[TowerTalk] Radial length

K4SAV RadioIR at charter.net
Sat Mar 15 19:38:52 EDT 2008


Bill Turner wrote:

>ORIGINAL MESSAGE:
>
>On Sat, 15 Mar 2008 14:43:18 -0500, K4SAV <RadioIR at charter.net> wrote:
>
>  
>
>>It is interesting to compare Cebik's calculations for gain versus number 
>>of radials with that which W8JI measured.  Cebik calculated that the 
>>gain difference between 4 radials and 64 radials was 1.2 dB.  W8JI 
>>measured 5.5 dB difference between 4 and 60 radials. 
>>    
>>
>
>------------ REPLY FOLLOWS ------------
>
>The difference is no doubt due to differences in ground conductivity. If
>you live over highly conductive ground, the number of radials would have
>less impact. Over poor ground, the more radials, the less loss.
>
>73, Bill W6WRT
>
>  
>
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Poor ground does make the difference larger, but to account for a gain 
difference of 5.5 dB in NEC, the ground quality at W8JI would have to be 
poorer that that in downtown New York City in the middle of the high 
rise buildings.   If it was only just very poor, or equal to that of a 
typical city, the gain difference would have only been 2.3 dB as 
calculated by NEC.  W8JI's ground may not be as good as some of the 
mid-western states, but it is no where near that of the downtown area of 
a city.

Jerry, K4SAV


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