In a message dated 96-04-26 16:59:51 EDT, you write:
>So it looks like what needs to be done is a calibration chart needs to be
>made by someone who has an accurate dynomometer, a Loos tension guage, and a
>few towers with various types and sizes of guy wire.
I was going to do a big calibration routine and post it to the list... but
after using mine to equalize the philly guys on my tower, I lost all
interest, as it is not necessary... I tightened my guys to just over 400#
indicated - to allow for the extra stiffness of EHS - and the guys are
absolutely perfect to my eye, and twanging, etc...
If you must calibrate it... Suspend a sling with a piece of the cable to be
calibrated and load cement bags onto it until you are at the poundage you
desire...Then calibrate the Loos guage against your known load...
Denny
>From John Brosnahan <broz@csn.net> Sat Apr 27 13:54:32 1996
From: John Brosnahan <broz@csn.net> (John Brosnahan)
Subject: Cro-magnon Man Forces Rod In
Message-ID: <199604271254.GAA28898@lynx.csn.net>
This note provides some additional comments in regards to Jim's
(K1ZX) posting. I am not picking on Jim--I like him--he
laughs at my private email jokes! But I wanted to fill in
some details to help provide the entire picture.
73 John W0UN
>Several years ago in the No Cal DXer I saw where a W6 recommended using 1/2"
>copper water pipe with a heart of #4 reinforcing steel (that's 1/2") as an
>economical ground rod.
I was never completely comfortable with this technique since it
left the steel core inside the copper and essentially doubled
the cost of the total ground rod. The roughness of the rebar
made it very difficult for the rebar to be removed after the
driving exercise. And it left a steel copper interface that could
allow water between the two which would probably result in
galvanic action inside the ground rod.
>Plumbing stuff always has a call size which relates to its inner diameter
>(after all that is where the water travels)...so 1/2" plumbing tubing is 1/2"
>on the inside. This is akin to when you need a mast and the guys asks you if
>you want a pipe or a tube - see W6QHS' book.
Just don't use water pipe for a mast--it is not specified for
structural use and can be pretty wimpy.
>Some of this imported stuff is not as good as the others as far as
>tolerances. Sometimes a sloppy mold will result in the bar being unable to
>slip into the tubing.
I have found a lot of variation in rebar OD depending on the stamping
pattern used by the particular mill, making it somewhat problematic
to find #4 rebar that will actually fit.
>To drive these things into the hard clay over here in Tampa we use the ideal
>weapon....a demolition hammer, with a ground rod driving tip. Yes, they are
>made! The tool looks kind of like something Arnold Schwartzenager used in the
>Terminator. This is an expensive tool, so we use it a lot to reduce the
>average cost per usage.
These tools are slick, but I have had problems when using them in the
winter--just when you most need a boost to drive things through the
frozen ground. They seemed to freeze up and would work inside
in 40-50 degrees but not outside at 20 degrees or less. Something
the Florida gang would not know about!
I installed about a 100 T-fence posts in the middle of winter for a series
of Beverages. Driving them with a post driver required about 10 times as
many "whacks" as is needed when the ground isn't frozen. The
effort went from about 10 "whacks" normally to about 100 "whacks".
Bad enough that I had to take a break and complete the job on the
second day. 10,000 whacks total was more than my arms could
handle at one time.
>This tool is really slick, the machine beats the living **** out of the rebar
>and of course its small opposite end is more than glad to drive into the
>earth when its rear end is being hammered! The trick is in starting a 10 ft
>long rod vertically whilst holding a very heavy three foot long jackhammer
>atop it.
The guys who use these tools to set road sign post (which are square
tubing) have a special head that fits down inside the tubing. The hammer
hangs from a boom on a cable so that it can be swung out over the
post from the back of the pickup and lowered onto the tubing. A little
more elaborate than what can be justified for a small number of
ground rods.
The one other disadvantage of the power method, either pneumatic
or electrical is that you need a source of power at the site--which
may be a long way away if you are driving grounds at the far ends
of your Beverages.
>I gather from the wet it with a hose gang that this is backwards and
>cro-magnon like....but it is also a very manly thing and makes you feel like
>grabbing a cold brewsky after you drive one home.
And the cost savings will allow you to buy many a cold one, but like
all antenna work, wait until the job is over before imbibing.
>In order to do this properly I recommend you have a sweat stained torn
>t-shirt, and a pair of pants which are slightly too small for you - and that
>those pants ride a lil' too low....ooops - just say no to crack!
Us Scotch/Irish types usually wear kilts when performing this
procedure which is why I don't want to be up on a step ladder
with a lot of kibbitzers hanging around! So I normally work alone.
73 John W0UN
John Brosnahan
La Salle Research Corp 24115 WCR 40 La Salle, CO 80645 USA
voice 970-284-6602 fax 970-284-0979 email broz@csn.net
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