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307
| | Posted on Friday, November 30, 2001 - 9:17 pm: | 
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Coax , Coax , Coax
It is very important to have your base station antenna either a beam or ground plane well grounded for many reasons . Lightning is one main reason and also noise in your CB from stray signals around the neighborhood can also be present without one . There are two types of grounding on antennas , one is DIRECT DC GROUND which is normally an aluminum antenna that when a ohm meter is touched from the center of the coax connector to the main radials of the antenna , you will see "0" ohms . These antennas are very safe in an electrical storm because when they get hit by lightning they will dissipate all of the current directly to ground and will handle lots of current in the process . A Maco Alpha V 5/8 ground plane is a DIRECT GROUND ANTENNA and is highly recommended for base station antennas . I have personally been hit twice and the antenna is not even welted or for that matter there are not even any marks on it . The other type of antenna is the so called DC GROUND antenna that in theory is DC ground but through a capacitor . The problem with capacitors are they will let some of the current go to ground in the event of a lightning hit but in most cases the capacitor will just blow out of the path and you have fiberglass all over your yard the next morning . Generally any fiberglass antenna (in most cases and some commercial antennas are DIRECT GROUND FIBERGLASS antennas) is a DC "coupled" ground antenna and are recommended for low level mounting (not 200 feet up on the tip top of a tower) . Grounding all the points on the tower is a good idea , you know where the pole goes into the apex ? that's a good point to run a jumper from the pole to the tower instead of depending on the one bolt that holds the pipe in the apex for the ground transfer . Another great thing to do is dig a hole about 5 feet deep , go to the local junk yard and get a large radiator and when you get it home , fill it up with salt and drop it in the hole . run a piece of number 4 or 6 cable up from the radiator to the base of the tower . I have a ground test meter and have been able to reach less than 2 ohms in reference to my main power ground . |
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