Topband: Elevated Radials

[Pete Smith N4ZR]

The other rule that seems to apply, based on a number of pretty serious 
articles, including K3LC's NCJ series in the mid-2000s,is "they that 
has, gets."  By which I mean, if you have good ground conductivity, a 
relatively sparse radial field can work better than a really extensive 
radial field on lousy ground.

73, Pete N4ZR
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On 3/6/2013 11:54 AM, ZR wrote:
> Since the radial field for any height vertical has equal importance 
> the only way to get 1/4 wave efficiency is to have zero RF loss in the 
> loading coil and matching network. Cryogenics anyone?
>
> There is no magic wire minimalist radial or counterpoise that 
> accomplishes that. All they provide is some improvement over a poor on 
> ground radial attempt; I wont call it a radial system.
>
> Carl
> KM1H
>
>
>
> ----- Original Message ----- From: "Rick Karlquist" 
> <richard at karlquist.com>
> To: <topband at contesting.com>
> Sent: Tuesday, March 05, 2013 8:42 PM
> Subject: Re: Topband: Elevated Radials
>
>
>> One of the problems with discussing this topic is that
>> nearly all studies of radials deal with 1/4 wave verticals.
>> Most ham stations including mine don't have the luxury of
>> a height of 130 feet.
>>
>> There are many cases where some "novel" grounding scheme
>> is touted as "just as good as 120 radials" and indeed it
>> may be for the 1/4 wave height case.
>>
>> What is scarce is advice for the owner of a short vertical
>> as to what to do about grounding.  What grounding scheme
>> would it take to make the proverbial 43 foot vertical play
>> as good as a 130 foot vertical?  Whatever that scheme is,
>> we know that it will have very narrow bandwidth.  This is
>> a good litmus test to separate short vertical installations
>> worthy of additional testing from low efficiency ones.  Of course, 
>> narrow
>> bandwidth is merely necessary, but not sufficient, to
>> prove high efficiency.  The advantage of the bandwidth
>> criterion is that it is easily and unambiguously measured,
>> as opposed to field strength.  The bandwidth should ideally
>> be determined by measuring the antenna drive impedance
>> directly, rather than looking at it through a matching
>> network.  A matching network will to a greater or lesser
>> extent decrease the bandwidth of the antenna.  Alternately,
>> the matching network can be modeled to remove its effect
>> on bandwidth.
>>
>> I think it is less likely that you can be fooled by a bandwidth
>> measurement than you can with base impedance measurements.
>>
>>
>> Rick
>> N6RK
>>
>>
>>
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>> Topband Reflector
>>
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