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Saturday, January 19, 2013

TV antenna as 2 Meter! (old text file)

This is an old newsgroup Text Info file! I just wanted to share what I can find from these lost archives Have fun!

Do you have an old (or new) VHF/UHF TV yagi you'd like to put to a little more 
exciting use than TV reception?  That antenna could be converted for scanner 
use with out too much trouble, and also be used to transmit 2 meter Amateur 
Radio.  The un-modified antenna could be used without modification, but images 
and signal overload from TV broadcasters could be a problem.   With the 
elements of the antenna unfolded to their normally extended positions, mark the 
longest elements (the hindmost elements) with a felt tip marker 21" from the 
boom, and the shortest elements (the foremost elements) at 16&1/2" from the 
boom. This should be done on both sides of the boom. After marking them, tie a 
string snugly from the mark on the rear boom to the mark on the fron boom as a 
cutting guide. Mark the remaining elements where the string touches them. 
Carefully cut off the excess lengths at the marks. The corner reflector (UHF) 
is modified as follows. Measure and cutoff all the corner reflector elements to 
16" lengths (total length). Saw off the boom directly in front of the closest 
element to the corner reflector (ie. leave one of the elements that is attached 
directly to the boom). This element will be the one connected to the feed line. 
The conversion is now complete.   Determine the new center of gravity and drill 
a couple of new mounting holes. Remember that the antenna will be mounted 90 
degrees from its normally horizontal polarization, so that the elements are 
oriented vertically. If you can, feed the antenna with RG-8U. The antenna will 
need a 300 ohm feed, so a proper transformer will be required at the feed 
point. The antenna should be mounted on a 3' length of PVC pipe to prevent the 
mast from interacting with the elements. Although the antenna will exhibit gain 
and directivity at VHF and UHF, do not expect much in the 30-50 Mhz range. Good 

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