Topband: Supplemental ground rod installation for existing 160m tower

[Jeff Blaine]

I have a full size vertical built from 25G running against about 80 1/4 
WL radials - #18 insulated wire sewn into the ground an inch or two 
below ground.  There is a single ground rod next to the base but no 
other ground rods on this tower.

We had a lot of lightning here last week and the tower took a hit which 
popped a wire off the matching net.  I am going to put a spark gap of 
some sort on that tower to help address that but it's got me wondering 
if I should also add in a set of ground rod.

The other towers on the site have extensive ground rod structures.  The 
nearest tower to the 160m, for example, has 27 rods mounted along 9 bus 
runs.

If rods are needed, does the existing ground radial screen offer me a 
discount on what is needed?    I'm assuming that the existing radial 
field would provide some level of ground coupling for lightning and to 
get an equivalent level compared to the other tower.  Meaning somewhat 
less than 27 rods - when combined with the existing 80 1/4WL radial 
field - would be functionally the same as the other tower has.

73/jeff/ac0c
alpha-charlie-zero-charlie
www.ac0c.com