J-pole dimensions using 450-ohm window line

Fred Dittrich


The subject of j-poles constructed out of window line came up at lunch. From my notes of 4/1/16 here are the dimensions to center on 146 MHz as measured from the bottom and verified by my AA-600:

Where: Unmolested window line is at the bottom and one conductor only continues above that section.

Short the "bottom" of the j-pole, and measure up from there:
30 mm from bottom - this is the 50 ohm coax attachment point
453 mm from bottom - this is where you remove one of the conductors all the way to to the top
1402 mm from the bottom - this is the top of the j-pole



Fred AE0FD

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