[TowerTalk] Practical Grounding at reasonable cost.

[Roger (K8RI) on TT]

The Thread "RF Grounding is a myth" has a lot of useful information as 
well as good information, but useless for hams in general.

  A "Franklin System" is lightening rods connected to grounds!  They can 
be elaborate or simple.  Usually to ground rods and often to a perimeter 
ground with ground rods every 20 feet when using 10' rods, not just at 
the corners.  These are widely used in industry.  You will see them on 
the top corners and peaks of buildings and towers in chemical plants.  
Our barn had such a system and it was built decades before I was born.  
Somewhere I have some photos of "the Barn Raising".  The only source of 
power, other than "man power" are the teams of work horses visible.

The UFER is probably the largest, effective ground most hams can 
afford.  Tying the rerod together in the tower foundation and tying it 
to the station ground would likely give a more efficient and effective 
ground than most stations have.  Remember, no leads should penetrate the 
concrete below grade. Through conduit is normally an exception.  Large 
copper grounds that leach are again are effective, but impractical for 
most hams.

It should be noted that the concrete in grounds also leaches ions into 
the surrounding soil, slowly increasing its conductivity. (see Wikipedia 
on UFER grounds)  A few ground rods encased in concrete would likely 
increase the efficiency far beyond the practicality of more ground 
rods.  The ones I have seen  are formed by using a large cardboard tube 
as a form to cast the ground rod in concrete. (remove the form before 
planting the ground!) An auger digs a hole of the proper diameter to the 
proper depth and the encased rod is lowered into place. Not cheap, but 
very effective. Not all that expensive when compared to the number of 
rods and cable they replace.

  I'm half tempted to replace my ground system with a UFER ground and a 
half dozen encased 10' ground rods on a perimeter ground. Still, I can 
not get under the 30 foot wide garage apron.  At $3.00 a pound for scrap 
copper, that's more than what I paid for that cable when it was new. 
<:-))   Impractical to dig up the current system? Yup, but it's still 
tempting.<LOL>

The perimeter ground is good, but pricey.  In general, I'd say ground 
rods longer than the NEC required 10' are not going to gain much, if 
anything, and driving even 10 footers can be problematic let alone, 
longer rods...

Remember: These ground systems are for safety. They have nothing to do 
with RF, or how good your antennas work.

-- 

73

Roger (K8RI)


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