On 13 Nov, 15:23, Roy Lewallen wrote:
I'm glad my harping on this topic (mostly via Chapter 8 in the _ARRL
Antenna Book_) is having an effect, and that some folks are catching on.

The receiving antenna trick is to begin with elements that are either
very short or very lossy or both. This reduces the effect of mutual
coupling to a negligible value, so all elements will have the same
source impedance. Then the transmission lines are all terminated in
their characteristic impedances at the receiver end. This is the
condition under which the delay in the lines equals their electrical
lengths. Under those conditions, the scheme works nicely.

Roy Lewallen, W7EL



Denny wrote:
In doing some study of active receiving antennas I see in a couple of
white papers on the subject that the author determined he needed a
specific phase shift between one or more of the elements and the
combiner, such as 110 degrees, so he proceeded to cut a specific
length of coax determined by it's velocity factor X the desired
fraction of a wave...
This is one of those things that you always accept at face value in a
published work, but this time my doubting side kicked in... We know
that simply inserting a nominal electrical length of coax - such as 90
deg or 180 deg - into phased transmit arrays does not work as planned
most of the time due to mutual coupling... I have read the
contributions of Roy and Al Christman, et. al. on this not
intimating that I understand it...
Anyway, in shortened, loaded, active amplifier, receiving arrays can
one simply insert a nominal number of electrical degrees of phasing
line as the mathematical model calls for, or is their more to it...
Hoping that Roy, AL, or Walt, or others will chime in here...

denny / k8do- Hide quoted text -

- Show quoted text -

By Golly. Well done. You should get a gold medal from your peers
namely George W Bush.
You and you alone was the first to point this out to the scientific
community.
You take credit for harping on it in a published book knowing if it is
in
a book it then qualifies as being right.
What ever did the radio community do in those
case before you were born or came along? You should undoubtedly get a
medal for harping in leau of saying "I don't understand" or you
can't
use mechanical laws when the subject is electricity" plus some of
those things you have stated that Cecil could remind you of.
Yes, the credit is yours and you get the gold medal and a fireside
chat with your equal and possibly a mentor George WWWWWWWW BUSH.
YEA....