80/75
Meter 4-Square Array
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CLICK ON IMAGES FOR LARGER
VERSIONS
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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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CLICK TO
ENLARGE
(File
Size 100K)
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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.
CLICK HERE to download a
Windows MetaFile (.WMF) version of this drawing. (File Size 28K)
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CLICK TO
ENLARGE
(File
Size 100K)
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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.
CLICK HERE to download a
Windows MetaFile (.WMF) version of this drawing. (File Size 28K)
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CLICK
TO ENLARGE
(File
Size 100K)
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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.
CLICK HERE to download a
Windows MetaFile (.WMF) version of this drawing. (File Size 28K)
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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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4Square 80M
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