Jim wrote:
>>> An easy way to get close to the actual length is to put a connector on one
>>> end, leave the other end open, and measure the impedance with an antenna
>>> analyzer. At every frequency where it's some odd multiple of quarter waves
>>> long, it will look like a short. So sweep it with whatever analyzer you
>>> own, write down those frequencies, and do the arithmetic.
There's an expanded explanation of this technique, with illustrations, on one
of the Zplots pages. See section "Line Length via Quarter or Half-Wave Points"
here:
http://ac6la.com/zpapndx1.html
So if your analyzer can produce a Zplots-compatible file, and you have MS
Excel, you can let Zplots (http://ac6la.com/zplots1.html) do the math. An
alternative not requiring files or Excel is to use the "Conversions" button
from the TLDetails (http://ac6la.com/tldetails1.html) program. Either way, be
sure to enter the frequency *difference* and not an absolute frequency.
Both Zplots and TLDetails are free.
Dan, AC6LA
http://ac6la.com
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