I tried to read this article, but it had equal parts of truth
and fiction. (The fictional parts were duly noted, but it is
still confusing). It would be a lot more readable if you just stated
what is now known to be true. The two ammeter photo is shocking.
I never would have thought that was happening. I still don't
understand the theory of where the current goes, but I can't
argue with the photo. Come to think of it, in a Tesla coil,
the current at the top is also not the same as the current at
the bottom. The comments about loading coil Q not
being critical are also surprising. I have always used top
loading wires, so I guess I don't have to change anything
based on this corrected information.
Rick N6RK
On 4/23/2011 9:05 AM, k3bu@optimum.net wrote:
> On the subject of resonant loaded radiator - element please see my article at
>
> http://www.k3bu.us/loadingcoils.htm
>
> it took me some 40 years to realize wasaaap with loaded elements - current
> distribution and efficiency.
> We had a duel on the subject between K3BU, W9UCW, W5DXP in one corner and
> W8JI and W7EL in another. W8JI still insists he is right.
> Measurements and experience confirm "our" argument and as result of the
> exchange, W7EL updated the EZNEC to allow real life coil with turns to be
> modeled, similar to linear hair pin loading.
>
> It boils down to distribution of the current along the standing wave element
> and efficiency is roughly proportional the area under the current curve.
> Realizing that, it makes it plain to visualize the efficiency and performance
> of the loaded antenna element. The trick is to make the high current portion
> as long (area as large) as possible. 3/8 wave loaded elements, are the best -
> large area and higher base impedance, close to 50 ohms.
>
> Linear loading is less efficient than coil, base loading worst, top loading
> is the best, loading coil about 2/3 up is a good compromise especially for
> mobile antennas.
>
> ON4UN had it right in earlier edition of his book, then W8JI convinced" him
> to change to his "truth". Many found out with their own lying eyes what truly
> works better.
>
> Happy Easter Egg to all!
>
> Yuri K3BU.us
> www.MVmanor.com home of Glen Spey RadioFest
>
>
>> <BR>> These days I use a 95 ft top loaded vertical and yes it "seems"
>> to be "slightly" better then the 90 ft base loaded however
>> this is just a feeling and I have no measurements to back it
>> up with. But as long as my brain thinks it is better it is
>> fine for me.
>>
>> Bottom line: I will never use linear loading again !!
>>
>> 73 Jim SM2EKM
>> -----------------------------------------------------------------
>> On 2011-04-21 04:42, Lars Harlin wrote:
>>> Hi Rag!
>>>
>>> Have you thought about the possibility to use linear loading?
>> That could be
>>> a good alternative when you cant put the loading on top...
>>>
>>> 73 de Lars, SM3BDZ
>>>
>>>
>>> ----- Original Message -----
>>> From: "Stein Roar Brobakken"
>>> To:
>>> Sent: Wednesday, April 20, 2011 7:11 PM
>>> Subject: Topband: 160m vertical with "top loading"
>>>
>>>
>>>> Hi
>>>>
>>>> We are going to install a 18m spiderbeam @ LA9TJA for use for 160m
>>>>
>>>> We been studying different top loading configurations, but we
>> can't have
>>>> the
>>>> wires stringed from the top because it will break the
>> spiderbeam ;)
>>>>
>> _______________________________________________
>> UR RST IS ... ... ..9 QSB QSB - hw? BK
>>
> _______________________________________________
> UR RST IS ... ... ..9 QSB QSB - hw? BK
>
>
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UR RST IS ... ... ..9 QSB QSB - hw? BK
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