Question about CB Radios

1 Answer

Modulation radio seems to have very small amount of forward swing when speak into the mike . i have hade radio tuned and tried 3 or 4 mikes. set at 5 watts and maybe swing to 6 or 7 watts on radios meter and a good external meter. radio is 1 year old . finals are ok also. swr good. ant 2 k40 5k

Posted by on

1 Answer

  • Level 1:

    An expert who has achieved level 1.

    Problem Solver:

    An expert who has answered 5 questions.

  • Contributor
  • 2 Answers

Have you happened to check the cable to your antennas? maybe you got a cut in the insulation. thats the only idea i can come up with being that you have had all the work done to it and still havin problems.

Posted on Oct 21, 2008

Add Your Answer

Uploading: 0%

my-video-file.mp4

Complete. Click "Add" to insert your video. Add

×

Loading...
Loading...

Related Questions:

1 Answer

Have a sequel when keyed up


If this is a powered mike the modulation is set to high. If you have a standard mike check your settings on the radio, if that does not help sub another mike.

Apr 03, 2012 | Cobra 29 LTD CB Radio

1 Answer

How do i find and turn up modulation


If your asking for an internal adjustment,you need to be a qualified technician to do this and the radio's schematics..which I don't know either answer to,so external adjustments would be mic gain knob,you can also gain modulation by lowering the output power knob,both can be adjusted to get the most forward swing by watching your meter swing when am or sideband transmitting.If you are using the stock mike,you could also upgrade to power mic properly wired for your radio.If you are a qualified to do so,there are online sites that have info on upgrading the modulation to this 10 meter radio by adjustments,modifications and add on parts,which does require an amateur license to operate unless modified for cb bands and only transmits on these bands..according to fcc rules.

Aug 14, 2011 | Magnum DeltaForce CB Radio

1 Answer

Reception is fine, cannot transmit. checked swr's and all below 2. how to check out transmission modulation?


To see if your radio is "modulating" you need to do one, or both of these things. The first and easiest is to look at the RF/Signal meter in your radio. If you see forward movement of the needle then you know the radio is modulating the carrier. NOW, the second and best way to see if the radio is modulating is to go out to your local Truck Stop and purcase a Power/SWR meter. They generally run about $30 bucks. You will also need a short coax jumper (at least 3 feet, no more than 6 feet) to link the radio/meter/antenna. By the way, they should go in that order. The meter will be clearly marked as to how to hook it up and it will come with instructions.
To check forward modulation, the meter should be in Power mode (not SWR mode) with the power scale switch set to 10 watts. You then key the microphone. You should see a carrier (dead key) of about 4 watts. To check for proper modulation, you should then speak into the mic at a normal level. You might try saying AAAAUUUDDDIIIOOO (audio). If the radio is working properly the needle should rise off of 4 watts and swing forward to around 8-10 watts....give or take a few, depending on weather or not the radio has been modified (peaked and tuned). If you see forward movement on the meter, you know it is working properly.
If you do see that the radio is modulating properly but you cant seem to contact anyone on the air waves, then you need to start looking at your antenna setup. I will not go to deep into this subject because it is so extensive. The antenna system is VERY important. you said you checked SWR and it is below 2. This is a little high...but acceptable. You should really try to get your SWR as close to 1.0 : 1 as you possibly can. Hope this helped. Lost Jeep, Athens GA, 10-7 !!!

Feb 18, 2011 | Cobra 29 NW CB Radio

1 Answer

Will not get good recepiton.


Hi stormnorm157,

Much of the time this is caused by problems in the antenna system. Make sure there are no shorted or open connections in the coax or PL-259 connectors. Use your radio's meter or better still, a Power/SWR meter to check the SWR of the antenna. Try to get that as close as possible to a 1:1 ratio on the meter. A shorted or open antenna can keep the audio receive on your radio at very low levels. Plus, this will harm your transmitter if you continue keying the mike.

Another problem can be in the radio itself. This will be noticed if you can transmit, but have no "Modulation". Modulation can be described as the voice heard above the "Carrier" (your transmitted signal). Every CBer knows about the term, Modulation. The Truckers will definitely inform you about your modulation quality...lol. This problem can be due to a defective AMC (Automatic Modulation Control) stage in the receiver circuit. And, there will be no modulation upon transmit.

One other thing could be causing this lack of receive. Defective wiring or switching in the microphone can result in no audio. Or, in many radios, a missing mike will not allow receive, because the mike connection completes the RX (Receive) circuit.

Solutions:
1. Check the antenna system, and rule that out or fix.
2. Check mike, or substitute another one.
3. Using meter, and or another radio for listening on same channel, check power and receive.
4. You can probably fix 1 and 2 yourself, or with a friend.
5. AMC problem in radio (as described above) will require professional service.

Let me know how this turns out, and inform me if I can offer any more help. Thanks.

Regards, Bill

Sep 18, 2010 | Midland 1001Z 40-Channels Base CB Radio

2 Answers

I have a general lee and I am running a 2 by 8 box. What should I turn my radio down too to run this box I was told 3 watts wgat do I turn to accomplish this I doesn't seem to have much modulation either


The radio needs to be tuned for the box. 3 watts sounds too high for a 2x8.

I would say it would be more like 1-1/5 to 2 watts. That may be why your not getting that much swing.

You should set the radio so the box dead keys around 300 to 400 watts.

Aug 24, 2010 | Cobra 148 GTL 120-Channels Base CB Radio

1 Answer

COBRA 21 GTL NO MODULATION NO RX. BUT IT WILL TX AT 3 WHATTS.I HAVE TRIED 3 DIFFERENT.MIC ON THIS RADIO CAN YOU HELP ME


That's usually a defective amc stage that produces RX audio and TX modulation. It's an integrated circuit that will require a tech fixing it. You will have a transmitted carrier with no modulation, and no sound in your speaker. However, make sure you have a good mike plugged in first, and substitute a known good mike to verify it's not the mike.

Jul 30, 2010 | CB Radios

1 Answer

Key mike no hears me but shows meter


You didn't mention if you hear the other radio. If not, here's a common problem and solution.
That's usually a defective amc stage that produces RX audio and TX modulation. It's an integrated circuit that will require a tech fixing it. You will have a transmitted carrier with no modulation, and no sound in your speaker. However, make sure you have a good mike plugged in first, and substitute a known good mike to verify it's not the mike.
However, if you hear them, and they see your signal, but no talk (modulation), then the problem is usually your mike. Try another one in this case. Thanks, Bill

Jul 27, 2010 | Cobra 19 Ultra II CB Radio

1 Answer

Keying the mike


Hello Adam, first off, do not unhook the antenna then key the mic; you run the risk of blowing the final transistor out of the radio, then it will not TX.
The digital TX lights can be adjusted high or low by a cb tech. All they are is a general reference as to how much power is being dead keyed; usually around 4 watts.
For the best performance, the antenna needs to have the SWR set with a meter so all your signals are getting in and out. A mismatched antenna system can lose you about half of your power and range; and that's hard on the radio also.
If your radio was tuned up by a shop tech, you would see the digital go part way up, but when you talked into the mic, the digital would go almost all the way up. I hope this clarified the situation for you,,, Let me know,,, Mechanic

Oct 28, 2008 | Radio Shack TRC-503 CB Radio

1 Answer

Cobra ltd classic no modulation


Assuming that you've tried another mike, the problem may lie in the speech amplifier circuit within the radio, something that will require someone with technical knowledge to repair.

Sep 22, 2008 | Cobra 25 LTD 40-Channels Base CB Radio

3 Answers

Mod


You never want to clip modulation limiters All youll get is a overmodulated splatterbox and it will sound like crap!! Try cbtricks.com and youll find the tuning info for that radio...Chia

Dec 24, 2007 | Cobra 150 GTL DX Base CB Radio

Not finding what you are looking for?
CB Radios Logo

Related Topics:

145 people viewed this question

Ask a Question

Usually answered in minutes!

Top CB Radios Experts

AnyMHz.com
AnyMHz.com

Level 2 Expert

489 Answers

Iron
Iron

Level 3 Expert

3018 Answers

Steve

Level 3 Expert

3287 Answers

Are you a CB Radio Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides

Loading...