SBGH Plan, Parts List, Cut List, and Construction Notes by 300ohm


Parts List
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2 - 10 foot pieces of 1/2" sch 40 600psi pvc pipe.
2 - 1/2" sch 40 pvc elbows.
1 - 1/2" sch 40 pvc cross.
17 - 1/2" sch 40 pvc tees. (Buy 2 contractor 10 packs)
30 - Nylon wire ties. (Buy a 50 pack)
36 - 1/2" x #6 plated wood screws. (Buy a 50 or 100 pack)
2 - 5 foot pieces 6 gauge solid copper wire. (This is $.84 a foot at Lowes. Buying just one 5 foot piece of 10-2 solid wire and stripping it will save approx 60% and is stiff enough with the stub holders.)
1 - 30" by 40" 10 gauge piece of fencing, 2" X 4" grid or less. (1" x 2" would be ideal as it would give about 1/4 db more gain at channel 17, about 1/2 db more at channel 40, but it would decrease my chances of reception of channel 36 Atlantic City about 180 degees east)
2 - 1 1/4" ID u-bolts to clamp antenna to mast.
4 - #10 x 1" stainless or brass pan head screws.
2 - #10 x 1 1/2" brass bolts. (for least galvanic corrosion at connection point)
4 - #10 brass nuts.
10 - #10 brass or copper washers.
1 - Tube Plumbers Goop. (Or Loctite Plumbers and Marine Adhesive or plumbing PVC cement or epoxy or even plastic model glue, this is antenna work not plumbing.)

Miscellaneous and Beauty
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4 - Sch 40 pvc caps.
1 - Can of flat black spray paint.
1 - 300ohm to 75 ohm balun
Length of RG6 cable and ends to suit.


Cutting List
===========================
A) 4 pieces @ 3 7/8"
B) 4 pieces @ 8 1/2"
C) 4 pieces @ 3 5/16"
D) 4 pieces @ 4" * (These stub holder pieces are just pushed in, not glued or screwed.)
E) 2 pieces @ 37 9/16"
F) 2 pieces @ 8 3/8"
G) 2 pieces @ 8 3/4" # (This gives a 10 inch (254mm) spacing between element inside angles)
H) 6 pieces @ 2 3/8" *
I) 3 pieces @ 1 3/4" # (This gives a reflector to element spacing of 100mm)

>>>>>>>>>>> Push all pipe into fittings 5/8" <<<<<<<<<<<<<<<

# = Critical Size
* = Not a Critical Size

I havent yet priced all the items, but I figure its somewhere about $25 if everything had to be purchased. My out of pocket costs were only about $12, as I had a lot of the stuff. The Channel Master 4221A would cost me $23.99 plus 15.95 UPS ground shipping for a total of $39.94 from SolidSignal. But wheres the fun in that ?????


Construction Notes


Construction Notes
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I predrilled with a 3/32" drill bit, the holes for the 1/2" #6 plated wood screws. All screws were attached to the fittings on the backside, ie the reflector side, to minimize the effect of the screws on the antenna. (see picture) No screws were used for the building of the cross-pieces, they were glued. No screws were used for the "stub" holder, its just a press fit (its not going anywhere).

I predrilled with a 1/8" drill bit, the holes for the 1" #10 stainless pan head screws in the top and bottom cross-pieces. The element rests on the plastic and there is a brass washer between it and the pan head of the stainless steel screw.

I predrilled with a 3/16" drill bit, the holes for the #10 x 1 1/2" brass bolts in the middle cross-piece. The element also rests directly on the cross-piece, then a brass washer, then a brass nut is used to secure the element. Then 2 brass washers and a brass nut are attached for connecting the antenna balun between those 2 washers.
The holes on each cross-piece were drilled centered, on the cross-piece exactly 100mm apart (50mm on each side of center). This gives an air space between the wires of 88mm (93mm center of wire to center of wire) using 6 gauge solid copper wire. (Using 10 gauge wire will widen the distance)

Bending Jig
====================



I used that scrap piece of wood to keep the rest of the antenna flat while bending it around the nail. (6 gauge solid copper wire is pretty tough to work with, glad I didnt use 4 gauge, heh)
For the cross-piece jig, so that the cross-pieces would be perfectly aligned, I made a crude version of Bix2's cross-piece jig pictured earlier in this thread.
And that full sized drawing on scrap cardboard of one of the antenna elements came in very handy.
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SOURCE:   http://www.digitalhome.ca/forum/showthread.php?t=95898

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