To: <topband@contesting.com>
>Date: Mon, 23 Mar 1998 22:51:00 -0500
>From: jbmitch@vt.edu (John Mitchell)
>
>> We (other than you) have been discussing ground
>>mounted 1/4 wave tall vertical antennas either with elevated or
>>with ground mounted radial systems of varying densities.
>
>There are multiple dimensions to this thread; if's disappointing
>that you take ownership, via the royal "we", and exclude the
>other sides being discussed. No matter, there IS a very lively
>discussion on elevated feed point versus ground mounted
>vertical. There's no point in arguing over this.
I wasn't aware that I was arguing with anyone. And, just for the
record, that 'we' wasn't intended to be royal in nature or to
take ownership of anything other than the original intent of my
words which you quoted. It was more like a "choral" we. I was
quite careful to define the narrow range of what _I_ was
discussing when I began my posts on this subject here.
Perhaps it would have been useful for your post to include a more
explicit definition of exactly what your 2 radial wire ground
system is better than. If you had, I may not have made the
faulty assumption and probably wouldn't have responded.
>>Or better yet, run it at 12 feet and then do the same thing
>>with it at 32 feet Let me know if higher isn't better.
>
>Of course it is, but the contention some of us are discussing is
>that using resonant, elevated radials at a modest height may be
>better than ground mounting the system.
Yes, and this point has been conceeded a number of times. But
you must be quite careful to define the exact circumstances of
the comparison or it may very well NOT be true.
For example, it is NOT true over perfect ground as long as the
height of the top of the antenna must remain the same (fixed
existing support or tower radiator). And "better" should be
defined as well. Better in therms of effort to improvement
ratio? Better in terms of the percentage of the power fed to the
system which radiates versus what is lost? Better in terms of a
gain figure at a single elevation angle due to a directivity
change?
Again, nobody is saying that given any particular set of
circumstances which prohibit the full density screen, it is a BAD
idea to use however many elevated radials that can be supported.
Merely that if you do that, and the elevation height is not
fairly large, and the number of possible radials is not large,
and the ground in the vicinity is lossy, there will be some
remaining loss in the system which (if the circumstances
permitted) _could_ be reduced with a full density screen.
>Maybe we should name this thread something different to avoid
>confusion?
Possibly a good idea.
73, Eric N7CL
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