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Old 30-Jun-2012, 9:44 PM   #1
vienna01
Junior Member
 
Join Date: Jun 2012
Posts: 3
Need Help Assemblng Log Periodic TV Ant

As the title suggests, I really need help figuring out how to CORRECTLY assemble my TV antenna When I ordered it I expected to do some assembly, but all I got were parts. I decided to take on the challenge [a mistake]. The list of parts shows UHF dipole completely assembled !

In the attached photos/diagrams I show both some of the instructions that came with the “antenna” and some photos that I made.. From my experience 5 decades ago [true], I think this is called a log periodic antenna. I recall it would have active and reflector elements. The cover of instructions says: ” Two directors, two dipoles good receptivity”. UHF 21-99 470-860 36 Gain {db} impedance (ohms) 75.”

There are only three sizes of aluminum pipe loops. All the plastic parts that support the aluminum loops are identical for all three sizes. In my TRIAL assembly, I have only made the large loops touch [join]. The Large Loop is at the rear of the antenna.

I made only the large loops touch without any particular reason. For all the Small loops and the Medium loop, the 2 opposing aluminum pipe loops are not joined –they do not touch. These are about 2 inches apart.

I guessed that the medium sized loop was the active part of the antenna and the others were reflectors. There were 2 thin flexible metal strips that came out of the center rotator assembly [black plastic marked UHF]. I attached one of each metal strip to each side of the aluminum loops. The two sides of this Medium Loop are not joined-they are not connected,

The antenna has a rotor housing that might also include some electrical components. The rotor has a twin-lead type cable marked VHF and to metal strips on the other side marked UHF. The antenna came with a combined power supply booster that is to be connected to a 50 foot coax cable that is connected to the rotor. The power supply booster combo has three coax connectors marked, antenna, DVR and television. It has an on-off switch and a button that causes the rotor to turn. The antenna turns 360 degrees and then reverses itself.

My questions:

Which of the Small. Medium and Large Loops, if any, should touch in the center?

Should all the loops be isolated from the center square pipe?

If any of the loops need to be joined in the center [to form a closed loop] should I add a bit of wire to make sure they are well connected [joined in the center]?
Even when they are joined, they might separate a bit in the wind.

Should the metal strips be attached to the medium or to the large loop [I can do it either way ?
Attached Images
File Type: jpg 500-medium-loop-w-strips.jpg (81.4 KB, 802 views)
File Type: jpg 500-small-manufact-instruct#1.jpg (39.4 KB, 810 views)
File Type: jpg 500-small-loop-at-front.jpg (67.4 KB, 750 views)
File Type: jpg 500-small-instructions-#2.jpg (47.1 KB, 824 views)
File Type: jpg 500-small-Extra-View-How-Al-Strips-Attached.jpg (79.0 KB, 786 views)
File Type: jpg 500-small-looking-toward-front.jpg (91.5 KB, 804 views)
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