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Antenna Problems

WSCU736

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WSCU736 Contributor

WSCU736

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I have a Comet-EFC. I have no receive signal at all. I tried 2 different radios with the same result. I used a multimeter set on ohms. From radio coax I tested center pin and the ground with coax connected to the antenna. And I get a OL on the meter. I have no clue what is wrong. I think the antenna is bad. Please help.

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SteveShannon Grand Master

SteveShannon

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4 minutes ago, WSCU736 said:

I have a Comet-EFC. I have no receive signal at all. I tried 2 different radios with the same result. I used a multimeter set on ohms. From radio coax I tested center pin and the ground with coax connected to the antenna. And I get a OL on the meter. I have no clue what is wrong. I think the antenna is bad. Please help.

I doubt that the antenna itself is bad. It’s much more likely that the coax or a connector is bad. Do you have a different piece of coax to try?
You know that the shield and center conductor are not shorted together when measured from the radio end. That’s good. 
Take the coax off the antenna and see if there’s continuity from one end of the center conductor to the other end of the coax. There should be. 
Do the same for the shield. It should show very little resistance from end to end. 
Let us know what you find. 

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Socalgmrs Mentor

Socalgmrs

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9 minutes ago, WSCU736 said:

I have a Comet-EFC. I have no receive signal at all. I tried 2 different radios with the same result. I used a multimeter set on ohms. From radio coax I tested center pin and the ground with coax connected to the antenna. And I get a OL on the meter. I have no clue what is wrong. I think the antenna is bad. Please help.

Might be.  Might be coax still.  With out an antenna analyzer it will be hard to tell. Can you test both sides of the center pin and make sure you have continuity that way first?  
 

you say you dint have rx.  Do you have tx? 

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WSCU736 Contributor

WSCU736

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6 minutes ago, SteveShannon said:

I doubt that the antenna itself is bad. It’s much more likely that the coax or a connector is bad. Do you have a different piece of coax to try?
You know that the shield and center conductor are not shorted together when measured from the radio end. That’s good. 
Take the coax off the antenna and see if there’s continuity from one end of the center conductor to the other end of the coax. There should be. 
Do the same for the shield. It should show very little resistance from end to end. 
Let us know what you find. 

If I gett on the roof the wife would kill me. I am retired besause of 7 spine surgeries. I will try and get someone to take it down.

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SteveShannon Grand Master

SteveShannon

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11 minutes ago, WSCU736 said:

If I gett on the roof the wife would kill me. I am retired besause of 7 spine surgeries. I will try and get someone to take it down.

Yeah, don’t do that. 
Did this just suddenly happen or was it gradual?

Have you had much rain lately?  Moisture can ruin the ends of coax. 

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WRKW566 Contributor

WRKW566

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1 hour ago, WSCU736 said:

I have a Comet-EFC. I have no receive signal at all. I tried 2 different radios with the same result. I used a multimeter set on ohms. From radio coax I tested center pin and the ground with coax connected to the antenna. And I get a OL on the meter. I have no clue what is wrong. I think the antenna is bad. Please help.

Skip all this, I see you found your problem before I could stop typing my long noisy post :)

 

The spec sheet on that antenna reads like nice equipment. I would try some process of elimination stuff before going to the trouble of pulling down that antenna. First, do the two radios "talk" to one another with the stock antenna(s)? Be sure you are testing with a simplex channel and not a repeater channel. Second, open the squelch on one of the radios and with the stock antenna, listen for traffic on the band. Check all of the non repeater channels. If you can hear someone then go back to the big antenna ans see if they are still there.

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WRYZ926 Mentor

WRYZ926

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37 minutes ago, WSCU736 said:

Another update. I finally got my SWR meter. And checked my SWR and it was 1.2 on channel 16 and 1.7 on channel 30. And I have 85' of a coax run.

Those numbers are perfectly fine. It is quite normal to see a slightly higher SWR on the repeater channels since they are 467 MHz versus 462 MHz. The SWR on channels 8-14 will probably be around 1.7 also since they are 467 MHz. And good for you on using LMR400 instead of some cheap RG8 from Amazon.

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