I know this has been tackled many times so I will try to be brief. I am a fire Chief for a semi-rural FD. We operate on a 100w Motorola moto turbo vhf repeater system. After having some crippling issues with noise discovered and repaired on our system (loose heliax connector) I have taken a special interest into how our station is grounded. and before I continue, yes there is still a small amount of noise on our system.
Currently all110v a/c is grounded per code except for that ground rod only being driven down about 6’. There is another exterior ground rod (very corroded and old) driven on the opposite end (radio install end of the shack). This ground has antenna shielding for the other vhf/uhf connected at the rod then a #2 copper wire running into the shack where the chassis ground for our radio’s single point ground and duplexer ground are tied into, as well as the chassis grounds for the other vhf and uhf radios that we share the shack and 120’ antenna mast with. The lightening arrester for our duplexed antenna coax is also bonded to this ground... it should be noted that this ground system is not tied to the shack’s main a/c ground.
Then the steel 120’ antenna mast is also seemingly grounded at all 3 points where bolted to the cement base. I say seemingly because I found the copper ground wire from one leg only going into the ground about a foot and not mechanically connected to a rod. This third ground system is also not tied to either of the other 2 ground systems - a/c ground and radio chassis grounds.
I know I should drive the shallow a/c ground down all of the way, replace the radio chassis ground rod with a properly installed rod, and also make sure the antenna mast ground is also properly grounded with a new rod. But are any-or all of these separate grounds supposed to be tied together? Is It ok for the chassis grounds to be separate from the a/c power ground?
I know about the NEC and Motorola’s document but I wanted to get your opinion on my questions posed above.
Currently all110v a/c is grounded per code except for that ground rod only being driven down about 6’. There is another exterior ground rod (very corroded and old) driven on the opposite end (radio install end of the shack). This ground has antenna shielding for the other vhf/uhf connected at the rod then a #2 copper wire running into the shack where the chassis ground for our radio’s single point ground and duplexer ground are tied into, as well as the chassis grounds for the other vhf and uhf radios that we share the shack and 120’ antenna mast with. The lightening arrester for our duplexed antenna coax is also bonded to this ground... it should be noted that this ground system is not tied to the shack’s main a/c ground.
Then the steel 120’ antenna mast is also seemingly grounded at all 3 points where bolted to the cement base. I say seemingly because I found the copper ground wire from one leg only going into the ground about a foot and not mechanically connected to a rod. This third ground system is also not tied to either of the other 2 ground systems - a/c ground and radio chassis grounds.
I know I should drive the shallow a/c ground down all of the way, replace the radio chassis ground rod with a properly installed rod, and also make sure the antenna mast ground is also properly grounded with a new rod. But are any-or all of these separate grounds supposed to be tied together? Is It ok for the chassis grounds to be separate from the a/c power ground?
I know about the NEC and Motorola’s document but I wanted to get your opinion on my questions posed above.