12-10-2013, 09:06 AM
I made some measurements of the materials used in the construction of this shielded antenna. They are:
Part Number 38-9881
Oval Forms are 4 ½ X 6 7/8 inches and have an approximate 18 3/8 inch circumference.
Paper used is 17 inches tall by 20 inches wide to provide about 1 inch of overlap when formed to fit the oval end pieces. The wires are about no. 29 bare copper wire and there are 65 strands. The wires are spaced approximately ¼ inch apart over a 16 inch axial distance. The spacing is not completely uniform. The wires are parallel from side to side across the 20 inch width dimension.
20 inches X 66 = 1320 inches = 110 ft. for tolerance allowance. The wire could be no. 28AWG or no. 30AWG. The bare copper wire strands are soldered to the copper tape about 1 inch from one end. The other ends of the wires are free. They are not a complete coil as described in the US Patent 2273955. The completed paper/wire assembly is either stapled together or stitched together in the required oval shape. The paper/wire assembly needs to be fit around the oval shape to insure that it slips over the wooden oval forms without damaging the paper as it slides over the wooden oval forms.
I think I will try my hand at constructing one using new paper and wire.
Joe
Part Number 38-9881
Oval Forms are 4 ½ X 6 7/8 inches and have an approximate 18 3/8 inch circumference.
Paper used is 17 inches tall by 20 inches wide to provide about 1 inch of overlap when formed to fit the oval end pieces. The wires are about no. 29 bare copper wire and there are 65 strands. The wires are spaced approximately ¼ inch apart over a 16 inch axial distance. The spacing is not completely uniform. The wires are parallel from side to side across the 20 inch width dimension.
20 inches X 66 = 1320 inches = 110 ft. for tolerance allowance. The wire could be no. 28AWG or no. 30AWG. The bare copper wire strands are soldered to the copper tape about 1 inch from one end. The other ends of the wires are free. They are not a complete coil as described in the US Patent 2273955. The completed paper/wire assembly is either stapled together or stitched together in the required oval shape. The paper/wire assembly needs to be fit around the oval shape to insure that it slips over the wooden oval forms without damaging the paper as it slides over the wooden oval forms.
I think I will try my hand at constructing one using new paper and wire.
Joe
