I've found that the best source of information about grounding is the National Electrical Code (NEC). That includes antenna grounding and the 'how' of doing it.
How you do safety grounds depends a lot on the antenna and where it is (naturally). As already suggested, an arrestor in the feed line is a very nice thing to have. The effective ones are NOT cheap. The 'spark-gap' type are always too 'late' to provide much protection to the equipment on that feed line. All safety ground require an adequate means of dissipating current, a single ground rod is a terrible safety ground (check that NEC). The conductor used to connect to ground also needs to be capable of carrying the current to ground, which means a much larger 'wire' than commonly thought. The minimum size for those is 6 gauge or larger. The connections of that ground wire are also important. There will be lots of current, which means heat depends on just how much, and that means a good mechanical connection, not just soldering the thing (also in that NEC). And then there's the 'catch' that the length of that ground wire will be 'controlled' by the frequency of use of the antenna it's supposed to be protecting. So, electrically speaking it should be short as possible, and RF speaking it can't be particular lengths according to the frequency of use. [Getting complicated, ain't it?? It is NEVER simple.]
So would that vertical be better on the ground? Just depends on where you wanna put in the labor. Any antenna near the ground will benefit from the 'dirt' being more conductive (less ground losses). Will that ground mounted antenna beat a roof mounted one? Only if there's a lot of effort put into the ground radials used with that antenna. Or would you rather put that 'effort' in to mounting the thing on the roof? Probably the same amount of work, just in a different form. Either method will also depend on how well that antenna, in that particular location, is tuned. Which is also not exactly 'simple'.
So which is best for you? I don't have the slightest idea, and neither does anyone else here unless they have done exactly the same sort of thing in exactly the same conditions/locations/antenna. Not a very 'nice' answer huh? The nice part is that it isn't said anywhere that you only get one shot at an antenna. I know of very few people who have only had just one.
Have fun.
- 'Doc
How you do safety grounds depends a lot on the antenna and where it is (naturally). As already suggested, an arrestor in the feed line is a very nice thing to have. The effective ones are NOT cheap. The 'spark-gap' type are always too 'late' to provide much protection to the equipment on that feed line. All safety ground require an adequate means of dissipating current, a single ground rod is a terrible safety ground (check that NEC). The conductor used to connect to ground also needs to be capable of carrying the current to ground, which means a much larger 'wire' than commonly thought. The minimum size for those is 6 gauge or larger. The connections of that ground wire are also important. There will be lots of current, which means heat depends on just how much, and that means a good mechanical connection, not just soldering the thing (also in that NEC). And then there's the 'catch' that the length of that ground wire will be 'controlled' by the frequency of use of the antenna it's supposed to be protecting. So, electrically speaking it should be short as possible, and RF speaking it can't be particular lengths according to the frequency of use. [Getting complicated, ain't it?? It is NEVER simple.]
So would that vertical be better on the ground? Just depends on where you wanna put in the labor. Any antenna near the ground will benefit from the 'dirt' being more conductive (less ground losses). Will that ground mounted antenna beat a roof mounted one? Only if there's a lot of effort put into the ground radials used with that antenna. Or would you rather put that 'effort' in to mounting the thing on the roof? Probably the same amount of work, just in a different form. Either method will also depend on how well that antenna, in that particular location, is tuned. Which is also not exactly 'simple'.
So which is best for you? I don't have the slightest idea, and neither does anyone else here unless they have done exactly the same sort of thing in exactly the same conditions/locations/antenna. Not a very 'nice' answer huh? The nice part is that it isn't said anywhere that you only get one shot at an antenna. I know of very few people who have only had just one.
Have fun.
- 'Doc
