[SBE] conversation topic: how often do you check tower ground wires?

[A9xw at cs.com]

Good answer. I did an AM array for a DA 2 as part of an ownership change.  
The previous owner had removed the daytime tower ground radials (#2 &#3) and put 
them on the night time towers (#3, &#4).  Tower 1 was common to both 
patterns. The RF field strength was a fraction of the value expected when a radial 
check was made. Basically the RF was going into space and little on the ground. 

Although the original question was how often do you check it, you made some 
good points about ground rods and radials. I have seen some AM stations where 
the radials were just staked on top of the rocks no soil present, and others 
where barb wire or other non copper wire was used.  I am sure we have all seen 
the NAB Engineering Handbook for strap where radials meet, and ground strap for 
RF, as well as ground strap for lightning.  Our 1,008' tower has 8 ground 
cables (single 0) plus ground strap on all coax at the tower base and at the 
building entrance. The EM build up on the 110' between the two can put several 
thousand volts between tower and building.  We also have ground rods at the 
service entrance with strap from the hardware inside. Even with this we can get 
pulses on cables inside the room enough to disturb the remote control system.  
Without the coax straps at the building you could see lots of St Elmo's fire 
dance around the room. The guys all have ground rods as well. 

One problem with ground rods is you can have a build up around each rod that 
acts as an insulator from repeated strikes. Some articles suggest an acid 
earth treatment to improve the ground rods contact.  I've also seen glass trails 
from ground rods in sandy conditions. 

The question remains, how often do you check the ground system (radials or 
rods)?

Henry