N2HJD REPEATER MEGAPLEX, TECHNICAL INFO

Build a low cost dual band antenna for VHF/UHF (ARRL Feb 2003, written by Edison Fong, WB6IQN):
Download Article (theory, design & performance), 850K pdf

Build the improved "RRRA" dual band antenna for VHF/UHF (Design by Pete Schuch, WB2UAQ):
RG-8/U Dual Band J-Pole, 465K gif

The following is a table of common coax charactistics:

Attenuation ( dB ) / 100 Feet

Coax Type VP in % 50 Mc 100 Mc 200 Mc 400 Mc 1000 Mc Max. P @ 400 Mc
RG 174 66 5.8 8.5 12.5 19 34 12 W
RG 316 70 5.6 8.3 12 17.5 29 240 W
RG 58A/U 66 3.3 4.9 7.3 11.5 21.5 75 W
RG 58U 66 2.9 4.2 6 9.1 16.5 85 W
RG 142 70 2.7 3.9 5.6 8.2 13.5 1100 W
RG 8X 78 2.5 3.7 5.4 8 13 200 W
RG 8U 66 1.5 2.2 3.2 4.7 8.2 350 W
RG 213 66 1.5 2.1 3.2 4.6 8.2 350 W
RG 9U 66 1.4 1.9 3.0 4.1 8 350 W
RG 214 66 1.3 1.9 3.0 4.1 8 350 W
RG 8 FOAM 78 1.2 1.8 2.7 4.2 7.1 250 W
9913 84 0.9 1.3 1.8 2.7 4.5 400 W
FLEXI 4XL 84 0.9 1.3 1.8 2.7 4.5 350 W
1/2" LD HARD 84 0.5 0.68 0.92 1.5 2.3 1200 W
7/8" LD HARD 84 0.16 0.24 0.66 0.8 1.4 1500 W

R. Shewell, N2HJD

February 1998


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