[TowerTalk] One of our own...

[Bob K6UJ]

Dave,

Wow, forget to take your medication ?

Bob
K6UJ


On 5/25/16 12:20 PM, David Gilbert wrote:
>
> It's ridiculous to say that a loop is always better than a dipole, 
> especially when your only evidence is one anecdotal example. There are 
> some solid theoretical reasons why a dipole might easily perform 
> better than a loop when the supporting structures for each are at the 
> same height.  You can choose to be oblivious to those if you want, but 
> the kind of statement you just made is what made ham radio the petri 
> dish for unscientific speculation and bias in decades past.  I thought 
> we had mostly progressed beyond that, but apparently not.
>
> To be specific in your case, that narrow bandwidth for the dipole 
> could have meant that it was very efficient ... i.e., high Q ... 
> although a 15 KHz bandwidth is unusually narrow and suggests that you 
> had something else going on.  If you understood antennas you would 
> have known that and investigated further instead of just taking it 
> down.   Maybe you weren't using a balun and had feedline interactions, 
> or maybe your feedline length just happened to be a problem for that 
> particular setup.  Could have been something else as well, but it 
> doesn't make a dipole inherently a bad idea just because there was 
> something wrong with yours.
>
> Your loop likely has significantly higher losses since the bottom 
> portion is so close to the ground, and especially since a significant 
> portion of the polarization would be horizontal (tilted and bottom 
> corner feed).  The higher losses would indeed make it tune more 
> broadly and would make it quieter, but it wouldn't make it a "better" 
> antenna if you were trying to actually radiate a stronger signal.
>
> Dave   AB7E
>
>
>
> On 5/25/2016 9:01 AM, Courtney Judd wrote:
>>
>> hey Steve, yes, I did enjoy the article about verticals/beach, very 
>> educational! BUT, in the same issue of QST another article "If you 
>> can hang a full-size vertical loop, then hang a dipole" really made 
>> me roll my eyes. While I have never done any modeling, 50 plus years 
>> of playing with various antennas leaves me with the opposite 
>> conclusion.  A loop is ALWAYS better than a dipole in my experience. 
>> I wanted to spend some time on 160 some years back so I strung up a 
>> dipole at 110 ft with the resonant point at 1840.00.... worked 
>> great.... all kinds of dx.... BUT the 2:1 swr points were only 7.5 kz 
>> up and down... even with a tuner the antenna preformed poorly beyond 
>> that.  It was just un-satisfactory so i pulled it down and replaced 
>> it with the 160 antenna I still use today. A full wave loop fed at a 
>> lower corner, top at the same 110 ft point. I did have to tilt it 15 
>> deg from the vertical to get it in the property lines but it works 
>> like a bandit. It is quiet and broad banded: 2:1 is 1800 to 1890 and 
>> works well over the whole frequency! I would NEVER replace it with a 
>> dipole. Well, thats my 2 cents and I am sticking to it! lol, 73's 
>> Cort K4WI
>>> K7LXC--- via TowerTalk <mailto:towertalk at contesting.com>
>>> Wednesday, May 25, 2016 10:32 AM
>>> Howdy, TowerTalkians --
>>>
>>> One of our esteemed members, Grant, KZ1W, has had an article published
>>> in the new QST called "Verticals On The Beach - Some Modeling Results".
>>> It's a well thought out article with actual on-the-air performance 
>>> compared
>>> to predicted modeling results. A real practical article for anyone
>>> interested in vertical performance.
>>>
>>> Cheers,
>>> Steve K7LXC
>>> _______________________________________________
>>>
>>>
>>>
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