Topband: Noise and reception

[k3ky@erols.com]

Hi, Tom-
Frankly, I have zero emotional investment in whether the loop
receives any horizontally polarized signal or not. The fact
remains that I am seeing real, usable improvement in S/N over
my 80 and 160m tx verticals. I am open to explanations of what
other mechanism makes this antenna work- just so long as you
are not trying to convince me that I should ignore the evidence
of my own ears.  :o)   BTW my version of K6STI's loop seems
to hear, on average, about as good as my Flag and K9AY and
shorty 225ft Beverage. It hears the best of the bunch to my
south, as the other 3 antennas beam NE or W. It seems to have
some unusual characteristics, being the only supposedly non-
directional antenna of the bunch. These are difficult to describe
or quantify, but my ears clearly tell me that there is something
useful in S/N improvement taking place. How can this be if
the antenna is truly omni-directional *and* is a cloud warmer
*and* does respond to vertically polarized energy (noise) after
all? Something does not compute here. I am not yet ready to
discount K6STI's explanation of how the antenna operates, at
least not entirely. OK, so this antenna in the real world
technically should not work- but mine does. Why? And why
did the prototype W6KUT antenna work? Why is the performance
repeatable at all, even just twice?  If I were to fully follow
and surrender to your line of reasoning, I would never have
built the antenna in the first place, and it should not have
worked.
BTW, for further discussions, if any, I did not take extreme pains
to make the antenna either precisely square or precisely level.
I did a fairly good job with careful measurements and used a
spirit level briefly, but I doubt it is exceptionally symetrical or
level. I certainly did not achieve quarter inch accuracy, as an
earlier post alludes to. I did carefully follow the designers
hints regarding the construction of the open wire line and the
tuning box connections. What got me going was when a user
advised that he had build a substantially modified version of
the loop and was not impressed. I would agree with you that
the construction would be tricky, and therefore thought it unfair
that the antenna would be slammed on that basis. I was not even
responding to your posts BTW, which seem entirely reasonable,
other than perhaps your sarcasm.
Tom, have you ever actually built a K6STI loop? You say that
the vertical loops 'want to work' but this horizontal loop does
not. I would have to disagree with that assertion. Aside from
theory, do you have any experience or factual basis for
believing that? I must say that I have detected, at times, a note
of impatience and even sarcasm in your posts about various
'non-workable' designs. This one obviously made your list.
I am sure the antenna is no exception at all, and conforms to
the laws of physics just like any other antenna, albeit in a
complex manner, as is always true in the real, imperfect world.
Despite the power and logic of your arguments, you have not
yet persuaded me to take down the antenna. My ears advise
otherwise. The antenna has been a valuable asset to me.
Is there a more likely explanation for how the antenna actually
works that differs considerably from K6STI's assumptions?
I think we would all benefit from hearing it- I know I would.
So far for me, the gist of your arguments is that the antenna
should not work- but it does!
Thanks for all your great posts over the years, Tom. I have 
learned a lot. Your key clicks mods have been especially a
great service to all!  73, David K3KY


On 17 Feb 2002 at 2:01, Tom Rauch wrote:

> > I believe the K6STI loop and even
> > the Flag/Pennant family are getting unfairly slammed in the
> > informal ham 'press' such as the Topband group. 
> 
> I don't think so Dave. 
> 
> I think it reasonable to point out as antennas are made smaller and
> smaller, they generally become more and more critical to build.
> 
> It is also reasonable to point out that the K6STI loop is very
> critical to construct, because the nature of the antenna makes it very
> sensitive to balance. It is so insensitive, it might not be possible
> to balance it without special "tricks" or effort.
> 
> As a matter of fact, the very thing that makes the K6STI antenna NOT
> want to work is part of what makes Beverage, EWE, Flag, and Pennant
> antennas "want to work"!!! 
> 
> For those of us with small well-balanced loop antennas, I'd like to
> suggest a little experiment. 
> 
> Take the small loop antenna and lay it over flat near the earth's
> surface, and watch the general levels of all signals. What you will
> see is a properly balanced loop just about goes dead, or at least has
> a very major reduction in sensitivity, when laid flat a few feet above
> earth.
> 
> The reason for this is simple. The earth effectively "short  circuits"
> the horizontally polarized electric field. The loop, Beverage,
> Pennant,  Flag, and even the K6STI antenna don't like to respond to
> horizontally polarized signals because of the earth. There just isn't
> much horizontally polarized signal there, if the earth has any
> reasonable conductivity. What horizontal component there is mainly
> comes from very high wave angles!
> 
> On the other hand, vertically polarized signals are re-enforced by the
> earth. Antennas near earth "want" to hear vertical signals, because
> the earth tends to re-enforce vertically polarized signals and cancel
> horizontally polarized signals.
> 
> Actually, this is also the very reason ground wave propagation 
> must be vertically polarized, and why the noise that propagates 
> along the earth for a distance is all vertically polarized.
> 
> We might wish otherwise, but we can't have mother earth treat one
> antenna in some special way! 
> 
> We aren't being unfair or pessimistic in telling the truth.
> 73, Tom W8JI
> W8JI@contesting.com