TopBand: Radial current

[w8jitom@postoffice.worldnet.att.net]

Hi Ward,

> For example, assume ground is reasonably uniform under the radials.  So
> current imbalance is primarily due to differences in length or arrangement
> of the radials.  Thus, changing the length of the radials would not
> greatly affect the loss due to ground-related effects, but would strongly
> affect current balance. 

If I understand correctly, you wonder what would happen if 
earth effects were uniform, and the current unbalance was due to 
length or placement of the radials.

Let's look at the case of two radials side by side. If the radials 
couple to each other nearly as tight, or perhaps a bit tighter, than 
they couple to their surroundings, and one radial off in another 
direction that has little mutual coupling to the other two radials.

In that case the current would divide between the two close spaced 
radials, but the coupling effects to the surroundings would be nearly 
the same as if they were one wire. (A folded dipole would be an 
extreme example, the net radiation is the radiation caused by the 
sum of currents in each wire.)

In this example, if currents were made equal, unwanted far field 
radiation would INCREASE. The two closely coupled radials would 
radiate more than the single radial opposite them. 

Once again equal currents wouldn't indicate the least 
unwanted radiation or loss.


73, Tom W8JI 

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