Verticals have always held a fascination for me.
But I wonder to what degree my fascination is overly influenced by
misleading articles and unscrupulous advertising.
There is a ham...maybe about 3 miles from me who resides in farmland
area which is wide open fields, open to the horizon in most directions.
Unlike my property which is a few feet of soil surface over very deep
shale rock, at a 30 degree incline, and in the woods.
He is on a tiny lot, and his only antenna for years has been a ground
mounted vertical.
But he is convinced that vertical is the next best thing to a yagi up 75
feet for DX.
Yesterday I read an online article about the 1/4w raised vertical with 4
radials which is ubiquitous in classic antenna books.
He was talking about current flow within radials and asserted that with
only 4 radials the current flow required of those radials
would impose a high voltage potential on feedline shielding which would
result in a high degree of common mode noise ingress fed back to the
receiver.
And that hams un-aware of that noise source would assume the vertical is
simply a poor antenna.
And even some forms of common mode choking would not be effective given
proximity to radial currents.
He concludes that the classic presentation of 4 raised radials is
misleading and that a minimum of 25 radials would significantly reduce
common mode ingress.
Common mode noise is widely discussed among most antenna minded hams.
And it seems radials are the most painful aspect of verticals, and
commonly understood in terms of maximizing the transmitted signal
But I don't remember hearing much about minimal radials affect on the
receiving characteristics.
For about 2 years, I had a 43 foot vertical with its base up 30 feet, 15
radials and a kw isolation choke.
When I could consistently hear JA and VK stations on the doublet and not
on the vertical it eventually came down.
The vertical will just have to remain a fascination for me. :-]
--
Bw_dw@fastmail.net
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