Horizontal Loop Antenna

Center Frequency 	Total Length in feet
3.5 MHz 	        287
3.6 	                279
3.7 	                272
3.8 	                264
3.9 	                258
7.0 MHz 	        143
7.2 	                139

Center Frequency 	Total Length in feet
10.12 MHz 	99
14.0 MHz 	72
14.2 	70
18.12 MHz 	55' 6"
21.0 MHz 	48' 10"
21.2 	47' 6"
24.93 MHz 	40' 4"

Center Frequency 	Total Length in feet
28.0 MHz 	35' 10"
28.5 	35' 3"
29.0 	34' 8"
29.5 	34' 1"

table from http://www.radioworks.com/nloop.html

Pie R Square

A = πr2

mmmm pie

A horizontal loop antenna for 80m that uses 287 ft of wire presumably has a circumference of 287' giving a calculated diameter of 91 1/4' or 45 1/2' radius. The area covered is just under 944'.

try https://www.omnicalculator.com/math/circumference

Length of a full-wave 80-meter loop is about 270 feet long (1005 divided by frequency in MHz)

If you make it a square instead of a circle then you have 67' sides.

Length of a full-wave 80-meter loop is about 270 feet long (1005 divided by frequency in MHz)

ref: http://www.k5rcd.org/hor%20loop%20instruct.htm