[Antennaware] Radials

K9AY k9ay at k9ay.com
Mon Mar 3 15:12:09 EST 2008


I'm not sure I have a full answer to your question, but the observation of 
arcing at the ends of the radials is quite interesting. The arcing can be 
reduced, as you suggest, by staking the ends of the radials. Another 
solution is to connect all radials ends to a perimeter wire, which will 
greatly reduce the pinpoint concentrations of charge that cause arcing.

Voltages aside, as part of the antenna, the radials are too few and too 
short. They may be sufficient for your own "performance vs. labor" equation, 
but they are a long way from approximating the low-impedance conducting 
surface of an efficient RF ground. I expect that a more extensive radial 
system would not arc, e.g., a larger number of short radials will have lower 
current in each wire and proportionately lower voltages at the ends.

73, Gary

> Guess I was missing some information.  The radials are not 1/4 wave, they 
> are more like 60 feet or so and I may have misled some as they are "on" 
> the ground but that amounts to laying them out and picking them up after 
> the contest so....  actually they probably are an inch or two above the 
> actual ground being held up be grass and wet leaves.  More information if 
> it helps.
> Again TIA, es 73, de Jim KG0KP
>> What detrimental effect would there be if radials (25 or so) laying ON 
>> the ground had their ends stuck into the ground or held down by spikes or 
>> LARGE nails since this is a high voltage point?  The antenna in use was a 
>> 160 meter inverted L with about 54 ft vertical and the remainder 
>> horizontal.
>> At our clubhouse, (homebrew 4-1000 amp at 4800 volts) I came out during a 
>> cw contest and the ends of several of the radials had sparks continuous 
>> with the cw being transmitted (no problem copying whatsoever).  The 
>> ground was still partly snow covered and very wet and luckily so were the 
>> leaves that were in the spark path.  No fires were started but I started 
>> thinking about danger of someone touching the radials near the end.
>> TIA, 73, de Jim KG0KP

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