View Full Version : Cobra 29 lx set up question

01-12-2016, 07:22 PM
I just installed a cobra 29 lx with a 3' firestik ii on my jeep. I am trying to set up the SWR. Followed instructions in the manual and have 1.2 SWR according to SWR meter integrated in cb (don't have a external meter to check) on all channels. My question is regardless of how I adjust the antenna tip (shorten or lengthen) it doesn't change doesn't go higher or lower. I would assume that it would change the SWR some when adjusting the antenna. Is this normal or do I potentially have a problem

01-13-2016, 06:04 AM
You truly need to get an external swr/power meter IMO to tune the antenna. Even better is an antenna analyzer at the feedpoint of the antenna. But for GP, a decent swr meter will work just fine. If you can find a radio shack near you they might have one of their meters if they still carry them or had them leftover. If not the Workman HP201 is another meter to look at as well for a starter. You will also need a coax jumper from 1-3ft long. Most use a 3ft one. Get a good one and stay away from
The radio shack coax jumpers as well!! Only purchase an swr/power meter from there!!! You can check eBay as well for the radio shack meter. It looks like the one pictured below as well as a photo of the workman meter.
Also, there may not be anything wrong with the antenna or its a DUD. Without a known good external meter though, you are taking a crap shot as to whether to trust the internal meter. And if you use the antenna and it's not right, you risk blowing your radios final. So look into getting an external swr meter at the least. Even a truck stop POS will work in a pinch!!! Hope I get it resolved. And also know that with that antenna you won't be talking or receiving very far at all. Maybe a couple miles at best!! Not much better then a handheld walkie talkie. Height is might when it comes to antenna, no matter how you slice it, the closer to 108" in total length of the antenna the better the performance will be.
All this aside. I would first like to know if you are calibrating the internal meter correctly when you are changing channels.
You should also be in an open area with no obstacles for approximately 50-100ft in all directions. Not even other vehicles or people. An open field or parking lot away from any light poles works well.
You need to start at channel 20. First set the radios mic gain all the way down.
Then set the CAL, to the correct position as noted in the owners manual.
Then set radio to SWR and take reading and note it.
Now move to channel 1 and repeat process above. Note reading. Do same for channel 40.
This should also be done with an external meter as well to verify that your internal radios meter is actually working. JMHO on the whole deal. Anyway here are the pics of the 2 meters I would look for, and also a good 3ft coax jumper. http://images.tapatalk-cdn.com/16/01/13/257410ec451f93d86c18623fbdfe7d9b.jpg
Seems as the workman HP201S is the best deal for under $40. There are better meters like a DIAWA cn101L. Personally, you don't need this much for GP and the workman meter will or should work just fine, but the Dawia meter is a better one for sure. JMHO. http://images.tapatalk-cdn.com/16/01/13/71f3061b038a239b125b1e69252b61f4.jpghttp://images.tapatalk-cdn.com/16/01/13/fbe9989239869638dd1b60e81abd31a8.jpghttp://images.tapatalk-cdn.com/16/01/13/53dda79a6284ac66ff776f1c559576fc.jpg
I posted a photo of the radio shack meter I have. They are or were $40 new when RS had them.
Again, without a proper external swr meter, I wouldn't use the radio yet. It is not worth toasting your radio!!
And also read up on antennas and how they work. The 3ft one you have is about bottom of the barrel as far as antennas go and a coat hanger will just about do the same as one. Sorry to be so harsh, but it's JMO. Again, get am external meter and coax jumper, and start over!! JMHO. Good day

09-05-2016, 03:35 AM
Hope you got everything resolved man! Having a good VSWR meter is imperative!! Again, hope all worked out for you sir. Have a good one!!