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Message |
    
Alabamakid
New member
Username: Alabamakid
Post Number: 2
Registered: 1-2005
| | Posted on Sunday, January 30, 2005 - 2:36 pm: | 
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On my mobile set up my swr is reading 3+ on all channels. I know that this indicated a short, but the cort is not in the antenna. I have verified this with a multimeter. When ever the coax is attached to my antenna it shows contiuity between my antenna shaft and the mounting bracket. If i disconnect the coax the continuity is not there. With the coax connected to the radio I get continuity between the center pin and the mounting bracket of the antenna. I know the coax is good. Any help would be greatly appreciated. |
Kid_vicious
Intermediate Member
Username: Kid_vicious
Post Number: 194
Registered: 9-2004
| | Posted on Sunday, January 30, 2005 - 4:54 pm: |
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how do you know the coax is good? does it show no connection between center pin and the braid when not connected to anything? sure sounds like a bad piece of coax to me. whenever im "sure" its not something, i test it anyway. go to rad shack, buy a premade jumper, and test the system with it. if it now works, throw the RS cable away (very lossy), and get a length of good stuff from copper. just how "sure" are you?
matt |
Sonoma
Intermediate Member
Username: Sonoma
Post Number: 155
Registered: 11-2001
| | Posted on Sunday, January 30, 2005 - 5:29 pm: |
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you say you are getting continuity between the antenna and mounting brkt.if you are it is shorted you should not have coninuity at these points.the brkt grounds to the body and where the antenna screws on it should not be grounded.as Matt said something is not right. |
Alabamakid
New member
Username: Alabamakid
Post Number: 3
Registered: 1-2005
| | Posted on Sunday, January 30, 2005 - 5:46 pm: |
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1. I have tested it several times.
2. I have replaced it with known good co-ax that has been tested
3. My SWR's are 1.2:1 when I put the 102" SS on
But even with the 102" SS I am showing continuity between the whip and the mounting bracket. Although, if I disconnect the coax the continuity between the antenna and the tool box is gone.
I have swapped out 3 different pieces of coax that all tested good with the multimeter.
I truely don't know |
Alabamakid
New member
Username: Alabamakid
Post Number: 5
Registered: 1-2005
| | Posted on Sunday, January 30, 2005 - 7:31 pm: |
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Sonoma--I only have continuity between the antenna and mounting bracket if the coax is on and connected to the radio. |
Sonoma
Intermediate Member
Username: Sonoma
Post Number: 157
Registered: 11-2001
| | Posted on Sunday, January 30, 2005 - 7:54 pm: |
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if you are getting a low swr on a 102 whip that is good.what antenna are you trying to use and where is it at on the body?I have a s10 truck and if I try to put a antenna behind the cab I get a high swr except for a 102 whip.the only 4 ft antenna I could use was a 4 ft k40 fiberglass that is a flexible antenna.the part number is sf400.it has a tunable tip on it.k40 calls it a super flex antenna.you say the antenna has continuity to the brkt.I am thinking you are checking where the antenna screws into the brkt.there should be a plastic spacer that goes between the antenna brkt and the stud where it mounts on the brkt then you screw the antenna into the stud and then the coax onto the other end of the stud.I am still thinking it may be the location and the antenna you are trying to use.
this is all I can help you with as to the info I have read on your notes.
Sonoma |
Kid_vicious
Intermediate Member
Username: Kid_vicious
Post Number: 201
Registered: 9-2004
| | Posted on Sunday, January 30, 2005 - 8:09 pm: |
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if your 102" whip gives you a low swr and the voltmeter says that the whip is shorted to the body, then i would suspect the voltmeter as being bad. |
Alabamakid
New member
Username: Alabamakid
Post Number: 6
Registered: 1-2005
| | Posted on Monday, January 31, 2005 - 7:57 am: |
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Sonoma the antenna that I am having trouble with is a wilson trucker 5000. It is mounted on the tool box in my pick up. I have checked continuity on the wilson from the very bottom to the top of the stinger. I have also put a longer stinger on it.
With the 102" I do have a low swr, on the dead key, when I modulate the ANT light on my radio comes on.
I have taken the mounting bracket several times just to double check the installation. I have the spacer in there.
Every thing checks out good until I plug the coax into the radio. When I have it all hooked up and the radio on my antenna (the wilson and the 102") chow continuity with every ground on my truck. Even the NEG. Batt. terminal. I can also unplug the coax from the antenna and the center pin will also show continuity with every ground on the truck.
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Sonoma
Intermediate Member
Username: Sonoma
Post Number: 159
Registered: 11-2001
| | Posted on Wednesday, February 02, 2005 - 12:11 pm: |
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OK now this helps a little more.1st off on most radios if you check for continuity at the radio with the power hooked up you will show about 1000 ohms.
what kind of radio do you have?
the wilson 5000 only has a 5 inch and 10 inch shaft and in most cases behind the cab it has so much reflect bouncing off the cab you can not get the swr to drop. on the 102 whip are you putting the spring on the bottom it needs this to help drop the swr.since the ant. is on the tool box how far is it,the antenna, from the cab.also do you have a bed liner in the pickup ?that can cause you to lose some reflect for a ground plane.you say you have continuity tell us what ohms it is reading.are you using a digital meter or analog.and put them on the lowest setting to read them for grounding.check the swr when you talk, you say the antenna light comes on.all swr goes higher when you talk,this is normal but let me know how high it goes .I have seen cobra 29 s antenna light come on on dead key with low swr due to it beeing out of adjustment from the factory.
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Alabamakid
Junior Member
Username: Alabamakid
Post Number: 11
Registered: 1-2005
| | Posted on Friday, February 04, 2005 - 7:37 am: |
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I have a cobra 29 LTD. The Wilson 5000 Has the 10" shaft on it. The antenna is appprox. 18" from the back of the cab. I don not have a bed liner, though I do have a rubber mat that lays in the bed of my truck. The multimeter that I am using is digital, its a cheapo from radio shack. The 102" has a 6" spring under it. As far as the SWR goes when I talk it doesn't goe avobe 2.1:1 when I talk, but the antenna light still comes on. |
Sonoma
Intermediate Member
Username: Sonoma
Post Number: 163
Registered: 11-2001
| | Posted on Saturday, February 05, 2005 - 11:10 am: |
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the problem I have had with a short shaft antenna behind the cab is reflect from the rf causing swr to go high.vr6 is adjusted too tight.the light should not come on at 2.I do not remember which way to turn vr6 to adjust this but a 2 swr is not going to hurt the radio.what I would do is pull the cover on the radio and hook it up and talk and turn vr6 just to the point the light goes out.almost all swr will go up when you talk into the radio that is fairly normal.with the speaker cover off and the radio knobs facing you vr6 is to the rt rear of the radio. |
Therealporkchop
Intermediate Member
Username: Therealporkchop
Post Number: 131
Registered: 11-2002
| | Posted on Saturday, February 05, 2005 - 1:36 pm: |
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Maybe it's the mount the coax connects to. Is the plastic washer still there? Maybe it's a short in the connector itself, not sure what they call it, a so-239 or something like that? |
