Did we say the exact same thing? No. Did we mean the same thing? You bet,
and we both UNDERSTOOD that.
The rest you inferred based on your own assumptions, biases, etc, which is
fine, but I didn’t agree to be bound by them. When I make a post I don’t
expect that someone is going to parse each word and compare it that of another
person’s post and then “grade it” as though we were still in English class.
Sure I did my homework ahead of time but my inclination was to build it and put
it up anyway just to see how it performed. I felt better about it after I
modeled it even though I was using software which was not designed to provide a
perfect representation of my qth with stacking heights over my wildly varying
topography in each direction. And while the antenna on 15 and stacking combos
kicked butt at 109’, a similar stacking proposition for 10 meters with an
antenna at 65’ stacked with others at 100’ and lower heights did NOT work as
the model predicted. In fact the 10 meter antenna at 65’ performed poorly in a
stack with all other antenna heights and by itself in every direction BUT
towards Europe.
So “put it up” and try it had great results on 15 and mixed results on 10,
whereas the model which predicted a great stacking pattern in all directions
for both antennas on 10 and 15 also had mixed results. Ultimately I removed
the sidemount @ 65’ for 10 – it was useless to rotate the antenna at that
height for stacking purposes at my qth – it was never better than another
antenna combo. So, no model is foolproof.
My comments stand. Mark and I meant essentially the same thing even though we
didn’t say it exactly the same way – his comment after my post made that clear.
And it is silly that we would even need to have this conversation.
Bob KQ2M
From: David Gilbert
Sent: Tuesday, September 10, 2019 7:11 PM
To: towertalk@contesting.com
Subject: Re: [TowerTalk] "experts" on loading towers on low bands
Not to beat a dead horse, but no ... you aren't saying the same thing.
N5OT said to just build it and see if it works "good enough", without
further understanding or even without anything to compare it against.
Conversely, you said you relied on the K6STI's model to "do your
homework ahead of time" and that you trusted the model over someone
else's experience whether or not it was good enough.
Those are opposite approaches whether you recognize it or not, and for
the record I would have done what you did as opposed to N5OT's
approach. I'm a firm believer that as practitioners of a technical
hobby we should make an effort to understand the science of what we're
doing BEFORE we make the tradeoff decisions of cost, time, effort,
hassle, need, probability of success, etc.
Dave AB7E
On 9/10/2019 3:24 PM, Bob Shohet, KQ2M wrote:
> Actually we are saying the same thing.
>
> 1) Build it and put it up!
>
> 2) Take it down or adjust it and put it back up again.
>
> 3) Repeat as needed.
>
> 4) Get on and make lots of q’s and have fun
>
> In each case you clearly have a specific design in mind – a model or plan
> whether computer generated, hand drawn or something else, with measurements
> that we use to build what we put up. We don’t just invent it in our head
> with random materials and random measurements and slap it together.
>
> In addition, while modeling programs are based on math and theory, they are
> far from absolute; especially when dealing with terrain where the
> measurements are not absolute either. And all computer programs have points
> of inflection where the results change greatly based on the tiniest of
> dimension changes and those dramatic result changes are artifacts of software
> program limitations. Anyone who does a lot of computer modeling knows that.
> Theory is not the same thing as reality. Modeling programs are “guestimates”
> at best.
>
> The rest of your comments are not worthy of a response.
>
> Bob KQ2M
>
>
> From: David Gilbert
> Sent: Tuesday, September 10, 2019 6:01 PM
> To: towertalk@contesting.com
> Subject: Re: [TowerTalk] "experts" on loading towers on low bands
>
>
> You and N5OT aren't saying the same thing at all. He said to just
> experiment and see what works well enough to be acceptable, while you
> said you ignored the practical experience of other hams (stuff that
> "works" or doesn't) and instead used a modeling program (which is based
> purely on math and theory) to make your decision.
>
> It's odd to see two guys pat each other on the back for reinforcement
> when they don't even understand they have opposite stances. Whatever
> happened to logical thinking?
>
> Dave AB7E
>
>
> On 9/10/2019 1:44 PM, Bob Shohet, KQ2M wrote:
>> Mark has nailed it!
>>
>> One of the nice things about making something and seeing it it works well
>> enough is that what you make doesn’t know how well it is supposed to work
>> and doesn’t care. :-)
>> So if it works it works regardless of what anyone thought beforehand.
>>
>> Usually if it works (and no one thought it would), we find out long after
>> the fact why it worked, and generally it was something that wasn’t known or
>> understood at the time, and now the field advances with the “Gee, I wonder
>> why it works so well?” study and discoveries afterwards.
>>
>> Simple example... I wanted to put up a 4-stack on 15 meters when I built my
>> station. I new that I needed heights of 30’, 60’ and 90’, but with 100’ of
>> tower it didn’t seem to make sense to put another 15 above that. The
>> thinking was that even on a tall mast, the 90’ and another 15 at 109’ would
>> be too close and would phase poorly especially if they were pointed in
>> different directions. Everyone that I asked about this said so. These guys
>> built great stations and are great ops. You know all of their calls. But I
>> modeled the stack with K6STI’s YO and it looked GOOD! I asked them again.
>> “NO! I would not do it” came the answer in unison. Thankfully I did my
>> homework beforehand and I chose not to listen to the advice of people that I
>> respect.
>>
>> So I built it and put it up anyway. The 5L at 109’ was and is a KILLER!,
>> especially when in phase with the 90’. I believed the modeling over my
>> terrain. The software was correct and my 15 meter experience has been
>> awesome for the past 20 years. (And I have thanked Brian, K6STI many times
>> over the years)
>>
>> Before I put it up I reasoned that if it didn’t work I could always take it
>> down. But if it did work, I would never want to! :-) Very high reward to
>> risk ratio!
>>
>> Moral of the story: Model it, build it well, put it up and see how it does!
>>
>> 73
>>
>> Bob KQ2M
>>
>>
>> From: Mark - N5OT
>> Sent: Tuesday, September 10, 2019 4:11 PM
>> To: towertalk@contesting.com
>> Subject: Re: [TowerTalk] "experts" on loading towers on low bands
>>
>> I'm a big fan of "experiment trumps theory" and basically I have spent
>> nearly 50 years doing the following:
>>
>> 1. Make something.
>> 2. See if it works well enough.
>> 3. If it works well enough, you're done. If it doesn't, change
>> something and see what happens.
>>
>> Clearly I'm just an amateur. But because I'm on TowerTalk™ I can say I
>> make "educated guesses."
>>
>> Love you guys,
>> 73 - Mark N5OT
>> (intended to be humorous - everyone carries a bucket of gasoline in one
>> hand and a bucket of water in the other - they get to choose which one
>> they throw on the fire - I choose water) (most of the time)
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