In a message dated 6/11/01 2:51:14 PM Pacific Daylight Time, aa4lr@arrl.net
writes:
<< On 6/8/01 5:10 PM, K7GCO@aol.com at K7GCO@aol.com wrote:
>used no TT Band Aids and have spent the .....
^^^^^^^^^^^^^^^
This seems to be a catch-phrase for you, Ken. You've used it in several
messages.
Frankly, I've been a charter member of TowerTalk (virutally) since it's
inception, and I've never seen anyone advocate any "band aid" approach
to
tower or antenna design.
Indeed, the governing phylosophy of this list appears to be to do things
RIGHT. Doing the job right often means it costs more, but there are
substantial dangers to equipment, property or life doing it any other
way.
Now, prop-pitch rotators are most definitely over-rated for the vast
majority of tower installations, so it is no wonder that they perform
superbly in that service. They are also as scarce as hens-teeth. And
expensive.
I'm sure your 55-year-old prop pitch rotators will be giving fine
service
to your grandchildren's heirs, but not all of us can afford, nor need
them.
The new bell-housing rotators are also absurdly expensive, but it is a
lot easier to find used ones in servicable condition, or to bring back
one to condition yourself. (My Ham-M cost me less than $50 recently,
plus
a couple hours of work to service it) If a few aerodynamic tricks make
the bell-housing rotators perform better, that's not a "band-aid", but a
good idea. Let's save those prop-pitches for when we really need them.
I thought no one would ever ask. It applies to fixes on mostly an
"inadequate electrical or mechanical design or equipment". "If something
needs fixing or beefing up--It's inadequate." (Old K7GCO Axiom)
I've used the "Catch Phrase Band Aids" about 50 times in the past 1 1/2
years relating to just specific repairs to what it infers. What have you
been reading? I had a specific discussion with you on this very point where
you were defending the use of rivets in general and 2 in line to secure
telescoping elements when the larger one is less than .058" wall. The
element is relatively rigid in only one plane where with hose clamps it's
rigid and secured it in "ALL 360 Degree Directions". Aluminum pop rivets of
the diameter used are not a secure device for something with stresses--24 hrs
a day. Hammer rivet (not pop rivets) are more secure if large enough and are
used in airplanes. Getting behind them with a bucking bar is impossible
inside elements. As a Quality Assurance Engineer at Boeing I worked with and
ran failure tests on all kinds of rivets and know exactly all of their
limitations of each and every design which I tried to get across to
you--repeatedly at the time with no success. TT was full of "Failure
Reports" which should have been enough to convince you of their limitations
yet you continued to defend them. The manufacture even eliminated the use of
some of them. They are fast and cheap to use in manufacturing and kit
building but don't hold up unless they are what I call are "over size" and
even then I don't use them on antennas where things can wiggle 24 hours a day
with various loads on them. "They Failed"--that's the "Big Clue" of
inadequate design. "Longevity and No Maintenance" should be the design goals
we strive for and demand from manufacturers. I've been oriented that way
since the 30's as a nickel a day allowance (and what I could earn) "Radio
Pension" had to be stretched as far as I could during the Depression and WWII
where there were "no replacements." I still have my original open wire line
I made. It was very cheap to make, has the "same low loss now" even with
high SWR it had back then and now, doesn't need all those charts telling of
"increased loss in coax with higher SWR on TT" and has never needed a repair.
Come to think of it I did break a spacer one time. That open wire line has
probably carried more RF than any ham feedline in history. I've broken a
wire on another open wire line and a "soldering job" was all that was needed.
Actually coax is just a fad and will go away. Hold it I'm just kidding.
Some have taken that seriously and got all upset. Open wire line (the good
stuff) is now being sold you know. If you learn how to use Antenna Tuners,
certain feedline lengths, techniques I suggest and don't listen to the poo
pooers who haven't, you might like the results. All those fancy and very
expensive coax connectors for the big expensive coax just go away. I'm
trying to save you money.
A recent "TT Band Aid" discussion had to do with the Prop Pitch Motor or I
should say the "lack of use of it" from my standpoint. There have been many
many discussions on all kinds of extra beam, rotator, guy and tower stresses
when a beam is unbalanced to the wind. All kinds of math lessons are given
on wind loads to tower and beams--on and on. I can do the math but I haven't
had to all these years because I had the good sense or luck from day 1 to use
properly guyed (sometimes with ropes) (and self supporting towers to
eliminate guy wire problems dominating TT now) that were perhaps over rated
and PP rotators that were overrated by your standards. I can't buy your
statement "let's save those prop-pitches for when we really need them." From
what I read on TT we need them NOW properly installed.
I beef up booms and elements in the middle so I don't even need cable braces
(another Band Aid with inadequate boom design initially at least on 20M and
up) and with my selections they have taken all the winds even with ice
loading for some 55 years. I have the same rotators and other parts "still
working and undamaged." You need a "realignment of your ratings and
standards."
Rotators are purposely underrated so that TT would be full of all kinds of
rotator problems and they would have more of your money over time. I like
"one time purchases and NO maintenance." One rotator mfg asked me for one of
my proven Antenna Tuner Designs to mfg. He didn't want to pay anything for
it either? His rotator designs were and present employment business
practices for another company now are on the cheap side also.
Any rotator by my standards that lasts 55 years with no signs of wear with
all kinds of loads (some unbalanced) "is not over rated." It's rated just
right. Smart hams should make every effort to use them and cultivate this
type of thinking. They will save a lot of money. I have 8 PP motors and
every damn one is converted to higher speeds than 3/4 RPM which I have no
patients for except for a 75M beam--someday I'll have one. I use 2-6 rpm
depending on the size of the beam. I hear of all kinds of horror stories by
those who have "never used a properly designed PP system." You would think
that by now I'd have found a few or "even one problem they absolutely insist
I have"? I say 1 RPM is just enough to not be too slow for most and not
require bigger gears and brakes--in particular if faster. I say that is a
"Band Aid Design" and TT is full of all it's problems. I speed up even
commercial rotators and just don't over load them. I speed up even the small
TV rotators and it's a joy to see TV antennas spin at 4-5 RPM. I can peak an
unknown signal real fast even with a 2 element beam. I've a couple thousand
patterns or more on paper and by watching S-meters which I wouldn't have done
without a fast rotator. I have Eznec patterns I check out on the air
inparticular for "nulls" and haven't found a lot of the "null fill in
surrounding objects" (that many go to great length reporting on TT) in actual
practice and in Eznec. The biggest problem is "RF Spill Over" of what I call
"Band Aid Feed Systems" the creator of it and it's sins which no one else has
addressed. Use balanced feed systems and many problems just go away. That's
why I like balanced 100 ohm coax into FD DE's on beams and quads. Balanced
1/4 wave stubs can be made of several Zo's to use for lower Z feedpoints on
yagi's. With "link coupled tank circuits" one can match a balanced or
unbalanced feedline from 30 to 1000 ohms. Receivers had balanced inputs
years ago. So in some cases an Antenna Tuner is a Band Aid. It is needed
for Z loads above 1000 ohms at the end of an open wire feedline when using
link coupling or a Pi. Actually there is a way with Hi-Z loads to couple
directly to the tank with 2 capacitors.
I just paid and all time high of $50 (he wanted $75) for a medium PP motor
at a flee market and there were 3 others there I felt overpriced--$100. You
can certainly afford that. You just need to know how to use them. It was a
real mechanical joy converting it and I took a lot of digital pictures of
each step although I had plenty from the past. I may publish a Prop Pitch
Motor Handbook and may do a Maintenance Service on them later as beams are
getting bigger and Slow Band Aid Rotators are getting real expensive. It
appears there will a market for this info. I just don't understand why you
say "lets save the PP motors for when we really need them." What's wrong
with using them NOW when they would be the cheapest and have "strong
mechanical rotator clout" (new term I just created) which is always needed.
Many have to be dragged kicking and screaming into better ways of doing
things in many areas.
If "no one is advocating a Band Aid approach to towers and rotators" as you
claim, how come so many are having so many problems? A good repair to
anything is great if it lasts. Use bigger stuff than recommended and
problems go away. There are "No Relectors for PP Motors" and other
adequately designed products. I plan to have PP motor info on a future Web
Site for conversion and use--not repair unless improperly used.
I got most of my PP motors real cheap like $10-20, so in 55 years I don't
have over $200 invested and only one maintenance job where water got into one
not properly protected. I overhauled the rusty bearings and it's still
rotating. I was recently asked how I kept the water out and I answered him
by E-mail in absence of a quick picture. PP Motors "are not scarce as hens
teeth"-- I see them at every flee market at good prices and when I get time
I'll buy them up, overhaul them and makes some money.
Other TT Band Aids are the transmission line coupling from a BMW to soften
wind torque's on rotators. One TTer suggested another Band Aid of a 40' mast
pile into the tower to "give a little." You don't need all that with a PP
Motor. All this has been known for years.
All the concrete problems and heavy math that dominated TT are interesting
and needed for certain installations. I have suggested telephone poles
repeatedly with a 2 wire track on the side. You dig a hole and have the
Power Co drop it in, fill in the dirt around it and you are done in a hour or
less. Be sure and take care of the driver and crew with a few bottles of the
proper spirits. If you move, cut it off below the ground level with a chain
saw, sell it locally and throw a can of "Stump Remover" on it. The only math
needed is what was needed to "Buy the Spirits." The widow doesn't have the
problem of removing the concrete block in the ground either. Telephone poles
are far more acceptable than towers to neighbors I've noticed.
There has been big discussions of guy wire interference to beams on TT. It
does occur and I gave simple solutions. I have suggested connecting unbroken
up guys to the top of the tower is not a really smart way to ruin a pattern
and a major dumb dumb many repeat. Who says guys have to be connected to the
top of a tower?--Weak tower Mfgs do. I say that "if your guys can't be
connected 10-15' below the top of the tower--your tower is too weak". The
lower connection will reduce guy wire interference although I would still use
a 1/2 wave of Phillistran before the wire guy just to be on the safe side.
Lower guy connections also make it a a lot easier to install a beam
A yagi's basic design involves telescoping joints. I and many others found
over the years, joints become lossy and capacitive. I developed a cleaning
process for the problem as needed. I then used the various goops and found
they helped but some would eventually fail and get hard enough that a file
was necessary to remove it. I have ways to check beam performance with
pattern recorders. I've used a capacitance meter and a HP low resistance
meter on the joints. A regular ohm meter is all you really need. It will
show you if the joint is capacitive also--the Xc value is irrelevant. So I
got tired of that nonsense and now use a flee market solder on the joints and
I have "ZERO Maintenance and ZERO Resistance" on the joints--continuously. I
believe I'm the only yagi user that can make that statement and yes soldering
the joints could be called a "Band Aid Fix" but it lasts. It's the only way
to solve the joint problem 100%. Prior to soldering the joints I had a "Saw
Tooth Performance Curve" created by regular cleaning. I have run adhesive
backed aluminum and copper tape over the elements with good results. I've
cut long strips of copper sheet, coated it and the aluminum or fiberglass
elements with contact adhesive and stuck it on there. You can still buy
this. I rotated it slowly in the lathe and wrapped plastic tape around it.
Shrink on tubing is too expensive. I noticed reductions in feedpoint Z's and
a slight resonant frequency change with the copper wrapped elements. This
adhesive backed aluminum tape is ideal for a strip across the double folding
joints on TV antennas in the center in the high current area. It's
convenience and necessity for shipping would get very resistive. This would
show up when running TV antenna patterns.
Quads have a "Straight Line Performance Curve." The joints are soldered and
there is "never any performance deterioration". I'm "yagi'd out" after all
these years, have a family of good designs, and am switching to new
challenges with quads. Quads are also very easy to scale to the100 MHz FM BC
band (or any band) to use RF sources that are on 24 hours a day from all
directions and you can use your FM receiver as FS meter. The reason they are
very easy to scale compared to yagi's is that wire sizes come in very close
steps. Model airplane tubing doesn't. Spacing and length are easy to scale
with both, diameter steps aren't.
I like PFA's-- "Permanently Fixed Aids" and "Controlled Buying and Other
Pressures" that forces manufacturers to produce better stuff. Then a
"Reflector for Fixes" isn't even needed. E-mail is 50 times more useful than
regular mail. Lets make the most use of it which we still can before they
tax it.
I'm just trying to save you money and wasted maintenance time. There are
many more Band Aids I could have mentioned but I think you and others should
have got the message by now. Bill, do you have any further question? K7GCO
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