I think it would be easier to steal wire above
ground rather than in the ground?
Charles Harpole
k4vud@hotmail.com
> From: ronc@sonic.net
> To: aa4nu@ix.netcom.com; tentec@contesting.com
> Date: Sat, 16 Aug 2008 11:30:33 -0700
> Subject: Re: [TenTec] OT: Ground Radials at Tower Base
>
> With all due respect to W8JI and ON4UN, there has been a lot of more recent
> research done by commercial AM broadcasters over the past couple of years
> regarding elevated radial systems for vertical radiators, especially in
> light of recent copper thefts of traditional buried 120 radial 1/4 wave
> systems. The current leader in the application of these elevated systems is
> Ron Nott of Nott Ltd. (I don't think he's a ham) and you can read a bit of
> related materials at his website:
>
> http://www.nottltd.com/AMGroundSystems.html
>
> The bottom line is that elevated radial systems can work as well as standard
> buried systems, but there are some special design considerations. The
> six-radial "gull-wing" design seems to be effective, and IIRC there was an
> article several years ago in QST about modeling such a design for 160
> meters. Any model comparisons between buried and elevated radials should be
> done with the double-precision NEC-4 engine which is not used by most
> antenna modeling programs. EZNEC Pro/4 uses NEC-4, but you have to pay an
> additional license fee.
>
> There have been hundreds of posts about this subject on the Radio-Tech
> e-mail reflector at Broadcast.net from engineers who have designed, built,
> tested and licensed several successful elevated radial systems for
> commercial broadcast use. A search of their archives can shed a lot of
> light on this subject.
>
> Ron N6IE
> www.N6IE.com
>
>
> ----- Original Message -----
> From: "Billy Cox"
> To: "Discussion of Ten-Tec Equipment"
> Sent: Saturday, August 16, 2008 9:57 AM
> Subject: Re: [TenTec] OT: Ground Radials at Tower Base
>
>
>> Sadly Derwin, you are very "missaken". Do a search
>> on W8JI, or read ON4UN's Low band DXing books to
>> learn how ground system really work.
>>
>> There is "no free lunch" with radial systems.
>>
>> 73 de Billy, AA4NU
>>
>> -----Original Message-----
>>>From: Derwin Goliver
>>>Sent: Aug 16, 2008 12:52 PM
>>>To: geraldj@storm.weather.net, Discussion of Ten-Tec Equipment
>>>
>>>Subject: Re: [TenTec] OT: Ground Radials at Tower Base
>>>
>>>Well now....
>>>As far as radials go. I like to mount my verticals off the ground.
>>>Becouse just a few 1/8 wave off the ground. Is better than many in the
>>>ground.
>>>If I am not missaken. Some thing like 2 1/8 wave off the ground =
>>>something
>>>like100 in the ground.
>>>I have a 5/8 wave 20 meter vertical with 3 off the ground (gound plane
>>>style) . Thas I made this antenna is smoken' .
>>>I mounted it on the garage roof in a tri pod. With 3 14 foot radials and
>>>a
>>>matching coil at the base.
>>>Thing is this needs guys. Becouse of its 41 1/2 foot heighth .
>>>
>>>Derwin
>>>
>>>
>>>----- Original Message -----
>>>From: "Dr. Gerald N. Johnson"
>>>To:
>>>Sent: Friday, August 15, 2008 10:40 PM
>>>Subject: Re: [TenTec] OT: Ground Radials at Tower Base
>>>
>>>
>>>> On Fri, 2008-08-15 at 19:46 -0400, Gary Hoffman wrote:
>>>>> If you improve your grounding system, you will always be happy that you
>>>>> did.
>>>>>
>>>>> To say it will or will not reduce noise requires knowing a lot more
>>>>> about
>>>>> the specific details of your setup.
>>>>
>>>> The grounding system for a vertical antenna is often deficient. That's
>>>> easily seen when the antenna SWR is low, but there's no matching
>>>> network. The perfectly grounded vertical should have a feed point about
>>>> 35 ohms. If the number of radials and ground rods is small, they can
>>>> contribute resistance to the feed point impedance raising it towards 50
>>>> ohms for a better apparent match. But with the radiation resistance 35
>>>> ohms and the ground resistance contributing half that much, the antenna
>>>> efficiency is 2/3 what it ought to be for both radiation and reception.
>>>> So improving the vertical antenna grounding (more radials, 50 is a
>>>> start, 256 is considered enough in broadcast circles, and more rods)
>>>> hurts the match but improves the antenna efficiency. That may actually
>>>> increase the noise heard, but it will increase DX signals by the same
>>>> amount so ought to be a wash. Unless a radial happens to contact a
>>>> ground from a noisy power pole.
>>>>>
>>>>> If there are grounding issues (and maybe there are not) and you fix
>>>>> them,
>>>>> it
>>>>> can certainly help.
>>>>>
>>>> The good noise reception on a vertical is why some 80 and 160 meter
>>>> DXers use a loop or Beverage for reception (directivity, not efficiency
>>>> is the goal) and the vertical only for transmission. Its hard to beat a
>>>> vertical for low angle (and thus best DX) radiation and reception, but
>>>> the propensity of a vertical to hear in all directions makes it hard
>>>> without going to an array of verticals to hear the weakest of signals
>>>> over the noise. Even atmospheric noise can be directional, so a
>>>> directional receiving antenna can be a benefit.
>>>>
>>>> 73, Jerry, K0CQ
>>>>
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