Question about Cobra 148 GTL 120-Channels Base CB Radio

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Saturn workman b-100

SWR is way too high using b-100 in attic with 148 gtl.This is a no ground plain antenna with bracket screwed into a wooden truss.Is there any way to tune the antenna as I thought no tune was needed.

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I just bought this antenna and i saw that swr was off the scale so i was thinking and thought of trying a ground on the bracket of the antenna and when i did that the swr's were totally flat. When i did that i called my buddy and told him to let me know what the signal was with this antenna and he said it was like 91/2 pounds for signal and that was with it in my bedroom. so i would just put a ground wire on the bracket andyou would be good.

Posted on Jan 18, 2009

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Hi,

I read through the specifications of this antenna and you were right in posting "no ground plane, no tune". Still, there are only three (3) possible reasons why the SWR would be high:
1. Cable/connector - loose, cold solder or improperly terminated;
2. Antenna - tuning and/or ground plane; and
3. Radio has been highly modified or defect in final stage.

Corrective procedures would call for:
a. verify that the coaxial cable is properly connected to the PL-259 connectors. You may need to use a continuity tester (or a DVM) to do so. Pls pay particular attention to the braided shield/grounding, they should be real tight/soldered good to the casing of the connector. Of course the cable should be 50ohms RG8 or 58 with thick shielding.
b. as stated the antenna doesn't need to be tuned then there's nothing that can be done since there is no provision for such, however, even if the specs says no ground plane needed, there is something you can try. Install a ground plane. this could be done by attaching 2 lengths of big gauge ordinary wire to both sides of the metal bracket of the antenna. They have to be 8' 7" ~ 9' long. It may help you further to install a grounding strap again from the metal bracket to any grounded metal portions of your house such as the plumbing.
c. radio problem would be unlikely if it is still stock.

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

Good luck and kind regards.

Posted on Feb 07, 2008

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Remember keep everything in lengths of 3 for good swrs

Posted on Feb 07, 2013

Spend 20 dollars more and get a 12 foot stick

Posted on Nov 08, 2008

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Hello everybody,try to use a 28 metres of coaxila cable rg58 and cut it untill the swr go down.I do that and the srw of my antenna is 1:1,2 on 27.285MHz till 27.585MHz.
73 and good luck
rick

Posted on Feb 02, 2009

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I had this same problem; I was using RG-8 with homemade connectors. My SWR was off the chart. I picked up 50' of RG-58 from Radio shack and the SWR needle hardly moved. So I guess I have to get better at soldering RG-8 connectors.

Thanks for the tip, its much appreicated.

Posted on Sep 30, 2008

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I am having a problem with mt cb. I used all new coax, antenna, antenna stud and mount. New mic and radio. The problem is I hook up the swr meter, keyed and the meter swung hard right. I have changed


ok, you have a high SWR.. this is what you can do.. you're gonna need to check the Radio's coax connection to see if it's loose on the Radio itself.. you're gonna have to open the Radio cover on the speaker side.. now go look at the connections on the pc board itself and see if there is a possible broke connection.. one is pcb ground, and one for the center. also, you might want to get a phillips head screw driver and gently tighten all the screws on the pc board. becareful going in there.. after this said and done, check the antenna connector itself to see if it's loose. if so, then you're gonna have to a pair of pliers to turn the nut on the inside while you use wrench to hold it in place on the outside.. now you're ready to test the radio.. don't put the cover on just yet until you see the results. set up your SWR Meter to the Radio and then set up the dummy load and do a SWR Test. if the reading is good, then the Radio is all set.. now for the Antenna.. you said that it's all new, but regardless you need to test it too.. check both ends of the cable and do a condinuity test.. get a ohm meter that has an audio sound. this will help you.. set the meter to ohms/conditnuity.. then short out the probes to get a ZERO reading/audio sound.. now take one end of the of the cable and put the probes on the connector.. one probe for the outter ground shell and the other probe to the center pin connection. if you see a ZERO reading or an audio sound, that means you have a short in the cable.. another way is to do it end to end.. put one probe on one end of the cable, and the other probe on the other end.. test the ground side first.. if you get a sound or a ZERO reading, that means you may have a short in the cable itself and may requier to remove the connectors.. some cases you might have to replace them.. remember to calibrate your meter when testing let me know how it goes.. I'll continue to help you.. you can contact me on Facebook.. https://www.facebook.com/pages/ANR-Communications-Repair/136358796473669?ref=bookmarks Good Luck..

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Antron 99 is the smalles antenna that will fall into a near best category.

But the saturn B will still work if you absolutely need small. you can find a bunch on ebay cheap.

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Hi, my name is John. Welcome to FixYa. Check your antenna, you need to set it with a real SWR meter, pick one up at any near-by CB shack $10.00. Thanks for choosing Fixya...John

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Center the antenna on the vehicle, then check the SWR on channel 1 and channel 40.
with the switch in CAL position, key radio and use the swr/cal knob to set the meter so the needle is just touching the end of the red area on the right-hand side of the meter.
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if it dont transmit period on AM, then there's an internal glitch :)

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Hi,

It would seem that you posted twice. Here is the link to your other post.

If I may add to Mechanic688, sharcnet, chiaflub67 and Nitrotrike's postings (with their indulgence), below is a copy of my reply to the other post....

"I read through the specifications of this antenna and you were right in posting "no ground plane, no tune". Still, there are only three (3) possible reasons why the SWR would be high:
1. Cable/connector - loose, cold solder or improperly terminated;
2. Antenna - tuning and/or ground plane; and
3. Radio has been highly modified or defect in final stage.

Corrective procedures would call for:
a. verify that the coaxial cable is properly connected to the PL-259 connectors. You may need to use a continuity tester (or a DVM) to do so. Pls pay particular attention to the braided shield/grounding, they should be real tight/soldered good to the casing of the connector. Of course the cable should be 50ohms RG8 or 58 with thick shielding.
b. as stated, the antenna doesn't need to be tuned then there's nothing that can be done since there is no provision for such, however, even if the specs says no ground plane needed, there is something you can try. Install a ground plane. this could be done by attaching 2 lengths of big gauge ordinary wire to both sides of the metal bracket of the antenna. They have to be 8' 7" ~ 9' long. It may help you further to install a grounding strap again from the metal bracket to any grounded metal portions of your house such as the plumbing.
c. radio problem would be unlikely if it is still stock."

Regards all.

Jan 31, 2008 | Cobra 148 GTL 120-Channels Base CB Radio

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