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Old 8-May-2015, 6:50 PM   #3
stvcmty
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Join Date: Mar 2013
Posts: 135
Quote:
Originally Posted by user name View Post
I rotated a 10 foot long UHF antenna 90 degrees and tried to use it as a VHF antenna but did not succeed.

Can a rotated 10 foot long (UHF only) antenna receive a VHF signal?
If I understand your question, you are asking: “If I try to use my antenna as a 10’ dipole, why didn’t it work?”


A 10’ dipole would be resonant at 46 to 49MHz, depending on velocity factor. TV channels don’t start until 54MHz, and there is not much full power DTV on channels 2-6, so the frequency that matters is 174MHz for channel 7 up to 216MHz for channel 13. A dipole resonant at 49MHz is not going to do much for channels 7 to 13.

The boom for your UHF antenna is most likely electrically bonded to ground through your mast. So for a sideways UHF antenna boom to act as a dipole antenna, the UHF antenna would need to be electrically floating relative to the mast, and it would need to have an insulator half way along its length. Then a wire could be attached to each side of the insulator and there would be a dipole in the boom.
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