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RF GROUND

The following instructions are almost identical to a new RF 
ground that I installed at my new house site. I was fortunate
enough to have access to a foundation sump in a corner, right
in the same area where I intend to fire my coils. I will bond
this ground to the other grounding straps and pipes around the 
property in an effort to obtain the highest-Q ground possible.

Using surplus or scrap material for the large pipe section (or
like me, the foundation sump) the rest of the ground system 
should run about $30.00 usd.

This is one of the easiest, cheapest, and most effective RF grounding
techniques for Tesla coilers. This ground is not cost effective for use 
24-7, but when used occasionally (daily for a few hours) for RF ground-
ing tank circuits and secondary coils you will get a lot of "bang for 
the buck". This ground also improves over time.

It is best to select a low spot or natural drainage area that is as 
close as possible to the base of the Tesla coil. Try to get the inital
placement within 15 - 20 feet of the Tesla lab. You will need the 
following materials:
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TWO, 8 FOOT COPPER CLAD STEEL GROUND RODS, 
or
TWO, 8 FOOT LONG BY 3/4 INCH DIAM. HARD COPPER WATER PIPES  
or
ONE, 8 FOOT LONG BY TWO INCH DIAMETER GALVINIZED STEEL PIPE
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TWO HUNDRED POUNDS OF ROCK SALT OR WATER SOFTENER SALT
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ONE HUNDRED POUNDS OF COARSE SAND AND A FEW BUCKETS OF GRAVEL
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A FOUR FOOT LENGTH OF VERY LARGE DIAMETER PIPE (10 INCHES DIAM. MIN)
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ONE ROLL OF FOUR INCH or SIX INCH WIDE ALUMINUM STRAP (gutter flashing)
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ELECTRICAL OXIDE INHIBITOR
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HOSE OR OTHER CLAMPS FOR THE ROD OR TUBE CONDUCTORS 
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DIGGING AND TRENCHING TOOLS
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Start by digging a hole at least four feet deep that will accept the 
large diameter pipe. It is advisable that a two foot or three foot 
diameter pipe be used. PVC, corrugated culvert, concrete, iron, 
really any type of pipe may be used depending on what is available.

Once the hole is dug, case or line the hole with the pipe, then fill 
with water. Do not allow too much of the casing pipe to remain above
ground level, a few inches is OK. Next, work (or drive) the rod (or 
tube) conductor(s) into the earth at the bottom of the cased and water 
filled hole. It is important that as much conductive rod or tube as 
possible be in contact with the earth. Place the vertical conductors
near the edge of the cased hole. If two vertical conductors are used 
then place them on opposite sides of the hole.

Once the vertical conductors are in place, trench a path back to the 
Tesla work area. Make the trench wide enough to accept the four inch
or six inch smooth alumium strap (gutter flashing). Make sure the 
trench is below the sod level. 

Smear the top(s) of the vertical conductors with a light coat of
electrical oxide inhibitor. This compound is used to prevent 
corrosion whenever electrical connections between disimilar metals 
are made. Once smeared with inhibitor, wrap one end of the aluminum 
strap around the vertical conductor and clamp into place with a hose
(or other) clamp. Verify the connection with a VOM. If two verticals 
are used then use two separate lengths of aluminum strap. Place the 
strap into the prepared trench back to the Tesla work area and back-
fill the area in.

Next pour a few inches of gravel into the bottom of the cased ground
hole. Begin to backfill the cased hole by alternating shovels of salt
with half shovels of sand and gravel. Continue until the hole is filled.

The ground is left dry when not in use. Before firing coils, fill the 
ground hole with water. The water will dissolve the salt which then 
migrates downward to form a conductive "plume" in the subsoil. The salt 
will require periodic replenishment. Over time, and with continued use,
the salt plume will make contact with bedrock or the water table. 

The vertical conductors will corrode fairly quickly in the presence of
the moist salt. After a few years new vertical conductors should be 
driven in and connected alongside the old ones. The alumium strap that
is used to make the run between the lab and the ground pipe will also
corrode and will need to be renewed after a few years.

Improvements to this ground may be made by substituting copper strap
for aluminum strap in the construction. Copper will last longer and 
will make a better connection to the verticals. Another improvement 
can be made by clamping a conductive mesh screening to the vertical 
conductor in the cased ground hole. This will allow a greater surface 
area of contact with the salt water. The best mesh is either copper, 
steel or stainless steel harware cloth. Do not use aluminum screening.

The purpose of the sand and gravel is to prevent caking of the salt
which will prevent water from passing through the ground hole. When 
the salt is replenished it is a good idea to remove some of the sand
amd gravel or otherwise mix the sand and salt together. Dumping in
a large quantity of salt all at once without some inert filler will
cause a salt block to form that is difficult to break up or dissolve.

The theory of operation is pretty simple. The casing pipe prevents 
the salt from migrating sideways in the surface soil where grass, 
bushes, and tree roots would be poisoned. The salt dissolves and
travels downwards into the moist subsoil, while at the same time
spreading out laterally. When the "plume" contacts the water table
a connection is made. If the soil is very dry and shallow the plume 
will desend to the bedrock and will then expand laterally which forms
an underground plane. In either case the ground that is formed is
high quality when wet, and is ideal for even very high powered Tesla 
coiling without modifications.

Richard Quick

... If all else fails... Throw another megavolt across it!
___ Blue Wave/QWK v2.12