[TowerTalk] Height For Horizontal Loops

[Thomas F. Giella NZ4O]

Dave in my personal experience the length of the loop determines the TOA of 
the RF as much as height above ground.

I use an 80 meter full wave loop (288 feet) for 80-10 meter operation. It's 
fed with 300 ohm window line to a balanced tuner. It's in a square 
configuration and each of the four corners is 35 feet above ground. 
http://www.wcflunatall.com/kn4lf92.htm .

Per EZNEC 5.0 modeling, on 80 meters the TOA is a straight up 90 deg., but 
at 3 db down there is some radiation at a TOA of 45 deg. I assume that the 
RF TOA is there or somewhat close to there as I can work out to 
approximately 5000 miles using 400 watts PEP.

Per EZNEC 5.0 modeling, as follows are take off angles of the lobe with the 
highest current point for each band as well as feed point impedance.
80 meters- 90 degrees, 3db down 45 degrees. 65 ohms

60 meters- 90 degrees, 3 db down 44 degrees. 3663 ohms

40 meters- 44 degrees. 275 ohms

30 meters- 35 degrees. 285 ohms

20 meters- 27 degrees. 265 ohms

17 meters- 21 degrees. 400 ohms

15 meters- 18 degrees. 400 ohms

12 Meters- 15 degrees. 370 ohms

10 meters- 11 degrees. 250 ohms

In my case having the antenna up at only 35 feet works very well for DX on 
40-10 meters.

73 & GUD DX,
Thomas F. Giella, NZ4O
Lakeland, FL, USA
nz4o at arrl.net

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