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jp4fun
11-08-2012, 08:47 PM
I drove OTR many years ago, but all I ever had to do was throw the radio in and hook everything up. The antenna,coax, and power were already there for me. I have never had to do much setup. I recently bought a Cobra 29 LTD Classic for trail rides with the Jeep club. Of course now that I have it I will be using it a little more for hobby as well. So, as you already see, I have this installed in a jeep wrangler. The antenna(3' firestick) is mounted to the spare tire carrier. Ran a ground wire from the base to the tailgate and then on to the body. At the other end I routed the hot wire directly to the battery and the negative to a ground lug beneath the dash. SWR about 1.5:1 at 1 and 40. I didn't expect any better considering the setup. However it acts like the radio is is getting insufficient power. I have lots of noise that seems to be effected by anything related to power. For instance if I flip on the turn signal the noise increases and decreases in time. So help me trouble shoot this.

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High Voltage Mobile NJ
11-08-2012, 09:11 PM
try using a longer piece of coax . that usally helps alot . at least an 18 footer. should bring ya swr down to a 1.2 or lower.

ducksoupe
11-08-2012, 09:35 PM
maybe power right from the battery ? Little work but it might get rid of interferance

High Voltage Mobile NJ
11-08-2012, 09:39 PM
maybe power right from the battery ? Little work but it might get rid of interferance


he is powered right directly to the battery.

jp4fun
11-08-2012, 09:51 PM
18 ft premade K40 coax. I don't know what type of coax it is. I assumed K40 would produce decent quality stuff. Even though its 18ft it is not coiled up anywhere do to the way it runs.

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jp4fun
11-08-2012, 09:52 PM
Would a bad ground cause this type of symptom?

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Beercanman
11-08-2012, 09:54 PM
At the other end I routed the hot wire directly to the battery and the negative to a ground lug beneath the dash. However it acts like the radio is is getting insufficient power.

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Run the ground back to the battery and double check your connections to make sure their all serviceable.

Sent from my Dave Made mobile phone.

jp4fun
11-08-2012, 10:05 PM
I'll check my connections. If that doesn't work I will run negative to battery as well. If you guys can think of anything else let me know. It will probably be this weekend before I can get back to it. Also I was considering using a relay hooked up to accessory power to interrupt my supply power in case I forget to turn the radio off. Would this cause any problems?

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ducksoupe
11-09-2012, 12:08 PM
then maybe it is the coax , i can't see a k40 in good condition causing much of a problem . make sure the battery ground is tight and no rust around it . How are the battery cables attached to the battery ? :yo:

jp4fun
11-09-2012, 02:19 PM
The coax was branded k40. Im using a firestick antenna.

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High Voltage Mobile NJ
11-09-2012, 03:14 PM
The coax was branded k40. Im using a firestick antenna.

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3 foot antenna's are harder to tune than 5 foot antenna's . just for shits and giggles if you have the extra money , try a 5 foot everhart antenna they are rated very high in wattage and get out like a bandit. or try another antenna thats a bit longer and see if your swr goes down alot . your ground should be ok. :300 (215):

ducksoupe
11-10-2012, 12:40 PM
I have used a firestick and they are good antenna's could be the coax then

BOOTY MONSTER
11-10-2012, 02:53 PM
remove the coax from the radio , DO NOT KEY MIC !!! with the radio on , if you still have the noise it's not comming from the antenna or coax but through the power lines . then you will know where you need to work on eliminating the noise at .

jp4fun
11-10-2012, 03:13 PM
remove the coax from the radio , DO NOT KEY MIC !!! with the radio on , if you still have the noise it's not comming from the antenna or coax but through the power lines . then you will know where you need to work on eliminating the noise at .

Good idea. I'll give that a try.

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Mistah Gravy
11-11-2012, 06:34 PM
you can run a noise filter inline to take some of that dirty noise out of it.it's all about your ground-which is why you're getting that noise.

like when you rev the motor,you'll get a noise.or like you said,when you turn on the blinker.....any process that is related to electrical output will cause a noise to run.get a noise filter at an auto parts store and run it inline with the power i believe(there will be instructions with the noise filter).either way good luck

jp4fun
11-12-2012, 04:34 PM
Looks like a bad power cord was the problem. After the fuse blew I got out the DMM and did a little testing. After replacing the fuse I read about 7v, so I replaced the cord. Is it possible I damaged the radio running with the crazy power? The noise seems to have cleared up with a new power cord, but I have yet to talk to anyone more than a half mile away. I just don't know if I'm getting out very well.

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ducksoupe
11-12-2012, 05:43 PM
remove the coax from the radio , DO NOT KEY MIC !!! with the radio on , if you still have the noise it's not comming from the antenna or coax but through the power lines . then you will know where you need to work on eliminating the noise at . Thats a suggestion I will keep in mind . My base is in the house and when I PLUG ANOYHER CORD IN MY POWER STRIP FROM ANOTHER OUTLET i GET NOISE

BOOTY MONSTER
11-12-2012, 06:33 PM
glad you found the right end to be working on :)