Help Mounting 2 mtr mobile antenna

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Posts: 4
Joined: Sat Jul 15, 2006 9:35 pm
Location: Georgia

Help Mounting 2 mtr mobile antenna

Post by KA4UPI » Mon Aug 27, 2007 1:09 am

I am attempting to mount a Larsen 5/8 mobile antenna on my F250 truck just behind the tool box on the passenger side. For the life of me I can not get the thing anywhere near resonate to 147.85. My MFJ 259B says that it is most resonant at 175.85 with about 1.7 swr. The swr at the target freq. is 4 to 1. I have moved it, raised it, shortened it, grounded it, and cursed it to no avail. Could anyone please give me some tips on how to best to approach this. Should I look at maybe shorting the coax some? At one point I did have it near 1.1 swr while in a temporary connection before soldering the PL259 and acutually mounting the base on an extended aluminum bracket just behind the cab. Any pointers welcome. KA4UPI.

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Post by wa4cch » Mon Aug 27, 2007 2:33 am

hi unscrew the ant from the mount and check the coax for a short


Posts: 30
Joined: Wed Jul 18, 2007 1:16 am
Location: Kennedy NY

antenna shorted

Post by w2rdt » Mon Aug 27, 2007 9:25 pm

Hi, over the years, I have seen many defective antennas fixed by
removing pl-259 and making sure that NOT EVEN one strand of
the braided shield is contacting center conductor. This will give
you the problems your having. If you have a dummy load, you can
check your feed line by putting a barrell connector on the coax at
the antenna end to verify a 1-1 match.
Good luck

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