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SWR all over the map.

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Old 01-01-2015, 02:32 PM
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Default SWR all over the map.

What would cause the readings to be very low say 1.1 on both 1 and 40 one minute and check again a minute later and both will be over 3. I won't change a thing and retest and back down low retest again and back up high. thanks
Old 01-01-2015, 02:35 PM
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Make sure you are not in a garage and in an open area when testing and that all the doors and tailgates are shut.
Old 01-02-2015, 01:44 AM
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What are you using to measure SWR?
Old 01-02-2015, 03:50 AM
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in empty parking lot with lots of space from buildings. SWR is measured with a radio shack meter.
Old 01-02-2015, 04:31 AM
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Possibly a bad connection or antenna. Have someone watch the meter while you tweak and twist cable at each connector. Be sure to do this at the cable you use to connect meter into circuit Also move antenna around, checking for same thing. But be aware that SWR will move as you touch antenna, so try tapping on it or flipping it a little to see if it is your touches or perhaps damage (caused by hitting too many trees in my case, LOL).
Old 01-02-2015, 07:52 AM
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ok this morning I can not get it to change. 1.1 on 1 and 1.5 on 40. it is a brand new 4' firestik II on a TF mount. I had been running a 3' firefly but was not really happy with the reception. I have to wait until my wife gets home from work to jiggle the connection at the tailgate. I do not have the coax coiled tight I have the extra length in a large loop.
Old 01-02-2015, 08:02 AM
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Because of the way the SO-239/PL-259 connectors are designed with that little sawtooth section to keep them from rotating, it's possible to get it where you didn't have it seated all the way. Perhaps removing and reinstalling the meter changed things the next day? Just a thought.
Old 01-02-2015, 08:34 AM
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Originally Posted by Mark Doiron
Because of the way the SO-239/PL-259 connectors are designed with that little sawtooth section to keep them from rotating, it's possible to get it where you didn't have it seated all the way. Perhaps removing and reinstalling the meter changed things the next day? Just a thought.
I did make sure that the teeth were fully engaged as that was my first thought. I actually left the meter hooked up so that is why it is so perplexing.
Old 01-02-2015, 11:26 AM
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Another place to check is where the cable bends at the tailgate hinge. I've found two different friend's had the bend too tight. It can damage the cable internally--minimum bend radius for coaxial RF cable is about 8 times its diameter.
Old 01-02-2015, 12:02 PM
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Originally Posted by Mark Doiron
Another place to check is where the cable bends at the tailgate hinge. I've found two different friend's had the bend too tight. It can damage the cable internally--minimum bend radius for coaxial RF cable is about 8 times its diameter.
not sure if in the photo you can see the bend but is pretty mild (have the copper colored coax with clear sheath) and the cable is only contacted by the rubber on the window and moves freely in and out. it is crazy I can not get it to go high right now which I guess is a good thing. I have it tuned with channel 40 on 1.4 and 1 on 1.2 and going to leave it like that until I get a chance to test it out. Only thing is now I am paranoid it will bounce back up to 3. I also tested it per firestik using my ohm meter and all is good. the photo makes it look like corrosion on top but I have the proper plastic spacer and oring and I have good contact on the bottom of the mount ie I filed the paint off the bottom so it is metal to metal.


Last edited by jadmt; 01-02-2015 at 12:10 PM.


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