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In article ,
Yuri Blanarovich wrote: I think there is a major misconception that verticals are more sensitive to noise because the noise is "vertically polarized". Man made, appliance or otherwise produced noise is "all kinds" polarized. It is the antenna's location and radiation pattern that determines the amount of noise or S/N pick up. Well... yes and no (I think). As I understand it, ground-wave / surface-wave propagation occurs for vertically-polarized signals (or signal components), but not for horizontally-polarized signals (or components). Even if manmade noise is polarized in all planes with equal (or randomly distributed) polarization senses, only the vertically polarized portion of it will travel via groundwave propagation. So, I suspect that the noise-proneness of vertical HF antennas compared to horizontal dipoles, probably results from a "double whammy". The horizontal antennas aren't exposed to anywhere near as much energy propagating via groundwave (because horizontally-polarized noise doesn't travel well in that mode), and they aren't as sensitive to it because they often have fairly high radiation angles with a substantial null towards the horizon. The vertical antennas are hit with more noise energy, and due to their low radiation angle they're pretty good at picking it up. -- Dave Platt AE6EO Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior I do _not_ wish to receive unsolicited commercial email, and I will boycott any company which has the gall to send me such ads! |