Hi I have an idea for an antenna my idea is to use a 3 meter 4 inch pic pipe as an antenna I would wind numder 14 insulated wire around it kind of like a CB whip can anyone out there till how much wire to wend around it.
First, start by knowing the turns per inch for the wire. This depends on the type of insulation but there are tables available for this.
From this the number of turns (N) will be the length (L) in inches multiplied by the turns per inch (TPI). Three meters is 118 inches so if, for example, you have 10 turns per inch then the number of turns will be LxTPI = 118x10 = 1180 turns.
The length of wire for each turn is approximately pi x D (the diameter) or 3.14 x 4" = 12.56 inches. Multiply this by the number of turns to get the total length, so for this example the length of wire is 1180 turns x 12.56 inches/turn = 14,820 inches which is 1235 feet.
You need the actual turns per inch for the wire you want to use and repeat this calculation. Also, this assumes that the wire is tight wound with no spacing between turns and this is probably not what you should do. You should read up on helical antennas for more information. You might find this helpful: http://www.hamuniverse.com/k6mm160metervertical.html
Neil
From documented research, field experience, and MoM software modeling including Part 15 AM/Ham Radio/Commercial/Broadcast antenna systems over many years, the radiation pattern and gain for ANY number of turns of wire comprising a normal-mode helix "coil" antenna wound along a coil form of a given OD and length are pretty much identical to that of a vertical monopole using a linear conductor of that same end-end length, OD, and operating frequency (proof on request).
IOW, "X" turns and "Y" feet of wire used to wind such a helical antenna would perform about the same as a tubular conductor of that same OD and length, other things equal.
I will be using #14 wire from home depot