Oops. My bad. James, not Bob.
73, Roger W7TZ CN83ia
On Thu, Oct 13, 2016 at 3:12 PM, Roger [email protected] wrote:
Bob, you're going to get a wide variety of answers to your question and for good reason. All insulation is not created equal and therefore will have varying effects on your project. I'm not aware of a simple formula either but could possibly assist in your efforts. It sounds like you want to use 10awg Romex. In this case, I'd strip the insulation from the copper, secure one end of the copper in a vice or similar device, put the far end in a variable speed drill and gently twist the copper wire to create stiffer material. What yagi design do you have in mind? How many elements? What type of feed? How high do you intend to mount the antenna? These things all need to be taken into consideration for efficiency.
73, Roger W7TZ CN83ia
On Thu, Oct 13, 2016 at 2:41 PM, Bob [email protected] wrote:
The best I can do for you comes from the documentation for antenna modeling software which does cover the impact of the element diameter. The impact on the driven reflector is almost zero. The impact on the directors is not quite zero.
Doubling the diameter of the element, example going from 12.5mm to 25mm (1/2" to 1") will cause the driven element to SHORTEN by 5mm (that's about 0.2 inches). In other words, you can pretty much forget it. The impact on the directors is larger, SHORTENING it about 25mm, or an inch. But even so, these dimensional changes are FAR less significant that the changes due to height, ground characteristics, and what else is near the antenna. In other words you can forget about factoring it in.
Same thing is pretty much true for insulated vs. non-insulated wire -- you can pretty much forget about it.
Good luck!
73, Bob, WB4SON
On Thu, Oct 13, 2016 at 5:15 PM, James Hickox [email protected] wrote:
Hello All, I am wondering if there is any "simple" conversion factor to use to modify the length of an antenna element from insulated #10 AWG copper wire to anther gage of wire or to aluminum or copper tubing. I don't wish to learn any modeling software at this time I need the information so I can use materials I have on hand to build yagi antennas for 2 meters and 70 centimeters. Thanks and 73,James, AA5AO _______________________________________________ Sent via [email protected]. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership.
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