Jim,
Check out the work done by W8JI/ON4UN/N7CL as to some
actual REAL WORLD measurements ... also make sure to
understand the differences between 1/4w and 1/2w verticals
as to the role of radials, ground planes, etc.
The models have NOT proved to be totally accurate is the
bottom line of this. ON4UN's Low Band DX book would be
another source of some good background reading.
Tom, W8JI ... you still have those measurements you made?
73 Billy AA4NU
----- Original Message -----
From: "Jim Shaw" <Jim@shawresources.com>
> Further, according to some credible articles, elevating a vertical, or at
> least its radials, even just a little bit, usually pays dividends. So much
> so that maybe 4 or, at most 8, radials per band would provide as good or
> better ground than 45 or more buried radials. The last reference listed
> below is so adamant about this that it specifically states that one of the
> "lessons learned" from the expedition was "Under most any circumstance,
> radials should be elevated".
>
> I know there is some controversy about the value of elevating a verticals
> (or at least the radials), but I would appreciate learning more. Please
> fire away. BTW, here are the references so you can check them out
yourself
> and see if I am misreading them.
>
> 1-"Elevated Vertical Antenna Systems: Is your vertical system performance
up
> to snuff? If not, maybe it needs a lift - in elevation above ground that
> is!". (ARRL "Vertical Antenna Classics, KB8I, pg 108).
>
> 2-"Elevated Vertical Antennas for the Low Bands: Varying the Height and
> Number of Radials" by KB8I, The ARRL Antenna Compendium - Vol 5.
>
> 3-"Vertical Dipoles and Ground Planes: What Antenna Modeling Reports" by
> W4RNL available online at http://www.cebik.com/vdgp.html
>
> 4-"Verticals for Contest Expeditions: Learnings from the 6Y4A CQ WW CW
> Contest" By Kenny Silverman, K2KW and Tom Schiller, N6BT.
> http://www.k2kw.com/verticals/learning.html
|