My Ladderline Jpole Dimensions

Darryl J Kelly

Thanks for interest. Let me tell you about my best one. It is made
with 450 ohm ladder line, #18 solid wire I think. The ladder line
section is 19 7/8" long, shorted at the bottom, and tapped for the
coax at 2 1/4" from the bottom. Attached to the center coax wire side
is 33 1/4" of #18 stranded insulated wire, total length 53 1/8"
including the matching section, connected to about 6' of 50 ohm RG-58A
coax, length optional. It measures SWR 1.5 at 144.00 and 148.00 Mhz
with 1.0 at 146.50, and 2.0 from 440.00 to 450.00 Mhz. I really don't
know about tuning these things, I think the position of the coax tap
affects SWR, but the rest is trial and error. I can make another one
to the same specifications and it will not test out the same, close
but not always the same. I never could get the 300 ohm jpoles to test
for anything right, too hard. Hope this is of interest.
Darryl, KK5IB

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