I would expect it to be.
With ground radial fields of these sorts of dimensions you are primarily
affecting the Near Field efficiency, not the elevation angle. To
substantially affect the elevation angle you need to be changing the
ground conditions in the Fresnel Zone, which extends much further out.
73,
Steve G3TXQ
On 15/01/2011 17:18, Gene Fuller wrote:
> Is the loss equal for all vertical radiation angles ?
>
>
> ----- Original Message -----
> From: "Steve Hunt"<steve@karinya.net>
> To:<towertalk@contesting.com>
> Cc:<towertalk@contesting.com>
> Sent: Friday, January 14, 2011 4:54 PM
> Subject: Re: [TowerTalk] Fw: ground radial project
>
>
>> Jim,
>>
>> Agreed!
>>
>> If folk would look carefully at the Brown/Lewis/Epstein paper they would
>> see that it's not so different from Rudy Severn's work. Figure 30 in
>> their paper plots received field strength against number of radials for
>> a quarter-wave vertical radiator. Compared with the theoretical maximum,
>> these are the shortfalls they measured:
>>
>> 15 radials: -2dB
>> 30 radials: -1.3dB
>> 60 radials: -0.7dB
>> 113 radials: -0.2dB
>>
>> To me that doesn't look like a strong case for 120 radials in Amateur
>> Radio useage!
>>
>> 73,
>> Steve G3TXQ
>>
>> On 14/01/2011 21:26, jimlux wrote:
>>> That 120 radial thing is from Brown, Lewis and Epstein, and was
>>> originally formulated as a FCC shortcut to avoid having to do a proof of
>>> performance on a non-directional AM transmitter (i.e. rather than spend
>>> the money to measure field strength on all the cardinal radials and so
>>> forth, you could say, we've installed the FCC standard ground field).
>> _______________________________________________
>>
>>
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