[TowerTalk] Screw Anchor Experience

[K0DAN]

SEE CAPS BELOW

-----Original Message----- 
From: Randy
Sent: June 18, 2013 20:44
To: K0DAN
Subject: Re: [TowerTalk] Screw Anchor Experience

Wow. I wonder what the source of the corrosion/electrolysis actually was?

DISSIMILAR METALS IS THE BASIC ANSWER; THE CHEMISTRY IS MORE COMPLEX, BUT 
THE FURTHER APART MATERIALS ARE ON THE ATOMIC TABLE, THE MORE THERE WILL BE 
GALVANIC ACTION. SOME INSTALLATIONS RECOMMEND SACRIFICIAL ANODES, OTHERS 
ELEVATED PIERS, ETC. MOST OF THESE ARE EITHER BEYOND THE BUDGET OF MOST HAM 
APPLICATIONS, AND/OR ARE BEYOND THE GENERAL KNOWLEDGE & FOLKLORE OF HAM 
INSTALLATIONS. ALSO, STATISTICALLY SPEAKING, MOST TOWERS DON'T COME DOWN 
(DUE TO LUCK, THE HAND OF GOD, ETC.).

There are millions and millions of utility poles guyed with these
things...and methinks
that they aren't isolated from the grid, but tied into the
neutral/ground, am I right?

YOU ARE RIGHT ABOUT THERE BEING PLENTY OF UTILITY ANCHORS. I DON'T KNOW IF 
THEY'RE TIED TO NEUTRALS. I WOULD SUSPECT THEY HAVE THEIR OWN SEPARATE 
GROUNDS, WHICH MAY OR MAY NOT BE TIED TO NEUTRALS (MOST POWER UTILITY 
SERVICE IS 3 PHASE @ 440VAC AND UP...THAT CRAFT IS BEYOND ME). I ALSO 
SUSPECT THE UTILITIES INSPECT/REPAIR/REPLACE ON FAR MORE REGULAR INTERVALS 
THAN HAMS. ALSO, THEY HAVE LOTS OF REDUNDANCY ON THEIR POLES...IF ONE GOES 
DOWN IT IS HELD UP BY THE OTHERS AND EVENTUALLY FIXED. KIND OF APPLES & 
ORANGES WHEN COMPARED TO YOUR TYPICAL HAM INSTALLATION.

I do know that, on occasion, the ground/neutral coming off the pole is
not at exactly "ground"
potential. People familiar with boats know that sacrificial zinc anodes
are often attached to boats
to prevent other metal parts from eroding due to electrolysis, since
zinc is lower down on the
electrolysis totem pole than other metals...

EXACTLY. I HAVE NO EXPERTISE HERE, BUT KNOW THE CONCEPT. IN MY EXPERIENCE, 
THIS TYPE OF CRAFT IS BEYOND THE TYPICAL HAM INSTALLATION AND IS RARELY OR 
NEVER SEEN IN THE DOCUMENTATION PROVIDED BY TOWER MANUFACTURERS, AND 
CERTAINLY NOT PROVIDED BY HAM DEALERS WHO WANT TO MOVE MERCHANDISE AND DON'T 
KNOW OR CARE ABOUT THE INSTALLATION THEREOF. ALSO, MY CRASHED TOWER WAS UP 
15+ YEARS AND CAME DOWN AROUND 1998. I WISH IT WAS STILL IN PLACE, BUT AT 
WHAT POINT TO TOWER MANUFACTURERS, DEALERS, AND BUYERS CONSIDER A STRUCTURE 
TO BE AT END OF LIFE CYCLE? I THINK WHEN MOST HAMS INSTALL A TOWER, THEY 
EXPECT IT TO BE THERE "FOREVER" (GOOD LUCK). I'M NOT BEING SNARKY...I 
EXPECTED MINE TO BE THERE "FOREVER", BUT I WAS MISTAKEN. I COULD HAVE ADDED 
MORE LABOR/MATERIALS TO EXTEND THE LIFE CYCLE BUT I DID NOT KNOW ANY BETTER.

I once pulled up a 1/2" copper water pipe ground "rod" used on an
aluminum tower that was
mounted on galvanized pipe in the concrete base, and it was *shiny* and
noticeably thinner
on the part that had been buried. I removed the screw anchors went I
took it down but didn't
look for or notice any missing galvanizing (which we all know is zinc).
Or maybe stray voltage from one of the rigs went up the coax shield and
down the guy wire to
cause electrolysis in your case...?

WHO KNOWS? I HAVE PULLED SO-CALLED COPPER GROUND RODS (WHICH ARE COPPER 
PLATED STEEL) OUT OF THE GROUND AND THEY LOOKED NOTHING LIKE COPPER, NOT 
EVEN LIKE CORRODED STEEL! NEVER MEASURED THEIR RESISTANCE BUT PROBABLY 100'S 
OF OHMS! CERTAINLY NOT "GROUNDS" AS WE EXPECT THEM TO BE. DITTO ON CLAMPS 
AND WIRE WHICH ARE NOT OF THE SAME MATERIAL.

Really a head-scratcher...

THE CHEMISTS AND ELECTRICIANS PROBABLY HAVE A LOT OF ANECDOTAL EVIDENCE TO 
ADD.

BTW SORRY FOR THE CAPS BUT WANTED MY THREAD TO BE SEPARATE FROM YOURS.

73
Randy
KZ4RV

GL ES 73
DAN
K0DAN

On 6/18/2013 8:19 PM, K0DAN wrote:
> Hi Shawn...
>
> I had screw anchors which I think I purchased from Texas Tower. They were 
> probably manufactured by Rohn or some other well-known tower mfgr.
>
> IRC they were 4” augers on 4’ 3/4” (or 1”?) rod, all galvanized. They met 
> the tower mfgr (TriEx) spec. They were installed (with difficulty) into 
> local soil here near Kansas City. Which is about 2’ of topsoil on top of 
> packed clay. I do not know the pH of the soil.
>
>


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