Gary there are many factors effecting ground systems. In general concrete is fairly conductive year round but earth conductivity is highly dependent on the type of soil and its moisture content. Many a user of ground return telephone systems found out clay soil in the summer could make you sound a million miles away.
Grounding systems for the shack may need to fulfill multiple functions and those functions are often at cross purposes. The impedance of an un-terminated transmission line inverts every quarter wave so connectors to ground rods used in RF systems can be completely useless if they are more than a fraction of a quarter wave in length. Likewise the vertical connectors to earth grounds from 2nd floor shacks can become unwanted radiating parts of your antenna system. Such problems do not negate the effectiveness of such ground systems for arresting lightning. Lightning does not like to make sharp turns so in general the shortest, most direct path to earth ground, will be the best lightning ground and the further away from your shack the better. This suggests that combination of a RF ground and lightning protection grounds is really a series or combination of grounds. Quantity prevails over quality. Fortunately I live in California where lightning is the exception rather than the rule so I design a good RF ground and let it go at that. 73 Fred, AE6QL -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Gary Gregory Sent: Monday, September 10, 2012 3:31 PM To: Elecraft Subject: [Elecraft] Ground Rods *Interesting discussion locally here in VK. Is there any advantage in having the Copper ground rod surrounded by concrete over having the rod driven 6 feet straight into the earth? Hope this doesn't get too far off topic or develop into a prolonged discussion but I realised I didn't know the answer if there is one. 73 * -- *Gary* *Start the day off slow, then taper off.........* K3 #679 KPA500FT #18 KAT500FT 007 P3 #1629 ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
