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Sal M. Onella wrote:
More musing: Does the entire "J" have to be upright? Can't I put an elbow where the quarter-wave and half-wave sections meet, so the radiating element is vertical, but the quarter-wave section is horizontal? (In the case of a tower side-mount, this would position the radiating section a nice distance from the tower. Inverted OK.) Sal, I think that the position of the J affects its polarization. Around 1995, I did some informal experiments with an MFJ 300 ohm twinlead J-Pole and 2m SSB. I used a Yaesu FT-290RII with 2 watts output. At 2m, polarization is important and I found that by laying the J-Pole horizontaly, I was able to extend the range of my signals, even if I layed the antenna on a wood picnic table. I did not experiment with the antenna in a mixed orientation as you describe above. Another posibility is to place a 300 ohm J-Pole antenna inside a rigid PVC pipe. If the pipe is long enough, the base can be clamped without affecting the antenna. This does move the feed line from being extended horizontaly at the feed point to being extended verticaly downward, but this did not seem to effect the antenna, and the MFJ unit I have is designed that way. The 450 ohm ladder line units I have made are built with a horizontal feed, but that's more lazyness than anything else. 73, Geoff. -- Geoffrey S. Mendelson, Jerusalem, Israel N3OWJ/4X1GM |
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