Hi All TT's;
I agree with Ken on this one. The K7GCO hand RF burn test hurts. He is
correct.
Bill KC4UZ
----- Original Message -----
From: <K7GCO@aol.com>
To: <towertalk@contesting.com>
Sent: Friday, June 22, 2001 5:45 PM
Subject: [TowerTalk] Re: Stray RF yes and no
> "STRAY RF--YES & NO!"
> This was sent to 23 others before to TT for their comments. No one had a
> single problem with it as they had found the same things I have. I wanted
> thank the others who confirmed my contentions that a lot of beam
interference
> from guys etc was actually and mostly from other stacked beams if too
close,
> RF Spill Over from bad matching systems like some badly adjusted Gamma
> Matches or coax direct feed to balanced feedpoints without a balun.
Symptoms
> frequently gets misdiagnosed! Sometimes you get some surprises. There is
a
> simple way to fix or balance the affect of a gamma, however. Shift the DE
> center and adjust the tip lengths and use the "K7GCO Stray RF Hand
Test"--it
> works contrary to those who haven't tried it. Some changed to balanced
100
> ohm coax and a T Match, FD as I suggested (I may get something very useful
> started here), better baluns or baluns like a 50, 100 or 160 ohm Bazooka
for
> balanced feed points and--the SWR change with rotation problems for
one--just
> went away! Isolation to SWR changes is great but may not be enough. If
you
> have an accurate E plane pattern of your beam from the manufacturer or
Eznec,
> you can at least check out the E Plane by rotating the antenna. However
RF
> Spill Over can still affect the H plane pattern and often not see it on
the E
> plane. After measuring vertical patterns for years I can assure you It
can
> be very evasive.
>
> In one interference case reported to me an insulator at the tower for the
> guys solved the problem--or at least part of it. Lowering the top guys
10'
> solved the problem in 5 other cases. NOTE! I see absolutely no reason for
> guy wires or Inverted Vees at the top of a tower anyhow. If you can't
attach
> the guys 10-15' below the top of the tower--your tower is too damn weak.
I
> don't know how this ever got started? A big 40M beam on top may be an
> exception. A staggering question is, "why haven't others suggested this
same
> thing repeatedly"--it's so "incredibly obvious." So many bad practices
like
> this get started and too many follow like sheep over a troubled cliff that
> even the TT Reflector has trouble handling. Those trying to redirect the
> traffic with "new practices" away from the cliff edge often get ridiculed
to
> oblivion also. Progress is often made "One Death At A Time."
>
> Stray RF can certainly do it's damage to F/B ratios if just right.
However
> it can be controlled and even ignored at times as the reports continue to
> come in who followed my instructions. Actually nulls more than 30-40 dB
have
> "no legitimate reason for existence anyhow." They are usually in a real
> narrow slot, very difficult to use anyhow and are inserted into patterns
by
> mother nature just so that the "RF Straw Bailers" (those who grab at stray
RF
> straws excessively) have something to crow about and look smart. They are
> kind of like the "ACLU of RF Human Rights". Their claim they "Defend Your
RF
> Rights" (nulls) like no one else but there are 3 other (nulls) the ACLU
> absolutely refuses to defend like the right to own guns and 2 others the
> Liberals don't like. Hey that's a pretty good example if I say so myself.
>
> I shall give a "classic example" of an "extreme case" that few thought
would
> be possible and apparently haven't realized it's full significance as yet.
> Lucky I didn't listen to them before I started my project on a 5 and then
a 6
> band quad. Antenna Mart has been making all band multi element quads for
> some time with great patterns. The "Stray RF Interfering Elements" in
> question here are even:
> 1. In the same plane
> 2. Resonant on each side of the operating frequency
> 3. Of the same polarization and
> 4. Very close to if not optimum spacing (optimum spacing
> may not be used by the main elements).
> NOTE! These elements are capable of reflecting
> "Major RF"--not "Stray RF."
> It's a "5 band quad (20-10M) using tapered spacing (I've added 6M with a
new
> twist--why not)." However it uses "individual DE feed" with a remote coax
> switch on the tower like Antenna Mart does--the DE's are NOT all tied
> together which totally destroys the potential pattern "beyond repair" (in
> Eznec and on the air) with all this "Stray and Major RF" used in the wrong
> technical and financial way in business. Some manufacturers actually sell
> this "Junk Stray RF Beam" to unsuspecting hams without a whimper even when
> told about it. I seldom had to rotate the beam on CQ's even though a DX
> station would call me on the side or back. Why hasn't any of the "Stray
RF
> ACLU Experts" on TT got concerned over a real "Major Case of Stray
> RF--Industrial Strength??
> Paul Harvey said:
> "We live in a Junk Society. We have Junk Cars, Junk Houses, Junk
> Books, Junk Toys, Junk Movies, Junk TV's, Junk TV Programs, Junk
Furniture,
> Junk Food and one city even had Junk People--they had more Suicides than
> Homicides." We even have Junk Sex--it's less Emotional Satisfying and
Junk
> Antennas, Junk RF, Junk Radios, Junk Other Ham Equipment--on and on. They
> even sell you Warranty Insurance to help pay for the eventual repair!! I
> have returned the last 14 items I have purchased including 3 ham rigs with
> major and expensive problems, cameras, an intermittent telephone, lenses,
> guns with dangerous design flaws, an $800 Cell phone 6 years ago, a
> Fax/Telephone combo on and on--junk junk junk. Some Junk Designs hang on
for
> years like the Gamma match. It's taken me a while to wake up but the only
> way to eliminate this junk problem and wasted money is--don't buy
anything.
> I'll keep the 3-6M Raibeams as they are built and work great--better than
I
> had expected. A tight wad friend of mine who never buys anything brings
this
> to my attention all the time like for over 45 years. I had to admit to
him
> he's been right all this time. He's got over a "million trouble free
bucks
> in stocks and bonds I don't" and smiles a lot also.
>
> Tom Peters used to give talks on "Making Life Time Customers" and I have
his
> and other books on it. It's become almost a "Forgotten Concept." There
is a
> concept frequently used now by many businesses where, if you get a
"lemon,"
> you're told "you will eat it." That's a very tough and sickening thing
for a
> retiree, a kid or anyone to hear with their hard earned money invested.
You
> couldn't get away with that years ago and still can't from some buyers.
I'm
> told "they often still come back" so they feel justified in doing it and
the
> "lemon product" is a headache for them also. I can show many proven
> statistics that is "still bad very business." It still makes "Stray RF
> Customers" in the Ham World. Walmart like no other Merchant has made
> millions and millions forcing (ruthlessly some claim) suppliers to supply
> good products at a low price. Mass sales at low profit margins has made
the
> "Biggest Fortunes" like for Walmart. Perhaps the Ham Dealers should do
the
> same. I think pressure should be put on the Junk Manufacturers of items
for
> resale or direct sale. Don't buy them! Don't throw your money away.
>
> KC6T had a great article in QST where he tuned up a 5 band quad and used
> series fixed and selected capacitors for the final reflector length. His
> buddy did the same with a series inductor with taps. I guess the
reasoning
> was--it was easier to make a change in the reflector bottom wire during
the
> initial tune up from the roof than it was to change the entire wire
length?
> Regardless both got it tuned up and it still worked great after the move
from
> near the roof (house wiring, eve troughs and all that) to the top of the
> tower-for both. How could that be?? It happens when you learn that there
> are fewer design restrictions than you have been led to believe by the
"False
> RF Prophets." In this design the reflector was slightly larger for the
> series Xc and slightly smaller with the series XL than normal when
properly
> tuned. This design actually used the same physical spacing on all bands
with
> good patterns although I will compare it to tapered spacing.
>
> About 40 years ago Sant G2PU found that the usual open wire shorted stub
used
> for convenience to tune reflectors, "canted the free space H Plain Pattern
> off center line" (either up or down I don't remember). Reflection Factor
> plotting with the free space pattern when tipped up or down will reduce
the
> potential reflection 6 dB gain main lobe like over what I call "Liquid
Copper"
> --Salt Water. Your antenna creates the "text book nulls" in the beams
> vertical pattern only over perfect ground and salt water is as close to it
> you can get. Normal ground loss fills in the nulls bit more and for
vertical
> polarization, the even higher ground reflection losses fill in the nulls
and
> reduce the gain even more. The higher the frequency the worse it is for
both
> polarization's for the "Highly Abused and Misunderstood Null--It Gets No
> Respect." However, Nulls or Dips in the pattern will put up a pretty good
> fight to survive in the E-Plane I've found and have some great
configurations
> of beam patterns for verification. The reason all those great nulls are
> shown in text books is conditions are ideal on paper. There is no RF
Spill
> Over on paper--it's non conductive. Would you believe that if technical
> books were printed on aluminum foil, lift off of vertical patterns and
> fill-in of nulls would be shown?
>
> G2PU discovered the canting of the free space pattern when he fed his 20M
> quad vertically polarized with the single reflector stub now on the side.
> His pattern on vertically polarized sources "was not head on" and easy to
see
> on the S-Meter. So he said "enough of this design compromise total
nonsense"
> and took out the stub and lengthened the reflector until he got the same
> pattern--head on. Then he rotated the feedpoint 90 degree back for
> horizontal polarization with no tipping of the free space pattern. You
can
> have equal length stubs on each side for balanced but why have stubs at
all?
> They just flop around in the wind. After tune up they have served their
> useful purpose. Add their length to the reflector.
>
> How much difference a single stub actually makes on typical contacts would
be
> hard to tell for sure with other than 2 Quads side by side, one with and
one
> without the reflector stub. Eznec will tell the difference also at least
at
> the RF Starting Blocks. I'm sure it made at least an S-Unit or 2
> psychological difference to listen to him tell about it although he always
> had a great signal on AM with a 2 element quad on 20M. I haven't heard
him
> lately although he's still in QRZ. Too many design and performance
> compromises are often used for convenience or to save money. Too few
design
> for "Maximum RF Clout" like Raibeam, Antenna Mart and M2.
>
> Now even with no tuning stubs, no metal guys and individual feed of quad
> DE's, it would still appear listening to all the "TT Stray RF ACLU
Experts"
> it would be totally impossible to get a 3, 5 or 6 band quad tuned up on
ALL
> BANDS and have good patterns with good nulls. It would seem there are
just
> too many stray RF generators and are too close in the wrong place. Are
you
> sitting down--NOTHING COULD BE FURTHER FROM THE TRUTH!! Don't you "Guys"
> ever get tired of being wrong? All 5 bands (even 6) using .125 WL spacing
> tuned up with great patterns and nulls with tapered and fixed spacings.
> There were a couple "Unexpected Bonus." The gains increased slightly and
> even the F/B in some nulls over what was possible from a monobander. It
> never got worse. I reported this on TT and all the poo poers came out of
the
> computers with their ho ho ho's. Then Cebik bless his soul, verified what
I
> had found as he had found it also. The Poo Pooers were "strangely
silent."
> It was then he told me of KC6T who found good patterns on each of the 5
> bands. He uses the same physical spacing in his design. This is what is
> actually found when someone actually spends some time "tuning up beams"
> instead of their "TT Shooting Gallery Opinions."
>
> The H planes of yagi's and quads are always larger than the E plane in
every
> pattern I've ever seen. I have never ever seen it the same beam width
except
> in a Bi Square "totally unexpected bonus"quad. They get real close in 7
and
> 8 element yagi's. Another was this. The 6M 2 element quad inside the 5
> other bands with symmetric loops--had the "Same Beamwidths." Absolutely
> Incredible! This is "Pattern Black Magic." There was just too damn much
> Stray RF. We just have to pass a "TT Anti-Beneficial Stray RF Law." So
Be
> it! It's not "Technically RF Correct." It's totally out of control in a
> beneficial manner. We can't have that! Someone may have a signal edge.
In
> "RF Socialism" everyone has to be the same.
>
> How could near resonant elements of a 5 or 6 band quad on each side of 3
or 4
> operating frequencies be so immune to the beams pattern? It's violating
too
> many "TT Opinion, Appliance & Band Aid Operator Laws." Embarrassing isn't
> it? Elevated Egos will never be the same.
>
> When all the 5 band quad DE's are tied together, high levels of RF are
> clearly seen on other off band-elements in Eznec and it does indeed affect
> the patterns. It's so bad the 10M free space pattern even tilts down at
> about 35 degrees--very grim! That's "Major Directed RF" doing this, not
"TT
> Stray RF."
>
> There are many other examples I've seen that just aren't doing hardly
> anything but then there are those that do like a towers affect on a
> vertically polarized beam. I know all the major ones and have battled
them
> for years. They are clearly seen in a pattern recorder. I just found a
new
> one just spinning the beam that has been unrecognized even with Eznec now
and
> will report on it. Under "perfect conditions" I felt I had a vertically
> polarized H plane pattern upset with stacked beams with certain spacings.
RF
> got on the separating boom of the wrong polarization. I found the reason,
a
> simple solution and solved the problem.
>
> With individual DE feed of 5 or 6 band quads, some RF levels are actually
> shown on off-elements in Eznec and recorded in the Current Charts. Yet
great
> patterns result which absolutely defy TT common misguided opinions.
>
> I also excited the higher and lower frequency DE than Fo and great
patterns
> still were maintained--some even better. I was surprised myself but I dig
> into areas that few would think productive all the time. It blew up the
> theory of resonant DE's were needed other than for a resistive feedpoint.
I
> had thought of feeding the quad with open wire line and this off band DE
> would be reactive one way or the other depending which one was used. I
felt
> the Match Box could handle this from the Z's I saw and similar examples.
> That's an interesting concept of feeding the off band DE and getting a
great
> pattern. More on this later.
>
> It's my plan to add a "new performance wrinkle" to an all band 2 element
quad
> by adding variable Xc's in each reflector all ganged together to a selsyn
on
> the mast so I can tune for max F/B or Gain anywhere in any band on all
bands.
> I'll determine the free space pattern cant if any of the H Plain in Eznec
> and tilt the boom accordingly to compensate. There are little tricks away
> and around some problems and in some cases certain levels of "The Dreaded
> Stray RF Isn't All That Bad" even right in the bedroom under the sheets so
to
> speak. If you learn how RF really flows when and where, what different
> levels do, you can learn how to talk to RF figuratively speaking--it will
> behave.
>
> I'll feed this quad with 100 ohm balanced coax into a match box in the
shack
> which will assure max RF into the coax input and anywhere in the band with
> whatever the configuration is used. That could be considered a very
useful
> feature--in particular in a contest and no beam has it yet. Although guy
> wires are out of the main plane, often non resonant, of the wrong
> polarization, spacing and sometimes in a pattern null, I'll run some guy
wire
> stray RF tests in the pattern and SWR curve when I rotate it just to ease
my
> and other's curiosity in case they ask--or demand. I leave no RF Stones
and
> RF Burns unturned. A lot of all this was determined, observed and made
use
> of by many even long before Eznec so little of this is really new info.
>
> While I'm on a roll here I really like 1/2 wave verticals whenever
possible
> in particular on 40M and on up for many reasons. I've had a couple of
> articles on these 1/2 waves in CQ some 35 years ago. All these radial
> problems go away although a screen around the base when close to the
ground
> has been known to help--even at WWVH. If the base is high enough the
ground
> screen could probably be done away with. I'll try it with and without. I
> use 1/2 waves with an another unusual but simple design now on top of
> monobanders for "listening antennas" as my F/B patterns are so good on
some
> beams (even with stray RF guys) I'd miss a lot of stations off the back
and
> side without the 1/2 wave vertical to switch to. I can run them together
> with different phasings. It often does great just by itself. I've used
1/4
> wave verticals over the beams DE also as the radials. Why this hasn't
caught
> on I'll never know.
>
> I have a 6M 1/2 wave on the roof now for monitoring. The 6M Raibeam 5
> element "Butt Kicker" I have 30' higher has such a good F/B/Side (even
with
> 2-6M beams below it), I needed the 1/2 wave vertical for monitoring.
When
> an opening occurs on 6M you don't want to miss it from any direction and
it
> can be weak. NOTE! If certain of my or the 5 element Raibeams unusual
> F/B/Side ratio's wasn't as good as it is, I wouldn't need the 1/2 wave
> monitoring vertical. Apparently many have never had a beam with
exceptional
> F/B/Side!! What have you been doing all these years in advancing the
state
> of the art? Show me some examples. I have some that I haven't even
> mentioned yet.
>
> There is a "reverse concept" I have observed. I've told of the 10M 3
element
> I have tuned for "absolute max gain of 10.2 dBi." No manufacturer has
ever
> tuned a beam that way. It has 8 dB F/B, narrow bandwidth and 6 ohms in
the
> center of the DE. The director is actually longer than the DE. I feed it
in
> a sneaky way at a 50 ohm feedpoint with "Absolutely No RF Spill Over."
The
> coax shield and center of the DE attached to the boom is "RF Stone Cold."
> Would you believe that a "RF Frost" appears there after a long
transmission.
> Another phenomena occurs with 8 dB F/B I didn't expect. After a
transmission
> running legal power the back lobe clears the frequency so well it leaves a
> "Signal Black Hole" for the same length of time before it fills in.
That's
> "Infinite F/B." In 3 years using the beam I don't remember having to
repeat
> anything. Contesters find this useful and have been known to have another
> final on a beam pointing the other way leaving the impression or stating
they
> have poor F/B. Now you know. With a beam where max F/B and/or Gain can
be
> selected, one could also transmit with max gain and listen with max F/B.
> That's a great idea.
>
> This beam has another great advantage. With poor F/B you don't have to
worry
> about Stray RF filling in the nulls--it might create one--heaven forbid.
It
> could really silence the "Stray RF ALCU Birds" forever!
>
> Antenna design is very interesting if you learn how to massage the RF and
put
> it to work for you. Few know the joy of a "fast rotator and a great beam
> pattern. When you call them--they stay called." And I now have 3 ways to
> cure and extend the narrow band width of this or any beam even more.
>
> I had a 5 element 6M yagi on a 16' boom 10' below this 10M beam and when
> installed it didn't change the SWR a bit of either one. The vertical
> patterns of each and the very tight max gain coupling between the 10M
> elements apparently really isolated it from the 6M beam. Both worked
great.
>
> I worked KE6IHA on 6M using a Cush Craft Ringo vertical that is really an
> "Extended Double Zepp" of 3 dB gain design like their 2M Ringo. Running
700W
> he has worked a lot of DX on 6M using it much to my surprise. That's one
of
> the few reports I've had of this although I know very well what 1/2 waves
> will do on all bands--except 6M. This caught my immediate attention.
I've
> only heard JA's for DX 2 years ago on 6M once although they were coming
into
> Seattle last week and I missed them. My 1/2 wave will be mounted on top
of
> the 5 element Raibeam shortly. I want to see how well it will work up
there
> at any distance on 6M. I will then make my version of the 6M Ringo. The
> Ringo is actually a very poor design. The ring at the base is really the
> inductor of a tank circuit to match a Hi-Z at the end of the antenna and
> tapped at the 50 ohm point. But it has the highest RF Spill Over down the
> mast of any vertical in Ham radio. The higher you mount it the worse it
> works as more of the lift-off of the vertical pattern occurs. The mast or
> tower is heavily excited like a long wire and dominates. When the 2M AEA
> Isopole came out with the double radial skirt to kill RF Spill Over once
and
> for all, Ringo added radials below the Ring Tank Circuit. Unfortunately
they
> didn't understand exactly what they were doing and trying to copy it,
added
> radials 1/8 WL lower and not 1/4 WL lower at the maximum high voltage and
> Hi-Z area where they are the most effective as "RF Spill Over Killers."
They
> were close but "No Cigars." When I told them "they missed by 1/8 wave,"
> their eyes rolled. I don't think they understood what I said as they
didn't
> change it.
>
> A local Marine Antenna Manufacturer has a similar "pattern lift off
problem"
> with a the 156 MHz vertical and don't know why. These pattern lift off
> problems created by "Major Stray RF" are still virtually "Best Kept
Secrets."
> The previous owners had stolen an antenna design from me and it had RF
Spill
> Over they didn't know how to stop and had then had the guts to ask me how!
I
> will offer a solution to the new owners for a respectable fee. I applied
the
> fix to one of their type antennas that can't be seen on the outside, will
> demonstrate and then we will negotiate. I hope I get out of there alive
and
> with some folding stuff.
>
> The Ringo, the 2 Marine verticals and several others including some Ham
> verticals on the market are really nothing more than:
> "50 ohm matching devices for the coax to the mast."
>
> "So it can be seen that 1:1 SWR is not the full picture in
> evaluating an antenna with or without Stray RF but
> it's a good place to start."
>
> It's like kissing on the hand--you have got to start some where!
>
> The frequently neglected, hard to measure and evasive vertical pattern is
> very important. The key to performance is seen mostly in the free space
> vertical pattern--is it at 0 degrees or on the horizon? Learn how to
> evaluate and control it once mounted on a tower. Dominate signals can be
the
> result. You may be accused of running big power. I know the feeling.
> Record the weak DX station and play it back or point out "you hear the
weak
> ones better than they do or not at all." Sometimes they will call you
from
> across town (and across the country) to see if you are talking to
yourself.
> They "Absolutely Fry in Their Frustrations" hearing on the phone what they
> don't hear. Bill Wall has had that happen using his quads. That's a big
> clue you have got an unusual beam. Unfortunately few will ask how it is
> done? They will ask about the receiver and seldom about the antenna?
>
> Another clue of Stray RF and beams too close to each other is RF in the
> Shack. If Compression is used on SSB Stray RF there can easily get into
the
> audio in some rigs. This usually happens when no balun is used.
>
> Summation: All Stray RF isn't all that bad as some have claimed. If
it
> was the 6 band 2 element quad wouldn't be possible. Proper design does
> reduce it as much as possible.
>
> I've covered most of bases in this post to suppress most of the nit
pickers.
> I did add something a sharp nit picker could jump on. Let's see if any of
> them catch it? I put something in for everybody. K7GCO
>
>
>
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