Question about Radio Communications

1 Answer

Cobra 29 ltd classic will not key up

Swr meter swings backward

Posted by Anonymous on

Ad

1 Answer

  • Level 3:

    An expert who has achieved level 3 by getting 1000 points

    All-Star:

    An expert that got 10 achievements.

    MVP:

    An expert that got 5 achievements.

    Genius:

    An expert who has answered 1,000 questions.

  • Radio Commun... Master
  • 1,795 Answers

Sounds like a keydown diode and resistor to me

Posted on Oct 04, 2014

Ad

6 Suggested Answers

6ya6ya
  • 2 Answers

SOURCE: I have freestanding Series 8 dishwasher. Lately during the filling cycle water hammer is occurring. How can this be resolved

Hi,
a 6ya expert can help you resolve that issue over the phone in a minute or two.
best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.
the service is completely free and covers almost anything you can think of (from cars to computers, handyman, and even drones).
click here to download the app (for users in the US for now) and get all the help you need.
goodluck!

Posted on Jan 02, 2017

Ad
  • 773 Answers

SOURCE: cobra 29 ltd classic cb not transmitting

Check the ground. Make sure its grounded well on bare metal. To see if the ground is bad, or not making good connection, disconnect the antenna and turn it on. if it does not power up, that means your ground is bad, and it was grounding only through the antenna.

Make sure not to key up with out the antenna connected.

Posted on Feb 08, 2009

audio20
  • 22 Answers

SOURCE: swr meter not moving.

If the radio is working don't worry about the meter unless you absolutely want it. These little meters are not very accurate or reliable. Get an external SWR meter to check the antenna.

Posted on Apr 23, 2009

  • 773 Answers

SOURCE: cobra 29 ltd classic antenna calibration ??

Wow. That's not at all a solution to what this guy is asking. And why all the caps??

The one point jm77437 has that is correct is that you do not set the radio, you set the antenna. The rest is blah blah.

Here is how you tune your antenna for you radio. First off it depends on what kind of antenna you have. most fiberglass antennas have a tunable tip to adjust the height of the antenna. Metal whips either have a collar at the base that the whip will either slide up or down in to adjust the height. The other type of metal whip's you have to physically clip to shorten the antenna, you must be careful with this type because once its clipped, that's it. You cannot add what you cut off.

I am going to give this example using a metal whip with an adjustable collar.

First after your radio is hooked up in the vehicle, drive to an open lot. Buildings and other structures can cause extra reflection. turn to channel 1. Flip the meter to CAL. Key the mic without talking. Now turn the CAL knob up until the needle reaches the little upside down triangle all the way to the right marked CAL. Now you have just celebrated your radio for your setup to measure you SWR. Now while still holding the key, flip the meter switch to SWR. The needle will move, and where it stops is your SWR reading. The lower the better. Anything under 1.5 is considered really good. But still, the lower the better.

Make note of what your SWR was on ch 1.

Now flip to channel 40. Repeat the SWR process. You must recalabrate each time you take a reading.

Now like jm77437 said. If your SWR reading is higher on 40 then 1, then your antenna is too long, and you must make it shorter. Loosen the collar and lower the antenna in the collar 1/4 inch at a time. check the swr each time you adjust the antenna.

If your SWR reading is higher on channel 1, then your antenna is too short. You must make your antenna longer. Do this by loossening the collar and pulling the antenna upward in the collar 1/4 inch at a time, again checking the swr each time you adjust the antenna.

What you want to achieve is having the same SWR reading on channel 1 and 40. then you have the best match you are going to get with that antenna.

If your swr is under 1.5 on all channels, you don't need to fuss unless you are a perfectionist. then by all means go ahead.

If your reading is higher then 3, or your ant light comes on, something is really wrong. Make sure your antenna is connected all the way, and the coax is not damaged.

Its important to have an appropriate SWR because if you do not, you are reflecting too much signal back into the radio, and eventually you will burn out your final transistor, and your radio will be toast.

Some tips: make sure you check the swr with the doors and windows shut. Make sure you are in an open lot. Remember to calabrate ecah time you take a reading. If you have had your radio peaked by a radio shop, and they have lowered your dead key, or have done a swing modification, then the meter in your radio will not work when taking an SWR reading and you will have to use an external meter.

Posted on Apr 24, 2009

  • 773 Answers

SOURCE: cobra 29 ltd classic antenna calibration ??

You should not calibrate the antenna before you install it on the car!! the antenna needs to be calibrated on the vehicle that it is going to be on. Type of vehicle, different mounts, and many other variables can change the amount of reflection you will get.

j0hn9999 did a much better job but left some info out.

Take your SWR readings on channel 1, then on channel 40.... NOW, if your SWR is higher on ch 40 then ch 1, then your antenna is too long and it needs to be shortened. Refer to the antenna instructions on how to shorten the antenna.

If your SWR is higher on ch 1 then on ch 40 then your antenna is too short. You must lengthen the antenna. Again refer to your antenna instructions on how to lengthen your antenna.

You must calibrate each time you take a reading.

Make sure your doors and windows are shut when taking a reading

Make sure you are in an open lot when taking a reading as buildings, trees and other structures can cause reflection and give you an inaccurate reading.

If you adjust the length of your antenna on another vehicle and then put it on yours, the SWR will be off. It will need to be tuned again.

An external meter is better then the one in the radio, but will need to be hooked up in the vehicle you have the antenna on.

If you are not running any kind of power, or do not have a swing kit installed, and the radio is stock, the meter in the radio is more then enough to get a correct SWR reading.

Posted on Apr 24, 2009

  • 773 Answers

SOURCE: cobra 29 ltd classic ant light

Your SWR is probably NOT fine. You need to use an external meter if you have had work done to the radio. Especially if you have had a swing mod done to the radio. When you do this, the dead key of the radio is lower then the calibration knob on the radio can adjust for. It will always come up lower then it actually is.

Your radio might have been fine before the work was done on it because it was putting out very little power. Now you are most likely putting out 50 watts or more. Big jump from 4 watts.

When your raise the power in a radio, you will notice more when the antenna is not properly tuned.

In most cases with a stock CB, even when the antenna is not even near tuned, you will get a reading less then 1.5 anyway.

the more power you put out, the more important it is to have a good match.

But an external SWR meter, and check it. be careful if the ANT light is on.

You might also want to check your coax, connections to it, and your antenna for anything wrong.

Posted on Apr 24, 2009

Add Your Answer

Uploading: 0%

my-video-file.mp4

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

×

Loading...
Loading...

Related Questions:

2 Answers

Got a cobra 29 ltd classic dead keys 10 watts and swings back to 6 watts on an external meter any answers


Hi you have to make sure your antenna has 1:1 SWR reading improper use of antennas deplete the Effective radiating Power of Transmitting equipment such as the CB radio.

Mar 15, 2016 | Cobra Radio Communications

2 Answers

Cobra 29 now Ltd classic Cobra 29 nw.ltd classic receives not well but does not transmit don't even move the swr./power meter any ideas


High SWR on antenna system.. may have mess up your RF final transistors. if you were talking on it for a long time. have someone check the SWR on the antenna system... should be a FREE service.

Jul 13, 2014 | Radio Communications

1 Answer

How do you set the SWR on a cobra 29 LTD classic radio


the same way you set it on any other radio.Look at the face of the set,you will see a switch that says S/RF,CAL , SWR. Now look at your meter and you will see a triangle that shows cal.Put your set on ch 1 with the switch in the cal position and bring the needle to that calibrate line on the meter by keying the mic. now release the key and set switch to SWR and key the mic again.Now write this reading down.Repeat for channels 40 and 19. If the reading is higher on 40 than on 1 you need to shorten the ANTENNA.If its higher on 1 than 40 you need to make your ANTENNA longer Always check 19 to make sure you have an average SWR. Any reading under 1.9:1 is good

Jun 15, 2014 | Cobra 29 LTD CB Radio

2 Answers

How to match a antenna to a cobra 29 LTD Classic


You are actually tuning the antenna to the vehicle it is mounted on here are some very good resources. http://www.rightchannelradios.com/pages/cb-antenna-tuning-guide-pv-c0-61.htmlhttp://www.wilsonantenna.com/swr.php

Be aware that if your radio has been modified it may produce a dirt signal that an swr meter may read as reflected power. In this case it may be more accurate set with a unmodified radio also if your radio is setup for a linear it may have a deadkey to low for the swr meter to calibrate correctly.
Hope this was of help.

Nov 26, 2011 | Cobra 29 LTD CB Radio

1 Answer

I have a Cobra CB Radio and was wondering if I have it on SRF or SWR or CAL


S/RF/SWR/CAL SWITCH. When in the S/RF position, the meter swings
proportionally to the strength of the received signal. When transmitting,
the meter indicates relative RF output power.
When in the "CAL" position, the SWR meter can be calibrated by adjust-
ing the "SWR CAL" control to the "CAL" mark on the meter face.
When in the "SWR" position, the standing wave ratio is measured.

You will want to operate on S/RF position.

Jul 14, 2011 | Cobra 29 LTD CB Radio

1 Answer

I want to calibrate my cobra 29 NW Ltd. Classic


Calibrate For SWR (Standing Wave Ratio) http://www.cbtricks.com/radios/cobra/29ltd_bt/graphics/cobra_29ltd_bt_om.pdf
The CAL is only to calibrate meter for a swr check of you antenna system it does not calibrate radio.

Jan 11, 2011 | Cobra 29 LTD CB Radio

2 Answers

Cobra 29 ltd classic ant light


Your SWR is probably NOT fine. You need to use an external meter if you have had work done to the radio. Especially if you have had a swing mod done to the radio. When you do this, the dead key of the radio is lower then the calibration knob on the radio can adjust for. It will always come up lower then it actually is.

Your radio might have been fine before the work was done on it because it was putting out very little power. Now you are most likely putting out 50 watts or more. Big jump from 4 watts.

When your raise the power in a radio, you will notice more when the antenna is not properly tuned.

In most cases with a stock CB, even when the antenna is not even near tuned, you will get a reading less then 1.5 anyway.

the more power you put out, the more important it is to have a good match.

But an external SWR meter, and check it. be careful if the ANT light is on.

You might also want to check your coax, connections to it, and your antenna for anything wrong.

Apr 22, 2009 | Cobra 29 LTD CB Radio

3 Answers

Cobra 29 ltd classic antenna calibration ??


You should not calibrate the antenna before you install it on the car!! the antenna needs to be calibrated on the vehicle that it is going to be on. Type of vehicle, different mounts, and many other variables can change the amount of reflection you will get.

j0hn9999 did a much better job but left some info out.

Take your SWR readings on channel 1, then on channel 40.... NOW, if your SWR is higher on ch 40 then ch 1, then your antenna is too long and it needs to be shortened. Refer to the antenna instructions on how to shorten the antenna.

If your SWR is higher on ch 1 then on ch 40 then your antenna is too short. You must lengthen the antenna. Again refer to your antenna instructions on how to lengthen your antenna.

You must calibrate each time you take a reading.

Make sure your doors and windows are shut when taking a reading

Make sure you are in an open lot when taking a reading as buildings, trees and other structures can cause reflection and give you an inaccurate reading.

If you adjust the length of your antenna on another vehicle and then put it on yours, the SWR will be off. It will need to be tuned again.

An external meter is better then the one in the radio, but will need to be hooked up in the vehicle you have the antenna on.

If you are not running any kind of power, or do not have a swing kit installed, and the radio is stock, the meter in the radio is more then enough to get a correct SWR reading.

Sep 27, 2008 | Cobra 29 LTD CB Radio

Not finding what you are looking for?
Radio Communications Logo

Related Topics:

58 people viewed this question

Ask a Question

Usually answered in minutes!

Top Radio Communications Experts

eradiostore
eradiostore

Level 3 Expert

1654 Answers

Brad Brown

Level 3 Expert

15639 Answers

Mike Charette

Level 3 Expert

1795 Answers

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

Answer questions

Manuals & User Guides

Loading...