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Analyzing KipKay's YouTube Antennas

9K views 30 replies 5 participants last post by  florida ham 
#1 · (Edited by Moderator)
Howdy DIY HDTV antenna enthusiast.

Has anyone built this YouTube antenna?
https://www.youtube.com/watch?v=X_OhW02DmUs

I picked up two 20x30 foam boards from a Micheal's Crafts Store here in town on sale for .99 cents each. I've got some Elmer's glue and aluminum foil and a staple gun and glue and a ruler, so it will be actually be a $2 HDTV antenna for me to build as I have a bunch of cable TV company coax laying around etc.

Was hoping maybe holl_ands could run it through that antenna modeling software he uses and see if thinks it's worth the effort and let everyone know what kind of gain if any this antenna would produce and what the SWR curve would be across the smaller HDTV band it would provide.

Thanks in advance for any contributions to this topic and or idea's.
 
#27 ·
Other than the original Kip-Kay version incorrectly designed for the 800-MHz Cellphone Band, there are TWO DIFFERENT LPDA Versions redesigned for the UHF Band.

Xauto's Revised Template (post #16) is a simple ReScale of Kip-Kay's NON-Optimized Dimensions so that it covers the UHF Band, as described in my post #10.

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My post #19 is for a Higher Gain, OPTIMIZED 7-El WEDGE LPDA, assuming Wire Radius = 0.2-in, which found a "Wedge" Angle of only 0.66-deg, which means the 0.5-in Boom-to-Boom Separation at the Feedpoint only grows to 0.71-in at the Rear.

So I reran the Optimization finding the "best" Boom-to-Boom Separation = 0.69-in (all along the BoomLength=18.6-in), for a 7-El Twin-Boom "LAYERED" LPDA configuration (post #20), using the SAME Dimensions as for the OPTIMIZED WEDGE. THIS is what you should build for the "Best" 7-El LPDA. Detailed dimensions are found in the 4nec2 files that I included in the above posts.

BTW: I assumed Wire Radius = 0.2-in since 4nec2 primarily uses ROUND wire models. I KNOW that a smaller Wire Radius should be assumed when trying to model FLAT Elements, such as the 0.5-in wide Elements used above. But it's always been somewhat unclear as to how MUCH smaller the Wire Radius would need to be to accurately model FLAT Elements. I plan to investigate this issue with some FLAT Antenna models in the near future to ascertain the requisite size derating ACTUALLY required.
 
#28 ·
Thank you holl_ands, Xauto and pips.

I'm posting a picture of a Silver Sensor antenna below because it's mentioned several times as something to compare the KipKay's DIY Antenna to but they are entirely different in so many ways, including materials, feed point, and the coax is fed to the larger elements first where as the KK feeds from the smallest elements forward to the largest ones.



I have seen several different versions of the Silver Sensor, ones with rabbit ear elements at the rear I guess for VHF reception and others that are amplified or both. It's a neat looking mouse trap, as you can see it's a double boom LPDA with tapering cord like wing elements that are swept back like the wings on a jet aircraft to make it's width narrower and make the antenna more of a conversation piece than, well rabbit ear antennas with a UHF Loop.
 
#30 ·
I have a Zenith labeled Silver Sensor just like the one shown above....and BTW mine has been knocked around so much the rear Coax Connector assembly has come loose from the rest of the Antenna, revealing that there is a Coax Cable running all the way to the FRONT of the Antenna, so the Feedpoint is the SAME as all of the other LPDA models shown here.
 
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