Hi Roy,

"Roy Lewallen" wrote in message
treetonline...
There are two errors in your analysis. The first is that you've neglected
mutual coupling between the elements.

Yes, I assumed it was negligible. When we analyzed arrays in class some years
ago, the starting point was always, "assume each antenna has the pattern of a
single dipole in isolation, is matched to the transmission lines, with input
current 1A @ angle whatever." We did analyze the patterns for a couple of
local Oregon TV & radio stations, BTW, including whichever radio? station it
is up in Portland (very roughly) near you off of I-205 as you drive past
Oregon City.

But that happens only in special cases and not by any means all cases.

The phased arrays I had in mind were those that were usually separated by a
"significant" fraction of a wavelength, e.g., lambda/8 or more. That's
probably not far enough apart to neglect coupling?

Your correct value of 1.414 mV/m is correct, but it represents a 3, not 6,
dB gain relative to a single element (which produced 1 mV/m).

6dB vs. 3dB is a rather embarassing outright brain fart on my part. :-) (The
usual case of confusing "twice the power = 3dB" with "twice the voltage =
6dB").

For a much more detailed explanation of these phenomena, I recommend reading
the treatment of phased arrays in Chapter 8 of the _ARRL Antenna Book_. I'm
admittedly a bit partial to this particular treatment, since I wrote it.

Thanks Roy, I'll take a look!

---Joel