Measurements for building a full wave loop using wire

The measurements below are for building a full wave loop using wire . The wire size may range from 16 AWG to 12 AWG . The lower the wire number the greater the bandwidth . For example 12AWG will have a lower swr ( Standing Wave Ratio ) over a greater frequency range than 16 AWG .

The measurments below are in feet and inches . I have rounded off some of the measurments so it will be easier to measure them .

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The diagram below is a representation of a ( Full Wave Loop ) . A flat top has a feed point impedence of about 150 ohms .

The yellow line is a one full wavelength antenna .

The red line ia a representation of a support to hold the antenna above the ground .

The orange center is the representation of the coax connection . The center conductor of the coax connects to one end of the continuous piece of wire , and the shield of the coax connects to the other .

The drawing on the left , is when you feed the loop antenna in the center the antenna takes on a horizontal radiation pattren , but when you feed the antanna in the corner , like the drawing on the right , the antenna takes on a vertical radiation pattreen .

 

 

The formula for figuring a full wave loop is ” length = 1005 divided by the frequency in megahertz .

The formula for figuring the quarter wave coax transformer is ” length = 251 divided by the frequency in megahertz times the velocity factor of the 75 ohm coax you desire to use .

Example

Length of quarter wave transformer 92FT. = 251 divuded into 1.8 MHZ. (Times) .66 for the RG11 A/UOne end of the coax that attachs to the antenna , and the other end where you install a PL259 connector . From there you may install a barrel connector and any length of 50 ohm coax to get the antenna connected to the tranmitter .

 

Operatings Frequency	Full Wave Loop Antenna Length	1/4 Wave Coax Matching Transformer Length ( RG-11A/U )
160 Meters
1.8 Mhz.	558′ 4″	92 Ft.
1.9 Mhz.	528′ 11 3/8″	87′ 2 1/4″
2 Mhz.	502″ 6″	82′ 10″
80 Meters
3.5 Mhz.	287′ 1 3/4″	47′ 4″
3.6 Mhz.	279′ 2″	46′
3.7 Mhz.	271′ 7 1/2″	44′ 9 1/4″
3.8 Mhz.	264′ 5 3/4″	43′ 7 1/8″
3.9 Mhz.	257′ 8 1/4″	42′ 5 3/4″
4 Mhz.	251′ 3″	41′ 5″
60 Meters
5.4 Mhz.	186′ 1 1/4″	30′ 8 1/8″
40 Meters
7 Mhz.	143′ 6 3/4″	23′ 8″
7.1 Mhz.	141′ 6 1/2″	23′ 4″
7.2 Mhz.	139′ 7″	23′
7.3 Mhz.	137′ 8″	22′ 8 3/8″
30 Meters
10.1 Mhz.	99′ 6″	16′ 4 3/4″
10.15 Mhz.	99′	14′ 10″
20 Meters
14 Mhz.	71′ 9 1/4″	11′ 10″
14.1 Mhz.	71′ 3 1/4″	11′ 9″
14.2 Mhz.	70′ 9 1/4″	11′ 8″
14.3 Mhz.	70′ 3 3/8″	11′ 7″
17 Meters
18.068 Mhz.	55′ 7 1/2″	9′ 2″
18.130 Mhz.	55′ 5 1/8″	9′ 1 9/16″
15 Meters
21 Mhz.	47′ 10 1/4″	7′ 10 5/8″
21.1 Mhz.	47′ 7 1/2″	7′ 10 3/8″
21.2 Mhz.	47′ 4 7/8″	7′ 9 3/4″
21.3 Mhz.	47′ 2 1/8″	7′ 9 3/8″
12 Meters
24.890 Mhz.	40′ 4 1/2″	6′ 7 7/8″
24.950 Mhz.	40′ 3 5/8″	6′ 7 5/8″
10 Meters
28 Mhz.	35′ 10 13/16″	5′ 11″
28.5 Mhz.	35′ 3 1/8″	5′ 9 3/4″
29 Mhz.	34′ 7 7/8″	5′ 8 1/2″
29.5 Mhz.	34′ 0 3/4″	5′ 7 3/8″

Original Article By N8ITS hosted at  home.comcast.net/~n8itf/floop.htm