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![]() "Spike" wrote in message ... Thanks for the comments, Jeff. Perhaps I'm not being clear enough. Look at the issue this way.... While it's clear that the totality of the e/m emissions from from the antenna depend on factors such as length, height, and ground, (and I originally assumed a particular set-up in the OP) there are three distinct methods by which such a transmission can be received: the sky wave path to a distant receiver, a space wave to a line-of-sight receiver (that could easily be outside the surface wave range) and the surface wave to a receiver tucked into the far side of a hill with no sky wave or space wave path. It can be expected that increasing the transmit power will increase the received signal at all three locations, but the question I'd like to see answered is: what proportion of the power supplied to the antenna goes to each of these three phenomena, which all arise every time the transmitter is keyed. They might all be connected by the conditions you mention, I'm not suggesting they aren't, but for the set-up I originally described, what are the proportions of the power supplied to the antenna that contribute to each? Or, to put it in yet another way...There might only be one 'wave' launched from the set-up, that propagates in three different 'modes' (for the want of a better word); so what controls the relative power/energy with which each 'mode' is propagated? You have to get it in your head there is not 3 differant waves launched from the antenna. There is only one wave. As it leaves the antenna, whatever the wave hits determins if it is ground, sky or whatever. The patern of the antenna determins how much goes where. With some antennas the patern is such much of it goes out to the horizon and not much up in the air. Others radiate much to the vertical and not much toward the horizon. Think of it as throwing a rock into the middle a small pond. If there is noting in the pond, the wave will go out toward the edges equally. If that same rockis thrown in near the edge of the pond, some of the ripples will n hit th eedge of the pond near the rock first while it will take some time for the ripples to hit the other side. You have the same origional wave, but its propogation is modified as to where it is at . You do not have seperate waves leaving the rock. |
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