Stephens2r

Hey Guys,

I'm not the most knowledgable when it comes to CBs, but I have tried to troubleshoot my problems using existing forum threads without any luck.

I have the Uniden 510 kit from right channel radios with the Teraflex mount. I removed some of the material on the mount and grounded it to my frame. I have checked continuity to ensure that it is in fact grounded. I also made sure that the COAX was routed without any kinks, pinches, or loops in the cable. I routed it along the passenger side underneath the carpet and then under the front passenger seat.

When testing the SWR, I follow the directions included, and when I switch the meter to "REF", the meter pings all the way to the right. I have no idea what could be causing this. Any advice on how to fix this would be greatly appreciated.

TURTLECON

Are you using an external SWR meter? Does your antenna have a tunable tip?

Stephens2r

Yes, I am using an external meter. It is the one that came with the kit, not sure of the brand. The antenna is a 3' Firestik adjustable.

OH9JK

Do you own a multimeter?

If so, I would check to make sure your coax or antenna does not have a short in it.

Typically SWR is high with that mount but not pegging the meter.

Stephens2r

I am pretty bad with electronics, can you please explain to how to check if there is a short in the COAX.

groovebus

Checking coax with a multi meter:

1. Set the multimeter to either the resistance check (ohms) or diode tester (beeps when shorted).
2. Check between center pins to make sure there is no resistence.
3. Then test between the center pin and the out side metal part that screws on to the antenna. If it is good there should be no connection and infinite resistance.

hypeiv

Make sure the top of the antenna stud is isolated from the ground. You might have a short in your antenna. Also make sure you are testing the swr in an open area.

Gjeffers

[QUOTE="Stephens2r;3826487"]Hey Guys, I'm not the most knowledgable when it comes to CBs, but I have tried to troubleshoot my problems using existing forum threads without any luck. I have the Uniden 510 kit from right channel radios with the Teraflex mount. I removed some of the material on the mount and grounded it to my frame. I have checked continuity to ensure that it is in fact grounded. I also made sure that the COAX was routed without any kinks, pinches, or loops in the cable. I routed it along the passenger side underneath the carpet and then under the front passenger seat. When testing the SWR, I follow the directions included, and when I switch the meter to "REF", the meter pings all the way to the right. I have no idea what could be causing this. Any advice on how to fix this would be greatly appreciated.[/QUOTE Make sure your coax is cut in a 3ft interval. Example is a 18 ft coax is a great length, a 16 ft cable will not have good swr's no matter how much you adjust!

OH9JK

That is a myth....use whatever length coax gets you from the radio to the antenna.

psouza

This is %100 true, but.....there is a physical property of transmission lines that causes this myth to reappear time and again. The VSWR measurement is a voltage ratio and the voltage varies along the length of the coax if the ratio is not 1:1. The ratio can ALWAYS be accurately measured at the base of the antenna and the readings can be different at the back of the radio if the VSWR is more than 1:1. If the length of the coax is such that the voltage at the measure position is zero then the reading will appear as 1:1 even if the VSWR at the antenna is reading 9.5:1 or worse. When measuring VSWR at the back of the radio, trimming or lengthening the coax may appear to reduce (or increase) the VSWR, but it does not change the system VSWR at all! The return power remains the same as does the loss caused by the reflections.

There is a portion of this link from the ARRL that explains is quite well. I have posted this in another thread on this forum, for a different reason so I may appear to be a "One Trick Pony". For tonight perhaps.

There is a section in the article that depicts the relationship of measured VSWR to actual power lost. Should give perspective to the worriers who obsess over the ratio numbers. Kind of a mental health aid.

http://www.arrl.org/files/file/Techn...f/q1106037.pdf

Phil