------- Forwarded Message Follows -------
From: al511@freenet.uchsc.edu (Robert Neece)
Subject: possible e-mail to cq-contest
To: al019@freenet.uchsc.EDU
Reply-to: al511@freenet.uchsc.edu
The reflector has been rich with valuable commentary on guy anchor posts.
For the most part, the comments have been anecdotal, in the
vein of "this is what has worked for me." Few comments have been
truly analytical or quantitative in nature. This is not necessarily a bad
thing. Many of us prefer seat-of-the-pants overkill to having to engage
in what might be a tedious (and perhaps expensive) rigorous, quantitative
evaluation of the relevant mechanics. We want to avoid unreasonable
hazards. All the same, we want to erect some metal and get on the air,
sooner rather than later.
The comments on the reflector reveal quite a spectrum of experience with
elevated anchors. Successes, though, appear to outweigh failures by a
substantial margin.
I am the last person who would be inclined to overlook probable failure
modes. But some of the comments express a concern over possible failures
that I myself have not known to occur. I'd be interested, therefore, in
more information about actual failures. This might better inform us about
where, on the basis of experience, problems are likely to arise, and
better prepare us to avoid them.
I am curious, for example, about the basis for a few of the comments
posted in recent days:
>> Do use galvenized Steel I-Beams, rather than tubular, due to
>> breaking strength.
Does this imply that tubular steel pipe of proper characteristics has so
low a breaking strength as to render it the weak link in the chain, that
is, that the pipe may be predicted to fail before the guy-wire material
itself? I assume that by "breaking strength" the writer means not the
*tensile* strength of good steel pipe (which one might assume to be far
greater than the tensile strength of even EHS cable) but, rather, that the
pipe might bend where it enters the concrete, and fracture at that point.
Has anyone seen this happen? If so, how high was the pipe out of the
ground, and what kind of pipe was used?
>> Do go as deep as possible. (100' tower, I'd go minimum of 10 feet!)
One must grant, I am sure, that the needed depth for a secure anchor is a
function of, among other variables, the nature of the soil, the load
presented by the tower and antennas, and the height of the anchor point
above ground. I know of several large installations (150'+) in
severe-wind environments that have survived for decades with anchors no
more than five feet deep. I hasten to add, though, that those
installations are in stable, rocky soil, and the above-ground height of
the anchor is no more than five feet. What is the deepest anchor anyone
has seen pivot in the ground? What kind of soil was involved? What were
the other operative factors?
>It's important that whatever you use as a "post", should have some sort
>of plate or rods tied in at the bottom so that it has no chance of
>pulling out of the block of concrete.
I have been assured by people whose knowledge and judgment I trust that
the adhesion of properly prepared and cured concrete to a large-diameter
steel pipe that is imbedded deeply enough in the concrete is an amazingly
great adhesion indeed. This should obviate any material advantage to
attaching bottom fins or plates to the post. Is my information unsound?
Does anyone here know of an instance in which a pipe pulled out of the
concrete itself? If so, what length of pipe was imbedded in the concrete?
I am afraid, by the way, that the rigor of the specifications provided by
some of the tower and hardware manufacturers themselves is not as great as
we might prefer. Some of the data supplied by a popular tower
manufacturer does not withstand scrutiny. Beware of placing unquestioning
faith in the catalogues and data sheets.
--
73 de Bob, K0KR
>From Walter Deemer <ac1o@gate.net> Thu Apr 25 16:00:23 1996
From: Walter Deemer <ac1o@gate.net> (Walter Deemer)
Subject: The Ultimate Sacrifice To The RF Gods
Message-ID: <199604251500.LAA110352@osceola.gate.net>
WASHINGTON, April 25 (AP) -- For many years, it has been secretively
whispered among certain East Coast contest operators -- a very select few of
them -- that W3LPL, VERY late at night, offers the sacrifice of a maiden YL
operator to the RF Gods whenever he installs a new tower.
This myth, of course, is completely unconfirmed. It is interesting to note,
however, that in recent years there is no instance of a maiden YL operator
renewing her membership in the Potomac Valley Radio Club for a second year.
-- 73 de Walt, AC1O/4 (AP): "AC1O Press"
>From Pete Smith <n4zr@contesting.com> Thu Apr 25 16:06:42 1996
From: Pete Smith <n4zr@contesting.com> (Pete Smith)
Subject: Power, XMatch, and 72 ohm twn lead
Message-ID: <199604251506.IAA11843@dfw-ix12.ix.netcom.com>
At 01:24 PM 4/24/96 -1000, Jim Reid wrote:
>Appears this set up will be very helpful to this mid-pistol
>contest station with a Mosley tribander(hurricane country)
>and all wire antennas from 160 thru 30 meters. All four dipoles
>are fed in parallel by the single set up described. The 72 ohm
>twin line is soldered directly to the set of four dipole wires
>at the center insulator; no balun or matching up there. SWR at
>resonance is 1.2 or so on all four bands with the tuner switched
>out of the path, so realizing very little Z mismatch among the
>system elements at fo.
>
>Hope this info will be of interest to others using wires and
>wanting to use full power for contesting across all the
>low bands.
>
>73, Jim, AH6NB
>
Jim et al -- I had similarly good experience at my old townhouse QTH with an
approximately-square 80-meter full-wave vertical loop fed at a lower corner
with 450-ohm open wire line, to a 4:1 balun and thence thru RG8X to the
tuner on my TS-930. To my surprise, given its fairly limited range, the
built-in tuner successfully matched the loop on all bands 80-10 meters.
73,
Pete Smith N4ZR (n4zr@ix.netcom.com)
>From k5na@bga.com (Richard L. King) Thu Apr 25 16:10:16 1996
From: k5na@bga.com (Richard L. King) (Richard L. King)
Subject: Sacrifice to RF Gods - (Chicken & Egg)
Message-ID: <199604251510.KAA08540@zoom.bga.com>
>Richard, K5NA, suggested placing JT1 and YA cards at the bottom of your
>first tower. My question is, before you erected that 35 foot first tower,
>where did you get the JT1 qsl card? Was it from a qsl sample pack or what???
I was licensed for over 11 years before I put up my first tower. I used long
wires, dipoles, and yagis balanced on push-up masts. The first tower got a
JT1 card that was made out to K5PLF (I was K5PFL) thrown into the bottom of
the hole.
That tower worked so well that I was willing to sacrifice the YA card at the
bottom of the second tower hole. Actually I had two of the YA cards since I
had gotten one by the bureau and the other direct. Either way, G0RF seemed
to be appeased.
>This sure sounds like: what comes first, the chicken (qsl card) or the
>egg (tower).
So the Chicken still comes first and a sacrifice is a sacriface.
73, Richard - K5NA (Digging through 30,000 DX QSLs for potential sacrifice
choices for 5+ towers to go up in Texas.)
K5NA@BGA.COM
>From Jim Hollenback" <jholly@hposl62.cup.hp.com Thu Apr 25 16:51:14 1996
From: Jim Hollenback" <jholly@hposl62.cup.hp.com (Jim Hollenback)
Subject: CQP mailing
Message-ID: <9604250851.ZM22277@hpwsmjh1.cup.hp.com>
I had planned on putting together the mailing this weekend for the
CQP stuff. Unfortunately I had not printed the mailing labels and
some other lists. Last week some "friends" dropped by while I was
at work and "borrowed" my computer and my son's computer. I need to
put together a computer and do some data recovery and I should be
ready to start shipping in another 2 to 3 weeks. This pesky day job
and the evening class seem to take an awful lot of my time. Sorry
for the delay.
73, Jim, WA6SDM
jholly@cup.hp.com
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