Allen Crites correctly pointed out that I had fat-fingered the wavelength of
the factory cable I had in the original version of the text - I fixed it.
Also, I had previously estimated the physical length of the type N elbows to
be about 1.5 inches, or 0.12 wavelength. For the heck of it, I measured the
actual phase change on the network analyzer when an elbow was added and
found it to be 53 degrees at 915 MHz (about 0.15 wavelength), so I changed
that in the article too. Both the cubic-style and miter-style elbows
measured about the same (53-54 degrees). Since two elbows produced the
worst performance degradation, and two elbows would be a little more than a
quarter wave (0.15 x 2 = 0.30), theoertically there is a length slightly
less than the equivalent of two elbows that would produce even worse
results, assuming of course that the factory cable is truly of ideal length.
Revised version posted at www.broadsci.com/900.pdf
--- Jeff
