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Cobra 29 and 102 install

This is the place to post your general tips or ask questions about your installation, whether it's for mobile or base stations.
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Fireman
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Cobra 29 and 102 install

#225691

Post by Fireman »

I installed my cobra 29 today and antenna. I used a 102 with a spring. My SWR is high and varies i have grounded the antenna. i dont know if the coax running from the radio to the meter is too long? Also sometimes the radio speaker works and sometimes it doesnt.
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White Lightning
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Re: Cobra 29 and 102 install

#225879

Post by White Lightning »

Fireman wrote:I installed my cobra 29 today and antenna. I used a 102 with a spring. My SWR is high and varies i have grounded the antenna. i dont know if the coax running from the radio to the meter is too long? Also sometimes the radio speaker works and sometimes it doesnt.
How much coax are you running? you might have a loose wire going to the speaker inside the radio
2009 Silverado Ext Cab
Cobra 29 LTD Chrome 102' SS Whip
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Circuit Breaker
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Re: Cobra 29 and 102 install

#225884

Post by Circuit Breaker »

You can certainly have too much coax...but that won't (or shouldn't) affect the SWR. If it does, then there's something else wrong. How is this antenna installed? You may need to run more than one "ground" wire. The bed of my truck is made of a high impact plastic composite...no metal at all. When I installed my 102" whip, I had to add three "ground" wires to bring the SWR down. I have one attached to each corner of the mount closest to the cab and ran each one to the frame on each side of the vehicle. Then I added one more to one of the bolts holding the mount to the bed and connected that to the frame. Now my SWR is 1.0:1 from 26.000 to 27.405 when it starts to climb.
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Kenwood TR-751 2M all mode mobile
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Icom ID-92 HT
SteppIR 40-6M Yagi
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Diamond V2000A 6M/2M/70cm ground plane antenna
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626
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Re: Cobra 29 and 102 install

#225885

Post by 626 »

With questions like this there are many other possible issues. What kind of vehicle is it? Where is the antenna mounted? What kind of mount are you using with the spring, for example, ball mount? How are you measuring your SWR, and when you say your SWR is high what is the ratio, or number? Please describe how you "Grounded" your antenna.

Bad coax can cause your SWR to vary. The length of the Coax is inconsequential.

Try a different speaker. if that doesnt solve your problem then it may be a loose jack or a loose connection elsewhere inside the radio.

Let us know

GUNNY
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linx

Re: Cobra 29 and 102 install

#225891

Post by linx »

I'd also check the spring. Those things don't last forever. Sometimes they're bad brand new. It's just a really thin piece of braid that goes down the middle of the spring. That thing can break off easily.
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Re: Cobra 29 and 102 install

#226110

Post by Roper »

Good deal Fireman you finally got in :geek:
2011 Chevrolet Silverado Ext Cab Dually
Cobra 29 LTD Classic 102' SS Whip
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Re: Cobra 29 and 102 install

#226167

Post by Fireman »

Thanks for everyone ones reply and sorry it took so long to get back on, i cannot access this site at work. The antenna was mounted on the pass. side steak pocket closest to the cab, i moved it to the rear one and the SWRs have gone down. I have talked to several people on the radio and it is working great right now. Again thanks. Fireman
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White Lightning
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Re: Cobra 29 and 102 install

#226347

Post by White Lightning »

Now that's what I like hearing good job Fireman
2009 Silverado Ext Cab
Cobra 29 LTD Chrome 102' SS Whip
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