Question about CB Radios

1 Answer

Swr low on lower channels

Swr is negative on lower channels an about 2 on higher channels.i have a wilson 5000 antenna 12 heavy duty coax cable that just reaches my radio the antenna is ajusted as far as it can be

Posted by on

  • eddie41839 Jun 30, 2008

    the radio receives a nd transmits great

×

1 Answer

  • Level 1:

    An expert who has achieved level 1.

    Hot-Shot:

    An expert who has answered 20 questions.

    Corporal:

    An expert that hasĀ over 10 points.

    Mayor:

    An expert whose answer gotĀ voted for 2 times.

  • Contributor
  • 27 Answers

Connect a standard mobile antenna to the set and see if you have normal tx / tx/ audio out...if this is all aok you have a problem with the antenna / antenna equipment / installation/
GOOD LUCK

Posted on Jun 29, 2008

  • flyingfox Jun 30, 2008

    Poor earthing / ground plane is the usual problem with antennas.

    you must check that you have no "short to ground" .I assume your antenna is store bought ?The correct full wave antenna length is 11.111 meters....300,000.000 divided by a nominal

    27 meg frequency....27,000,000 = 11.11111etc

    GOOD LUCK flyingfox@people.net.au

    All emails are answered!!

×

Add Your Answer

Uploading: 0%

my-video-file.mp4

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

×

Loading...
Loading...

Related Questions:

1 Answer

Adjusted mag mount antenna w/a swr meter. When checked it w/the meter on the '06 uniden pc78 elite, ch 40 was a lot higher. Which is correct ?


The coax jumpers between the meter and the radio can change the SWR a little bit. It is very unlikely the the antenna can be that low on 1 and 40. Set it for the lowest on 20 via the radio and as long as you are under a 2 on 1 and 40 then it should be OK.

Oct 10, 2016 | Uniden CB Radios

1 Answer

Cb antenna warning


If your readings are below 0.5 with a dipole that is a excellent swr reading, most fall in the area of 2.0 or higher, you will not harm your RF output transistor, if you are getting antenna warnings see if you can recalibrate it.

May 04, 2012 | Cobra 29lx Cb Radio W/clock 29 Lx Lcd

1 Answer

-wilson antenna installation diagrams for, Wilson Trucker2000 - display pictures of exactly, how antennas appear when being attached with coax cable, using stud mount between coax & antenna mount... -...


I have a wilson 5000 mirror mount. I mount it on the drivers side mirror on the upper cross arm that goes to the mirror. It is mounted on this arm with a bracket and a so 239 connector so I can undo it if I have to ,leaving the antenna connected.I can change coax and not have to worry about undoing the antenna. Remember one thing. The antenna has to be checked for SWR.each time you move it to a different spot or to a different truck.

Oct 11, 2011 | Cobra 29 LTD CB Radio

2 Answers

I drive a Freightliner Columbia and have 2 Wilson 2000 antennas. My SWR is at a 2 and sometimes higher, while the truck is running. If the truck is off, it goes below 2. Unlatch the door, it goes lower and...


hello dcigno when you say you have two wilson 2000 antennas you mean cofaced this could be down to the lengths of coax ,are both coax lengths the same if not you would not get a perfect match also check the pl259 connectors on each antenna make sure there is no short whatsoever iff all fails just use the one antenna , and see how that works for ya ,for a more technical term the antennas should be a 1/2 wave apart taking into account the lengths of coax ,hope this helps you out above all check coax for breaks or faults goodluck

Mar 30, 2011 | Cobra 29 WX NW ST 40-Channels Base CB...

1 Answer

Having trouble setting swr .moved anttena up and down 1/4 inch at a time and there is no change


There are several things that can cause you not to be able to get an acceptable SWR.

The first is the most obvious. Poor antenna, or bad coax. Make sure your coax is good. Make sure the antenna is mounted in a good location.

Some things I have seen that cause this problem.

  • Wilson Little wil, almost impossible to get under a 1.6 SWR.
  • Fiberglass antenna's, a break in the wire near the top of the antenna. Will show the antenna as being too short, and adjusting the top will do nothing. This antenna is no good.
  • Common mode current. This is when the RF is traveling back down the outside of the coax, and or causes the coax to act like part of the antenna. SOLUTION. As close to the antenna as you can, take 6 to 8 inches of coax, and coil it into a tight coil, about the diameter of a spray paint can. In fact using a spray can to wrap the coax around works well. Use electrical tape to secure the coil so that it will stay tight and uniform. This will stop common mode.
  • missing foil/vinyl membrane on bottom of magmount antenna. This is essential for the antenna to see ground plane.
  • bad connections on coax connector.
  • Cracked isolator on stud mount.
  • incorrect procedure for taking SWR reading.
  • Poor location of antenna. E.g. antenna's load not above roof of vehicle.
  • Incorrect length whip being used.
  • corrosion of any part of the antenna system.
There are some cheap antenna's out there that you just can't get lower then say a 1.5 or worse, like the wilson little wil. Wilson makes great antenna's. The 500, 1000 and 5000, as well as their silver load antenna's are excellent. I have been able to get them all to at least a 1.1 SWR, and some like the 5000, and silver load fiberglass whip to 1.0 using an analyzer. The Little will is just a poor antenna. Anything under 2.0 SWR is okay of a barefoot radio, although I don't like going over 1.5 my self. A barefoot radio, will do a 2 swr all day. If the radio is stock, and not peaked and tuned, 2 swr is fine and won't hurt the radio.

You should always try to get the lowest SWR that you can in any case. The lower the SWR, the more RF energy is leaving the antenna. As well, receive will improve the closer you get to a perfect match. This is known as being "On Que".

Check everything I have listed that applies. And if nothing fixes it, you may want to try a different antenna. Some antenna's just don't work well on certain vehicles.

Oct 13, 2010 | Cobra 29 WX NW ST 40-Channels Base CB...

1 Answer

Cb radio


As for me ,the Wilson 1000 or Wilson 2000 are the best mobile antenna for a mobile. I have out talked a lot of base antennas with them, just put it on the top of car in the center or trunk, or middle of cab of truck, with a good SWR and you are talking and receiving. great antenna. ...hope this helps..

Jun 01, 2010 | Cobra 29 LTD CB Radio

1 Answer

Antenna light comes on when trying to transmit


Its the antenna. it is not tuned correctly for the radio. First, stop transmitting. You can burn out the final transistor. If the antenna light is coming on, that means your SWR is too high,


first. Check to make sure that the antenna coax is securely attached and fastened tightly to both the radio and antenna.

Next inspect the coax. Make sure there is no damage to it. If there is a slice in it, it is kinked really bad, that could be the problem.

Now, if the coax looks good and is connected tightly, now its on to tuning the antenna. Your antenna is either too long or too short. Antenna's usually have a way to adjust this. Most common is where a metal whip sits in a collar. You loosen the collar, and you can move the whip up and down in it. That is how you adjust the length of your antenna. Fiberglas whips usually have an adjustment at the tip that you can adjust usually by screwing it in or out.

Now here is how to check your SWR.

Make sure you are in an open area like a parking lot as structures such as buildings and trees can cause reflection and give you a false reading. Always take an SWR reading with your doors and windows shut as not doing so can also cause a false reading.

Now that you are in an open area, turn on the radio and turn to channel 20. flip the switch located all the way to the left by the signal meter to CAL. Now turn the knob all the way to the right just before the channel selector marked SWR CAL all the way down to the left before you start. Now key the mic without talking into it and turn the SWR CAL knob up until the needle on the meter is all the way to the right to the mark for CAL. its a little upside down triangle with the letters CAL next to it. You want the needle to be on that triangle. Now while still holding the key in, flip the switch all the way to the left next to the signal meter up once to SWR.

The needle should swing back giving you your SWR reading. Ideally you want this reading to be as low as possible, but 1.5 and under is acceptable. If it is higher then 3 and in the RED stop transmitting. Try to do the steps quickly so you can un key as soon as possible to avoid damage to the final resistor if the SWR is higher then 3.

If the reading is 1.5 or under and the ant light is going on, it could be something else. I will go more into this at the end.

Now we have to figure out if the antenna is too long or too short. Here is how to do this.

Turn to channel 1 and repeat the steps to take an SWR reading. Make note of the reading.

Turn to channel 40 and repeat the steps again to take an SWR reading. Not that number.

If the SWR is higher on channel 40 then channel 1, then your antenna is too long and you need to adjust your antenna so it is lower.

If the SWR is higher on channel 1 then on channel 40, then the antenna is too short, and you need to adjust the antenna higher.

If the signal is over 3 on both channels, then there is something wrong with either your coax, antenna or both, and you should replace the coax, and if its still high, the antenna.

If your antenna is too long or too short, make adjustments to correct. Raise or lower the antenna a 1/4 inch at a time. each time taking a measurement to see if it is still to long or too short. You want to try to get the SWR the same on 1 as on 40. And channel 20 will have the lowest reading.

If your SWR reads low, under 1.5, or even a 2, the light should not come on. If you have had the radio worked on at a radio shop, or purchased it from some where that modifies the radio to put out more power before they sell it, then that can cause that light to go on falsely. Purchase an external SWR meter. You can get one off ebay, or from radioshack. Check the SWR with the meter, and if the SWR is still good, then you can do 1 of the following.

1. ignore the light because it is not right.

2. go in the radio and try to adjust VR6 so that the light doesn't go on. Not recommended if you don't know what you are doing.
3. take it to a cb shop and have them adjust VR6 for you.

I would leave it alone.

Most likely your antenna is not tuned properly.

Apr 26, 2009 | Cobra 29 LTD CB Radio

2 Answers

Swr to hi and can t get it down


I hope this will help you on setting your swr put the radio on channel 1 check your swr.
now go to channel 40 check the swr. If the swr is lower on 1 than it is on 40 the antenna must be shortened buy 1/4 inch.until you reach your desired swr.if the swr is lower on 40 than it is on 1 the antenna must be lenthened by 1/4 inch until desired swr.

Mar 28, 2009 | Cobra 29 LTD CB Radio

2 Answers

Cobra 29ltd cb radio


Hi,

A couple of suggestions:
1. verify that the RF Gain is maximum clockwise;
2. verify that the ANL or noise limiter is OFF;
3. pls add a ground strap from the body of the Cobra 29LTD to the chassis/GND of the vehicle or to your house GND connection;
4. Verify that your Wilson 5000 has a sufficient ground plane such as roof or metal objects.

Hope this be of initial help/idea. Pls post back how things turned up or should you need additional information.

Good luck and kind regards.

Thank you for using FixYa.

Jun 15, 2008 | CB Radios

3 Answers

Connex 3300hp radio


Hi,

Based on your post/description:

1. how do i set the swr
Normally SWR are calibrated on your operating channel (where you usually stand-by). This is to maximize transmit power and receive sensitivity. To set SWR, switch to channel of your choice, switch SWR control to CAL, key or press PTT, while pressing PTT rotate ADJ knob until max deflection of needle on meter, release mic, switch control to SWR, key/press PTT, needle reading/deflection is SWR for that channel.

I would suspect that your SWR will vary from your current 1.4. This is because you have too big excursion of channels (240 channels).

2.reading a 1.4
This reading is good enough and should do. However as earlier stated, you seem to have 240 channels which would mean that your radio + antenna moves in a wide bandwidth and since the antenna tuning is affected by frequency, your SWR will also be affected by channel.

Best if you can further lower it down.

3. some cb cant get me
This is because the standard CB radio is only 40 channels. The next would be a 80 channel and then 120 channels.

4. is it my radio
Yes, you have a wide coverage radio almost an extended 10 meter rig.

5. do i have to set my radio on high or low to set my swr
I will assume you are referring to power output, set it to HIGH when doing SWR calibration

Hope this be of some help/idea. Pls post back how things turned up or should you need additional information.

Good luck and kind regards.

Nov 08, 2007 | Connex 3300 240-Channels Base CB Radio

Not finding what you are looking for?
CB Radios Logo

Related Topics:

127 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...