[TowerTalk] (no subject)

[Franklyn Brooker]

Mighty long discourse on a matter which has no title.


Frank 9Y4VU


-----Original Message-----
From: K7GCO@aol.com <K7GCO@aol.com>
To: towertalk@contesting.com <towertalk@contesting.com>
Date: Thursday, September 14, 2000 12:54 PM
Subject: [TowerTalk] (no subject)


>
> In a message dated 9/13/00 4:34:23 PM Pacific Daylight Time,
>w8ji@contesting.com writes:<<
> From:              K7GCO@aol.com
> Date sent:         Wed, 13 Sep 2000 18:17:16 EDT
>
> >  Tom:  I "very clearly" stated that I ran a series of tests in Eznec
with
>a 7
> > element yagi.  You have not.  It was very very clear that any guy wires
> > (even tips of 1/4 wave grounded guy wires) with the tips 1/2 WL from the
> > top of the tower were "virtually immune" to the beams field below the
> > tower.  It was on a level of what was on a tower with a horizontally
> > polarized beam with no RF Spill Over on the feedline.  The computer
> > "RF Source" is right at the feedpoint so there is no feedline shield to
> > spill over on to.
>
> How many different guy lengths did you model?
> *******4 Grounded Resonant 1/4& 5/8 WL and ungrounded 1/2 WL guys that
ended
>up 1/2 WL from the tower with a 3&7 element 10M beam as they had the best
>chance of absorbing RF from a beam at some different orientations.  I just
>don't have the time to do it for 4 of them over 90 degrees at 1 degree
steps
>in Eznec.  I did it with the 2M beams real fast.  It should scale on the
>lower bands.  I presume that was a good test.  If it's not do it yourself.
>
> How many different antennas?
>****Count them.
>
> Did you vary the length of the guy lines?
> ****Read the 1st sentence.
>
> What angle were they at?
>  *******45 degrees
> > Now you state that "its possibly true for small beams (perhaps 2M)
spaced
> > 'well above' the guys it is most likely correct".
>
> No, I didn't say that. It is a better idea to cut and repost what I say,
> instead of quoting what you "think" I might have said.
> *******You do it all the time to me and others so I thought I would see if
I
>could slip the (2 meter) possibility past you--for clarity.  I was very
>specific.  Out of curiosity what band were you possibly suggesting?  Since
>you said it's possibly true for small beam"--what did you have in mind for
a
>distance greater than 1/2 WL?
>
> > stated "have the guy wire tips "1/2 Wave Length from the tower
connection
> > and beam."  That doesn't mean "Well Above."  It's not a "Relative
>    Measurement."  It's a  "Precise and Exact Measurement".  Example"  It's
>    about 39" at 2M (small beam) and 35' at 20M (large beam).
>
> I'm not sure what you are saying. (?)
> *******39" on 2M and 35' on 20M are about 1/2 WL (Wavelength).  Here is
how
>you calculate it.  Example 492/14.057 MHz=35'.  You try this one and tell
me
>how far I was off.  492/146=???  I thought you would catch it.  What is it
>about a 1/2 wave you don't understand?
>
> Are you saying that with guys at any angle and any attachment
> point and length, the guys only need to be 1/2 wl from the antenna
> (and tower) to not affect pattern?
>
>*****Good point Tom.  I didn't try it closer than 45 degrees.  It should be
>obvious
>that the closer it gets to the tower the more it assumes the structure of
the
>tower--and the least possible affect and absorbtion.  As the guy wires with
>the tips 1/2 WL from the tower are increased in angle above 45 degrees they
>get out from the field underneath and are 1/4 WL from the tips of a dipole
>and less from the elements of a yagi.  There are angles where any coupling
>would be zilch.  Since no one but maybe you would run a guy wire horizontal
>or worry about it--you scale it in Eznec.
>
> Have you got the "Exact Distance
> > Picture"?  It's in "Wavelength."  It's NOT a "General Rule" as you
> > suggest.  It's an "EXACT K7GCO RULE" I derived from High Level Computer
> > Interpretation.
>
> Other people may have higher reading skill values than I do. I have
> a difficult time understanding how that rule is "exact". It seems
> vague to me.
> ******** A half wave is a 1/2 wave, is 1/2 wave, is a 1/2 wave.  Review
the
>math above.
>
> How many combinations dod you model?
>*******Covered above. If not enough do some different lenghts yourself.
>
> > If you understood Basic Beam Tuning 101 you would have full knowledge of
> > the fact that in order for each director change (and the Rr--that's
> > Radiation resistance) to increase gain at less than 1dB (and a bit less
> > progressively for each one), they have to be:
> >  1.) In the same plane
> >  2.) Of the same polarization
> >  3.) The right spacing
> >  4.) The right length
> >  5.) All joints have a "Reasonable Conductivity and a Longevity Factor".
>
> Filling in or moving nulls is as much or more of a problem than
> increasing gain. It takes only the smallest amount of re-radiation to
> destroy the null of an antenna.
>
>*******That's true but if a null is over a guy--how much RF is going that
way
>at maximum and how much is coming directly back of the right orientations
to
>have any affect at all?  It is true that resonant objects (with enough
>orientation clout) can affect a pattern some not directly in line.  The
over
>all pattern is the summation of all factors.  A director can have a big
>affect on the F/B.  For maximum gain change less than 1 dB for each drector
>It takes the beams full frontal gain lobe in line into these directors.
>Nulls don't have much clout to create a pattern change.  It tends to reject
>what little that comes back also.
>
> A conductor 100 feet away can easily change the pattern of a yagi,
> as does the earth at that distance and further, on 20 meters.
>*****Tom a director or object to affect gain has to be a certain spacing
and
>all the other requirements.  I stated that objects in front of a beam
further
>out will affect the ground reflection pattern but not the free space
pattern
>or the DE Z (Driven Element Impedance).  Experiment with the 2M beams I
told
>you to and you will ask better questions.
>
> Respectfully, I think your "exact rule" is too poorly defined to be
> considered an exact rule.
> ******Frankly I couldn't care less.
>
> > If it's not and frequently it's not with yagi's after a time period
without
> > the right element goop.  It lowers the Q which is like any other
critical
> > tuning factor in gain and F/B.  When the elements eventually becomes
> > capacitive reactive at the joints, it literally neutralizes the other 4
> > even if properly adjusted.
>
> How does the "capacitor" formed in the oxide withstand the voltage
> from the element without breaking down?
> ******You ask it not me.  I pulled some elements that had been together
for
>50 years and the Aluminum Oxide (Alumitoid Yagititus--Terminal Case) had
>increased the diameter on the inside tubing .015".  It was a very very
tight
>fit requiring a special "jack hammer technique" to get the joints apart and
I
>saved all the aluminum now worth about $1000 if I had to purchase it.  It
>tested capacitive before disassembly and the Aluminum Oxide coating was
very
>clean.  The SWR was high and never flickered.  I could only get about 20W
>into it due to the high SWR so that lowered the voltage potential
>substantially at each joint.  There was very little F/B where it averaged
30
>dB+ around the back with clean joints 50 years ago and after cleaning.
Even
>if the capacitor arced through that's still a bad connection.
>
> > of each and every element--100% of the time.  Quads have the advantage
of
> > having "one permanently soldered joint and never detunes" if
> > soldered--some aren't.
>
> I've never seen an element joint problem with my yogis. I think that
> problem is a greatly exaggerated problem.
>******You probably didn't recognize it as the affects are gradual and slow.
>F/B is usually the first indicator and then a SWR change.  These joints
>didn't have any goop on them and it's a worst case.  I made believers out
of
>some DXers and they clean before every contest or antenna tests as I do.
To
>eliminate that I came up with the Flea market solder that works great and
now
>I have "ZERO MAINTENANCE ELEMENTS" going on 7 years.  The biggest
>"exaggerated problem" really is getting you to do some hard cold hard
>research you can understand and if possible review their data before you
>literally call them a liar.
>
> > Guy wires 1/2 WL or more slopping away even if resonant do not under any
> > circumstances full fill all 5 critical tuning factor requirements.
>
> How do you know? They can be almost any angle, and length. How
> do you know they are non-resonant?
>******Review the "5 orientation statements".  Since the lengths are known
we
>are back to basic math.  492/ft = MHz (1/2 wave).  I used 4 radials of 3
>resonant lengths in my tests.
>
> > recommend at least 1 insulator at the tower if metal guys are used full
> > length.  Put another one in at say 10' if it makes you feel better.  As
> > the gain of a beam increases, the vertical pattern sharpens--that means
> > less pattern BELOW.
>
> I just modeled a 40 meter yagi using you guidelines above, and
> when the guylines are resonant the front to rear null ratio in the
> model goes from almost 40 dB down to ten dB. You seem to imply
> that can't happen, if I understood you correctly.
> ****That was another test to see if I could get you to do some research in
>the Computer.  However I would like to see your data.
>
> The beams pattern below becomes progressively immure
> > to any specific non resonant object around it except in the front and
even
> > then it still has to full fill ALL 5 requirements of above.  For example
a
> > 2 element beam may have a 50 degree -3 dB point above and below where a
5
> > or so element may have around 30 degrees or less.
>
> That is a far field pattern, not a near field pattern. You certainly
> have the right to use a far-field pattern to predict there won't be a
> problem, but you should remember the answer will likely be wrong.
>******Says you.  I'll repeat it again.  Play with the 2M beams and prove it
>to your self as I did.
>
>  > correctly adjusted, each director adds less and less gain and has less
> > change on the Rr.  Take a 3 element and then a 11 element 2M yagi and
move
> > a director around it and watch the SWR and S meter.  A 2nd reflector for
> > example of the right length does virtually nothing in the back--there is
> > the 3rd least field for it to work with.  That's why the Raibeam doesn't
> > have a conventional reflector--it design doesn't need one due to it's
> > clever design.  That now unused element spacing is used more effectively
> > in front with another director for the 3, 4 & 5 element Raibeams.  As I
> > have said before, this is the first real improvement to a yagi since
1922
> > as it gives absolute maximum gain for the length of the boom.  The
Raibeam
> > also holds it's pattern and low SWR over a wider frequency.
>
> A Raibeam is simply a two-element phased driven array with
> optional additional directors.  I had a similar antenna on 40 meters
> in the 80's. It has high f/b if adjusted correctly, but basically no
> more gain than any yagi on the same size boom.
>*******Since you haven't actually measured it on a range how would you
know?
>
> One model does not verify a "rule", it only verify's the one
> circumstance modeled within the limits of the model.
> ****That's true so I used the worst case--3 different resonant guy wires.
I
>think even you would admit non-resonant wires would have far less affect.
>Would you?  I'll forgive you if you do.  You know at times I've had the
>fleeting desire to have an eye ball technical discussion with you.
>
> I deleted the rest of the talk about baluns (and a few personal
> snipes) because two or three topics in one post are enough.
>*****No let's let it all out. We have had many so far and I've been told it
>has been very informative and entertaining by many.  Even my phone is
ringing
>with support.  I've been on it all night.
>
> So tell me, how many cases did you model to confirm your
> K7GCO rule always works? Can we expect other tower owners to
> go out and remove the insulators breaking up their guylines with no
> ill effects, as long as those guy lines are 1/2 wl from the antenna
> and tower?'
> ******I've told you a couple of times already (count them) and it's a bad
>concept to think someone is going to remove whatever insulators they
already
>have in the guy wires.  I have only suggested having Phillistran for a
>minimum of a 1/2 wave from the tower--longer if you want to!  Suggest
changes
>that "serve a useful purpose."  Now lets get off this picky guy wire
routine.
> The case is closed except for more constructive research.  I only
recommend
>and give away what cost a lot of time and money freely what I have found
>workable from my extensive data in all areas.  It's solely up to the
>individual if he wants to try it.  Since the price was right--give it some
>respect.  You didn't lose any money on it.  I can get a lot of my stuff
>printed, can get paid for it and already have requests for it.  I've had
over
>250 articles printed, given over 450 technical talks at Conventions and
Clubs
>since 1946 in 3 different technical fields and so far no errors or
challenges
>except from you.  You are free to keep trying but do it privately.  Lets
keep
>the information channels open without your constant reticule if you
>disagree--in particular without supporting data.  I'll get you up to speed
in
>no time at all.  K7GCO
>
> 73, Tom W8JI
> w8ji@contesting.com
>
>
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