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calculating antenna size or transmitter power based on field strength?

tfcwings said:
Let's assume I know the field strength I'm looking to get at a particular distance. I also know one of either the antenna length, or the transmitter power, but not both. Assume the antenna is directly connected to the transmitter, to eliminate any transmission line loss that may occur... although there may be 50 feet or more of audio cable connecting to the transmitter's audio input.
If I know the transmitter power and field strength at a specified distance, how would I calculate the antenna size required (while allowing for a calculation to basically tell me something's wrong when I attempt to do something that's physically impossible)? Or, if I know the antenna size and field strength @ the specified distance, how would I calculate the transmitter power? Basically what would be the formula for calculating those? I'm assuming antenna size would be calculated in fractions of a wavelength, and I could convert it to feet & inches or meters from there.
Click to expand...


And ... going back to the original post ... I don't think it is unreasonable to come up with some ballpark suggestions for tfcwings to at least find a reasonable starting point. If there are some things that make the calculations difficult or impossible, like a held transmitter with a short antenna, then that should be addressed and a more predictable configuration could be suggested (this is what he is asking). Instead, we have seen a lot of obscure theoretical discussion toward trying to prove that what he is asking is impossible to calculate. A sound engineering approach would be to make some assumptions that enable a calculated solution, and then modify the assumptions until an optimum overall solution is found. I don’t think tfcwings is any better off now than when he first posted on May 20. He like most others is probably more confused now than when he first posted his reasonably thought out question.

Why not start do a RESET and start over with the goal of helping him find a solution.
 
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