80/75 Meter 4-Square Array |
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| This array has been in use since 1989.
The SWR from 3.5 to 3.9 is below 1.5:1
The F/R of the array is 20dB average and with some signals even better. |
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| | View of the 4-Square from the top of one of my towers. (Approx 125 feet high)
The radial system consists of 90 1/4 wave long wires attached to the base of each vertical. |
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| | Close-up picture of the support post and base of the vertical.
Each vertical is mounted on a 6 inch square by 12 foot long pressure treated post.
The posts were buried 4 feet in the ground. |
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| | Construction Detail (Revised 4-14-2001)- The verticals are 65' tall. 40 feet of 4" and 25 feet of 3" aluminum irrigation tubing. The joint overlap is 1'.
- I have replaced the UV resistant bale twine (guy ropes) with 3/16" (770lb. tensile strength) UV resistant Dacron rope.
You can also find this image on page 9-57 of ON4UN's - Low Band DXing Book, 3rd edition.
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CLICK TO ENLARGE (File Size 100K) | | Support Post Detail (Revised 4-14-2001)- Each support post is 6" x 6" x 12' pressure treated. 4' of the post is in the ground..
- The vertical is insulated from the post by PVC electrical conduit.
- The support arms are made from 1/2" thick Plexiglass (Acrylic) sheet.
You can enlarge the image by clicking on it OR download a Windows MetaFile version by CLICKING HERE.
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| | Joint Construction Detail (Revised 4-14-2001)- I used a 1 foot overlap at the joint between the 4" and 3" tubing.
- 3-1/2" Sch. 40 Aluminum conduit (pipe) has to be machined to fit inside the 4" irrigation tubing.
- 3" Sch. 40 aluminum conduit (pipe) is used to transition from the 3-1/2" conduit to the 3" irrigation tubing. No machining required on this sleeve.
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| | THUNDERSTORM!! Check out these pictures of a thunderstorm that was a bit too close for comfort. Fortunately the cell didn't move directly over the array. It sure came close though. |
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