[Lowfer] antenna current & progress

[Ed Phillips]

"Too soon to expect an improvement w/ two radials. From what I
understand a min. of, say, 25 radials before an effect on performance
and "I." I've mentioned before the Sevick series of articles (1970s QST)
on ground radials for HF verticals which concluded that 60 gave
significant improvement and that since the greatest density of return
current near the center, that is where the concentration should occur.
By that he explained that starting from the "broadcast ind. std." of 120
quarter wave radials, if that is not possible then what and where can
the compromise occur. His conclusion was on length.  His empirical tests
showed that one could reduce the radial length in relation to the
reduction in number. Another way to say this is if the number is
compromised then there is no merit to fully extend the others, ie,
better cover the near area first before extending to the far radius."

	I don't think that statement about the improvement with number of
radials is correct.  My copy of Laporte's "Radio Antenna Engineering" is
at work so can't refer to it, but in one of his figures or tables he
shows the effect of adding radials.  According to that, four is a very
good start and it doesn't take long to reach the point of diminishing
returns.  For BC work where the coverage area is an important term in
figuring advertising revenue an improvement of a dB in radiated signal
might well be worth the cost of the extra radials.  I'll try to see if I
can scan those pages and make them available to anyone who's interested.

	I think his information is good.  At least my antenna design friends
consider it the last word for BC antenna design.

Ed