[Elecraft] Inverted-L (was OT: Vertical antenna)
Vic K2VCO
vic at rakefet.com
Tue Dec 21 11:43:39 EST 2010
Guy,
How about some more details on the counterpoise? I am using a 40' vertical top-loaded with
two 44' wires (in other words, I'm feeding the feedline of my dipole as a vertical) on
160, my ground system is a bunch of elevated radials running around the eaves of my house
and some in-ground wires, and I don't 'feel loud'. I would love to replace the mess with a
better ground system.
On 12/21/2010 8:36 AM, Guy Olinger K2AV wrote:
> We are developing a new class of non-radial 160m counterpoise
> solutions. We had a few installed, and in use in the Stew Perry
> Topband Distance Challenge last weekend. (We're actually TESTING them
> before we go into blather mode, fancy that.) Look up W0UCE in the
> 3830 TBDC score listing and compare his score to others in his area
> (NC, VA, DC, PA). Nothing like contests to point out weaknesses, or
> none. As of last count, he was in the top quarter of single op high
> power scores, worldwide.
>
> W0UCE's transmit antenna had NO radials of any kind. He has a very
> minimal up 47 feet out 85 foot end-fed wire for 160 (limits dictated
> by available trees -- sound familiar?), working against a single wire
> elevated folded counterpoise, no radials. He has no space on his
> subdivision lot for beverages and used a pennant and K9AY loop for RX
> antennas. The counterpoise, while giving up on field cancellation
> loss below (the gift of DENSE radial fields) is designed to minimize
> ground induction losses underneath while being an effective
> counterpoise -- return energy for use in the RADIATING element. His
> words were "I felt loud."
>
> There ARE significant differences between actual measurements and
> model predictions (the expensive NEC4 pro EZNEC stuff) which we have
> not explained (not for lack of trying), but if you really want to test
> something, put it on line in a contest and go head to head with
> everyone else. There's no BS in contest results, just stark reality.
> You either beat or get beat (think NASCAR and tire and engine
> testing).
>
> W0UCE's signal over the period of the contest is documented in the
> Reverse Beacon Network, and we can compare it to anyone else's in the
> USA over the contest period. Jack's category of station is "small lot
> little guy, running an amp."
>
> Don, if you're interested, you're local, and we could put up one at
> your place, including the cook's tour about how we think it works.
> The 160m version of the counterpoise fits inside a a 45 degree right
> triangle that has short sides of 60 feet and a hypotenuse of 86 feet,
> to get the max out of small lots. It's specifically being designed
> for the little guy. UCE lives in Youngsville and a tour is easily
> arranged if you're interested.
>
> We won't be asking anyone to put up something we haven't already tried
> and tested.
>
> 73, Guy.
>
> On Tue, Dec 21, 2010 at 10:32 AM, Steve Ellington<n4lq at carolina.rr.com> wrote:
>> Logically .....
>>
>> You may as well have a big loss in the near-field and get it over with.
>>
>> That way you'll have less to loose in the far field!
>>
>>
>> Steve
>> N4LQ
>> ----- Original Message -----
>> From: "Guy Olinger K2AV"<olinger at bellsouth.net>
>> To: "Tony Estep"<esteptony at gmail.com>
>> Cc:<elecraft at mailman.qth.net>
>> Sent: Tuesday, December 21, 2010 10:28 AM
>> Subject: Re: [Elecraft] Inverted-L (was OT: Vertical antenna)
>>
>>
>>> The only thing I would point out about the article is that it
>>> basically is a tabulation of model results, an extension of the model
>>> presentation, what do you get if you run the model over and over kind
>>> of thing. The modeling of dirt is in itself an attempt to extend a
>>> limited paradigm of MF measurements (aka commercial broadcast band),
>>> focused on measurements at the ground for very practical reasons
>>> (Norton-Sommerfield) and has its own set of well-known issues. It is
>>> quite common to model radial kinds of issues and then install a design
>>> and find quite different results. Dirt, and all its variability,
>>> remains notoriously resistant to being modeled. Modeling can, I say
>>> "can", get one in the neighborhood and it's back to cut and measure,
>>> and a degree of common sense.
>>>
>>> 73, Guy.
>>>
>>> On Mon, Dec 20, 2010 at 10:14 PM, Tony Estep<esteptony at gmail.com> wrote:
>>>> For those who wish to pursue the radials question further, here's one of
>>>> the
>>>> many publications on the subject. This one is replete with numerous
>>>> tables
>>>> and graphical representations of the incremental value of more and longer
>>>> radials in various types of soil:
>>>>
>>>> http://www.ncjweb.com/k3lcmaxgainradials.pdf
>>>>
>>>>
>>>>
>>>> Tony KT0NY
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--
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco/
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