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Roy Lewallen · November 13th 07, 11:16 PM posted to rec.radio.amateur.antenna

wrote:
On Nov 13, 8:05 am, (Rick) wrote:
On Mon, 12 Nov 2007 18:54:14 -0800, Roy Lewallen wrote:
Try deleting the parasitic element and see what the gain of just the
driven element is.
Ok, I did. The gain at 7 MHz went from 11.2 to 7.22 dbi, at 30 degrees
elevation angle.

Rick K2XT

That seems more reasonable... Heck, a NBS yagi with 3 elements
only gives about 9.4 dbi plus or minus.
MK

That's the gain of an NBS Yagi in free space. It's more like 13 or so
over ground, depending on height and ground characteristics. Comparing
the gain of one antenna over ground to another (for example a dipole) in
free space is a trick often used by antenna manufacturers to fool naive
people. Both must be in the same environment for a comparison to be
meaningful.

Roy Lewallen, W7EL