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Re: [TowerTalk] ground rod depth problem due to rocky soil -- solutions?

 To: Jim Lux Re: [TowerTalk] ground rod depth problem due to rocky soil -- solutions? Michael Goins Fri, 16 Nov 2012 11:42:12 -0600 mailto:towertalk@contesting.com>
 ```Agreed, but for most people, connect/disconnect is by far the easiest way to go if it's not overly inconvenient. For a contest multi-station, absolutely stay connected because of the level of hassle otherwise. But for joe semi-average ham, a clean break is simple and works 100% of the time (assuming you do it each time, which I do). Keeps lightning out of the house/station instead of trying to do something with it when it arrives. Michael Goins, K5WMG Professor, Writing University of Texas at San Antonio * * On Fri, Nov 16, 2012 at 11:17 AM, Jim Lux wrote: > On 11/16/12 7:46 AM, K1TTT wrote: > >> My program doesn't do strap, so instead of 2" strap that the OP has, I >> substituted 1" wire which gives a slightly smaller surface area... the OP >> said he was going have 700' of buried stuff so that is what I used... of >> course you can't bury in rock, but I can simulate it as a worst case, the >> 1' >> of topsoil on top shows there isn't much difference. >> >> > From a transient behavior standpoint, I would imagine that the wire could > be insulated it and would work about the same. 700 feet x 1/3 foot is > around 230 square feet of surface area, or 22 square meters.. > > if it's separated by 1mm from the "earth", that's a capacitance of > 8.85E-12* 22/1E-3 F or about .2 uF... > > At a nominal 1 MHz (for lightning), that's an impedance of a bit less than > an ohm... > > > and, because I'm a fan of Ufer grounds.. a 3x3x3 foot cube of concrete in > soil with the top surface exposed has a surface area of 45 square feet, so > its capacitive impedance is about 4 ohms.. a 5x5x5 cube is about 2 ohms.. > so don't worry about the vapor barrier between concrete and soil. The > concrete has lower inductance than the wire radials, too.. > > > > > > ______________________________**_________________ > > > > ______________________________**_________________ > TowerTalk mailing list > TowerTalk@contesting.com > http://lists.contesting.com/**mailman/listinfo/towertalk > _______________________________________________ _______________________________________________ TowerTalk mailing list TowerTalk@contesting.com http://lists.contesting.com/mailman/listinfo/towertalk ```