  #12 (permalink)  
Old 11-20-2012, 10:20 AM
proudpoppy's Avatar
Member
   
Join Date: Mar 2004
Location: Greer
Posts: 24
Default

BTW, how do I include comments from previous posts into my message, like I have seen done by others? Sure makes it easier to understand when I am replying to a specific post/comment. I've tried copy and paste technique but I don't believe that's right.

There is a quote button in the lower right hand corner of the message press it and see what happens !!
Reply With Quote
  #13 (permalink)  
Old 11-20-2012, 12:37 PM
KK6BDZ's Avatar
Member
  Audio Feed Provider
Audio Feed Provider
Amateur Radio Operator
Amateur Radio
 
Join Date: Nov 2007
Location: Gridley, CA - Butte County
Posts: 219
Default

im not if it is the cause of the ground loop, but if you look at the difference between the stereo and mono plugs, you could be putting ground to one side of the stereo inputs, you can get one @ radio shack for like $3, if you listen to your setup now, is there only audio on one side, use the balance on the stereo to see if your only hearing it on the left or right side. I had this issue using my psr-500 with the same setup, pluging it into the stereo in the mobile.
__________________
http://buttewxspotter.com/
G.R.E. PSR-600/500
Cobra 29 LTD NW WX
Kenwood TM-281
Reply With Quote
  #14 (permalink)  
Old 11-20-2012, 2:17 PM
mmckenna's Avatar
Member
   
Join Date: Jul 2005
Location: SNCZCA01
Posts: 2,883
Default

That would make sense. The stereo plugs use the same tip size as the mono plugs. The stereo plugs "rob" some of the sleeve that is often the ground or shield. This would connect one of the channels on the input to the Jeep stereo to ground.
Reply With Quote
  #15 (permalink)  
Old 11-20-2012, 5:25 PM
Member
  Premium Subscriber
Premium Subscriber
 
Join Date: Jun 2006
Posts: 3,697
Default

I think sdeeter is right, when the vehicle is turned off there is nothing to cause a voltage spike and there may be a problem in the radio.

The noise while using the stereo aux input is usually alternator whine entering the wires from a ground loop or difference in potential between the radio stereo ground and CB ground where current is flowing on the braid of the aux input cables and any alternator noise gets induced into the aux input.

In this case a transformer between the CB speaker out and stereo aux in or cut the braid of the aux in cable and bridge with maybe 100uf of capacitance which will block DC current.
prcguy



Quote:
Originally Posted by sdeeter19555 View Post
First, there is something wrong with the radio...if the truck isn't running, there is no reason for the electrical/charging system to be causing voltage spikes (unless the battery is in a critical fail). It sounds like a cold solder problem on the radio's board.

Secondly, you are getting a ground loop when hooking up the auxiliary input to your stereo...and that is causing feedback.
Reply With Quote
Sponsored links
  #16 (permalink)  
Old 11-20-2012, 8:02 PM
topgun1986's Avatar
Member
  Premium Subscriber
Premium Subscriber
Amateur Radio Operator
Amateur Radio
 
Join Date: Sep 2012
Location: Southeastern Missouri
Posts: 127
Default

After some more digging, it is for sure the CB, as plenty of you pointed out earlier. I took it down to my workbench and hooked up to a 12VDC power supply and it is still doing the whole "burping" thing. Here is a short video of exactly what it is doing.

IMG 3566 - YouTube

And I was mistaken on the model number. It is a Cobra LTD, not GTL.
I just installed my spare Cobra GTL into the jeep when I pulled this one out, and so far, that CB radio is working fine, with no burping.
__________________
2011 Silverado - Icom IC2410A, Radio Shack Pro 106 scanner,
Shack- Icom IC2400A, Radio Shack Pro 197, Pro 163, Pro 2067, Cobra 29 LX

Last edited by topgun1986; 11-20-2012 at 8:06 PM.. Reason: more information
Reply With Quote
  #17 (permalink)  
Old 11-21-2012, 1:51 PM
kb2vxa's Avatar
Completely Banned for the Greater Good
  Amateur Radio Operator
Amateur Radio
 
Join Date: Mar 2005
Location: Point Pleasant Beach, N.J.
Posts: 6,127
Default

EEK! That thing is turning itself on at random intervals! If it were burping I'd suggest Pepto Bismol but this thing needs Ghost Busters or at the very least an exorcist.

Seriously, I have never seen anything like this before but obviously something is wrong with the radio, not the installation. This is a problem that can never be diagnosed by remote control so your best bet is a competent technician armed with a schematic, proper diagnostic instruments (not CB crap) and just in case... bell, book and candle.
Reply With Quote
  #18 (permalink)  
Old 11-21-2012, 2:22 PM
Member
   
Join Date: Feb 2012
Location: Reading, PA
Posts: 87
Default

Quote:
Originally Posted by topgun1986 View Post

Sdeeter19555...
Pardon my ignorance, but what would a cold solder problem on the radio's board look like? Being an older, used radio, it could surely be something loose internally.

A cold solder joint is basically a solder joint where both halves weren't hot enough for the solder to bond correctly, and typically leads to intermittent electrical contact; very similar to what you have here...they are not easy to spot.

It could also be a loose grounding screw inside the radio, or a broken power wire/connection inside radio...it won't hurt anything to open the case and see if there is anything that jumps out as "hey, that's probably not good". Don't go adjusting anything, but there's nothing wrong with checking for broken wires and/or loose grounds. If nothing jumps out, then its off to the technician...of which there aren't many good ones...
Reply With Quote
  #19 (permalink)  
Old 11-21-2012, 11:08 PM
topgun1986's Avatar
Member
  Premium Subscriber
Premium Subscriber
Amateur Radio Operator
Amateur Radio
 
Join Date: Sep 2012
Location: Southeastern Missouri
Posts: 127
Default

Ok...

I took the outer, metal shells off the CB radio, gave the circuit board a good glance over to make sure nothing was obviously wrong. No burn marks, no loose wires sticking up, nothing out of the ordinary.
So I put both the black, metal outer shells/covers back on the radio and it hasn't "burped" yet. Obviously, something very miniscule was loose and has hopefully corrected itself (fingers crossed).

BUT...
now the audio from the CB radio is half-strength, at best. Turn volume knob all the way up and you can barely hear static coming out of speaker. I turn the SQUELCH down to try and get noise out of the speaker and I can barely even hear it then.

Anyone else have this many odd problems when getting into the hobby? :-)
__________________
2011 Silverado - Icom IC2410A, Radio Shack Pro 106 scanner,
Shack- Icom IC2400A, Radio Shack Pro 197, Pro 163, Pro 2067, Cobra 29 LX
Reply With Quote
  #20 (permalink)  
Old 11-22-2012, 12:14 AM
k3cfc's Avatar
Member
  Amateur Radio Operator
Amateur Radio
 
Join Date: Feb 2011
Location: Beavertown Pa.
Posts: 705
Default

Quote:
Originally Posted by topgun1986 View Post
Ok...

I took the outer, metal shells off the CB radio, gave the circuit board a good glance over to make sure nothing was obviously wrong. No burn marks, no loose wires sticking up, nothing out of the ordinary.
So I put both the black, metal outer shells/covers back on the radio and it hasn't "burped" yet. Obviously, something very miniscule was loose and has hopefully corrected itself (fingers crossed).

BUT...
now the audio from the CB radio is half-strength, at best. Turn volume knob all the way up and you can barely hear static coming out of speaker. I turn the SQUELCH down to try and get noise out of the speaker and I can barely even hear it then.

Anyone else have this many odd problems when getting into the hobby? :-)
Yea i have had problems like this...usually repaired them my self.
Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

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



All times are GMT -5. The time now is 6:32 PM.


Powered by vBulletin® Version 3.8.2
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
All information here is Copyright 2012 by RadioReference.com LLC and Lindsay C. Blanton III.Ad Management by RedTyger
Copyright 2011 by RadioReference.com LLC Privacy Policy  |  Terms and Conditions