LONG doesn't begin to describe that one.
Yes, .81 is a good place to begin.
Cut it long, short the end and measure the impedance at the other end of
the WHOLE LINE (Hardline plus RG-11). You want the resistance to go to
ZERO at 14 MHz (MFJ antenna analyzer or equivalent).
With only 150 ft, you will save less than 1 dB over RG-213. RG-213 will
have about 1.4 dB MAX loss at 14 MHz. Half inch hardline will be about
0.5 dB. (3/4 inch hardline will be about 0.3 dB.) RG-11 has slightly
higher loss than RG-213. You may want to look into some of the lower
loss 50 ohm lines that do NOT have air space in the dieclectric.
My rule of thumb is that hardline becomes viable with lines of 200ft of
de Tom N4KG
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