[TowerTalk] Re: One more ground radial question

[Jan Erik Holm]

Understand. However in this case we are not trying
to confirm loobes in the vertical plane. We are trying
to improve the near field to get less R-loss, that we
can confirm and measure without using helicopters.
Lets stick to the original issue.

73 Jim SM2EKM
-----------------------------------------------

Jim Lux wrote:
> At 05:09 PM 12/18/2003 +0100, Jan Erik Holm wrote:
> 
>> You need no helicopter. In practical sense just
>> measure the ground wave.
>> We are not trying to confirm loobes in the vertcal
>> plane, then you need helicopters.
>>
>> 73 Jim SM2EKM
> 
> 
> 
> But, for HF skywave communications, you ARE very concerned about the 
> skywave.  The near and midfield (say, out to 10-20 wavelengths) will 
> have a huge effect on what the pattern looks like close to the ground, 
> or, at least up to 20-30 degrees, which is usually what folks are 
> worried about.
> 
> It would be very, very difficult to relate, with any confidence, the 
> measurements you might make at ground level to the gain at 5,10, or 20 
> degrees above the horizon. (unless you're like Rick Karlquist, with an 
> antenna out Galt,CA in the middle of a flatter than Kansas plain with 
> fairly uniform soil characteristics for miles in every direction)
> 
> A very small change in the soil characteristics radically changes the 
> depth of the "null" at the horizon for horizontally polarized antennas 
> over ground. Less of an effect for the vertically polarized antennas. 
> Since almost all practical antenna systems radiate both polarizations, 
> and the skywave itself is fairly randomly polarized, such things are 
> important.
> 
> 
> 
> 
> 
> 
> 
>> ---------------------
>>
>> Jim Lux wrote:
>>
>>> Hard to do, in a practical sense... You'd need a measurement receiver 
>>> in an
>>> airplane, helicopter, balloon etc, because the field strength at "ground
>>> level" isn't really what you're interested.
>>> Perhaps measuring beacons before and after?  But you've got the 
>>> propagation
>>> variations to worry about.
>>> This is why evaluating HF antennas is such a royal pain.
>>> ----- Original Message -----
>>> From: "Jan Erik Holm" <sm2ekm at telia.com>
>>> To: <towertalk at contesting.com>
>>> Sent: Wednesday, December 17, 2003 8:37 PM
>>> Subject: [TowerTalk] Re: One more ground radial question
>>>
>>>
>>>> Is something like this ever confirmed by field
>>>> strenght measurements?
>>>>
>>>> 73 Jim SM2EKM
>>>> --------------------------------------------------
>>>>
>>>> Don Havlicek wrote:
>>>>
>>>>> Yes!
>>>>> In my case ... 60 radials spaced 6 degrees apart .. then 
>>>>> concentrations
>>>>> of ten radials at 1 degree each for Europe, Japan, South America, and
>>>>> VK/ZL ... works like gangbusters .. all I need now is to clean out the
>>>>> shack and put a new feedline out to the vertical again!
>>>>> Don
>>>>> N8DE
>>>>>
>>>>> va3pl at cuic.ca wrote:
>>>>>
>>>>>
>>>>>> ----- Original Message ----- From: "Don Havlicek" <n8de at thepoint.net>
>>>>>> To: <kb9cry at comcast.net>
>>>>>> Cc: <TowerTalk at contesting.com>
>>>>>> Sent: Wednesday, December 17, 2003 12:12 PM
>>>>>> Subject: Re: [TowerTalk] One more ground radial question
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>> I believe the word "optimum" should be replaced with "sufficient".
>>>>>>> My experience with verticals tells me that 100 radials works much
>>>>>>> better than 60, especially when concentrated in certain directions.
>>>>
>>>> ,
>>>>
>>>>
>>>> _______________________________________________
>>>>
>>>> See: http://www.mscomputer.com  for "Self Supporting Towers", "Wireless
>>>
>>> Weather Stations", and lot's more.  Call Toll Free, 1-800-333-9041 
>>> with any
>>> questions and ask for Sherman, W2FLA.
>>>
>>>> _______________________________________________
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>>>> http://lists.contesting.com/mailman/listinfo/towertalk
>>>
>>>
>>
>>
>> _______________________________________________
>>
>> See: http://www.mscomputer.com  for "Self Supporting Towers", 
>> "Wireless Weather Stations", and lot's more.  Call Toll Free, 
>> 1-800-333-9041 with any questions and ask for Sherman, W2FLA.
>>
>> _______________________________________________
>> TowerTalk mailing list
>> TowerTalk at contesting.com
>> http://lists.contesting.com/mailman/listinfo/towertalk
> 
> 
> _______________________________________________
> 
> See: http://www.mscomputer.com  for "Self Supporting Towers", "Wireless 
> Weather Stations", and lot's more.  Call Toll Free, 1-800-333-9041 with 
> any questions and ask for Sherman, W2FLA.
> 
> _______________________________________________
> TowerTalk mailing list
> TowerTalk at contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
>