No I haven't attempted that modeling exercise, Carl. I mostly model things
I can build of wire and/or tubing. That's new information about the tower
not being grounded, I think. Do you feed it at the base for 160? Or is it
shunt-fed? - Or is it even your 160 antenna? What's on top? I assume that
there are also feed-lines running up the tower?
I did model my 5-band home-brew quad on my little 40' tower.
Regards,
Charlie
-----Original Message-----
From: Carl [mailto:km1h@jeremy.mv.com]
Sent: Saturday, September 07, 2013 3:04 PM
To: Charlie Cunningham; 'Mike Armstrong'; 'Mike Waters';
mapa50@windstream.net; Tom W8JI; paul@n1bug.com; Bob Kupps; Guy Olinger
K2AV; Bruce
Cc: 'topband'
Subject: Re: Topband: Are stacked verticals feasible?
Subject: Re: Topband: Are stacked verticals feasible?
> Gee, I wonder if Carl had any idea what a "catfight" he was going to
> start,
> when he began this thread?
** Nope but what dissapoints me is that no one has modeled this and one just
tells past tales of irrelevant attempts at doing something not related.
As I said at the very beginning this was posted just as an exercise. But if
someone wants to model it assume a 400' tower or higher for 160, 200' + for
80 and even 40. All with the same 12' spacing from the tower.
> For my money, if I had enough support height to support two 1/4 wave
> ground
> planes, one above the other, I'd install a vertical 1/2 wave dipole and
> get
> the current maximum higher above ground to reduce the ground losses. No
> radials required!
** And no improvement if still hanging from the same tower which may or may
not ruin the performance.
At a past QTH I had a 100' shunt fed tower on 160 that was resonant at
around 1400kHz due to the top loading of stacked 10-15-20M 4 el yagis.
Hanging from the same tower was a 80M delta loop, vertically polarized, and
about 6' from the tower that matched as predicted, worked very well to the
point of enabling me to confirm the first 5BWAZ from New England as well as
winning the US in DX contests.
> But I think Carl's proposed location for the vertical elements 6-12' from
> the tower face is way too close especially for 160 or 80 meters! Not
> likely
> to be a good radiator with a desirable pattern, I expect. Furthermore,
> the
> electrical height of the tower would play a very significant role!
>
> 73,
> Charlie, K4OTV
** Have you modeled the pattern distortion of a 12 to 18" non resonant tower
at various spacings and different bands Charlie?
Trying to confuse the issue by using 2M doesnt work either as now the tower
face is a significant part of a wavelength and in fact just about 1/4 wave
for Rohn 45/55 tower.
My own tower has no RF ground as all guys are broken up and the base sits on
a pier pin.
Anybody else have something to offer...on the subject matter please.
Carl
KM1H
> -----Original Message-----
> From: Topband [mailto:topband-bounces@contesting.com] On Behalf Of Mike
> Armstrong
> Sent: Friday, September 06, 2013 9:46 PM
> To: Mike Waters
> Cc: topband
> Subject: Re: Topband: Are stacked verticals feasible?
>
> Mike, you are answering the wrong question. Guy didn't understand the
> question at all. I KNOW that sea water is a better ground than dirt......
> The comparison I was ALWAYS talking about had NOTHING AT ALL to do with
> LOCATION! NOTHING! The comparison was a quarter wave vertical compared
> to
> a 5/8ths wave vertical IN THE EXACT SAME LOCATION...... Sorry Mike, I am
> taking it out on you and it wasn't your fault. People are responding who
> didn't actually read what I wrote, then they comment..... and they YOU
> commented on their comment which had the wrong premise to begin with.....
> I
> say again, the comparison had nothing to do with the actual location, but
> rather two different vertical types in the exact same place..... Well, ok,
> a
> few yards apart, but with the same number of radials and the same seawater
> location (Iroquois Point Military Housing on Oahu). THe words RURAL or
> DIRT
> were used nowhere in my original email.
>
> What intrigued me was that I had such a great experience with a 5/8 wave
> vertical over a 1/4 wave vertical AT THE SAME LOCATION..... and on 20
> meters. Tom commented that 5/8 waves were basically garbage on 160 and I
> would like to know why..... IF he knew or had a clue as to the why. Then
> Guy started talking about seawater vs rural dirt and off the entire thread
> goes in the wrong direction...... a direction that indicated he was
> reading
> stuff into my post that just wasn't there. It is exasperating in the
> extreme to have that happen, then others like yourself are misdirected by
> their misdirection because you read theirs instead of mine..... Not
> knowing
> that they actually didn't read what I wrote. NOT YOUR FAULT, but
> exasperating because I feel compelled to answer you because you were kind
> enough to provide some details, but details to an issue that I wouldn't
> have
> mentioned because I KNOW that salt water is better than dirt..... I've
> lived
> in Hawaii, within yards of the oce
> an and then Arizona, which probably has the world's least conductive dirt
> on the entire planet.
>
> My desire IS STILL to have someone who might know give me a clue as to why
> the 5/8 doesn't work well on 160 when it works so fabulously well on 20
> meters (for one band). I use one out here in AZ on 20, too. It has alot
> of
> straight copper radials underneath it (60 half-wave long radials to be
> precise) and it works as well here, anecdotally speaking, as it did in
> Hawaii..... Well, not "quite" as good, but darned close if you take into
> account the difference in solar activity, too. When I was on Hawaii, the
> spots were a whole lot better, even tho they were decreasing, than they
> are
> today at the current "peak." If "peak" is the right word for this
> one.....
> he he he. But I digress.... I find it interesting that an antenna that
> appears to work so well on 20 as a ground mounted vertical, can be so bad
> on
> 160..... I would like to know why.....
>
> Thanks for responding Mike. I am sure you will get the gist of what I was
> talking about, now. No insults intended towards anyone, but this does
> provide a good example of what happens when folks don't read the entire
> email someone sends and then comment on it....... Then others, who have no
> idea that the person responding didn't read the email all the way thru or
> thoroughly, respond to the responder...... and away she goes..... LOL. I
> was starting to get a little wound around the axle, but now it is just
> funny. Between you and me (ha ha ha) I am not going to respond to
> anything
> else concerning my email unless someone wants to discuss the question I
> actually, really and truly had..... LOL.
>
> Speaking of which, other than the possibility that a 5/8ths wave vertical
> lays down a very low angle radiation and it is "too low" for 160
> (although,
> I have to admit that for DX work, that is a hard pill to swallow..... but
> I
> am NOT an expert on 160, which is why I read the forum comments here in
> the
> first place :) :) Like I said, when I replaced the 1/4 wave with the 5/8
> wave ground mounted vertical (20 meters only), the unsolicited comments
> concerning my signal were universally positive. I was one of the early
> WINLINK stations and my station being in Hawaii at the time was used by
> MANY, MANY sailboat guys out in the Pacific and, particularly, the Western
> Pacific. Many of the guys who used my system were former or retired
> military having a ball sailing the ocean blue...... Anyway, I needed a
> good,
> solid performer that, by necessity, had to be omnidirectional in nature.
> So
> I tried the 5/8ths and batta-bing, batta-boom I start getting UNSOLICITED
> reports in my emails that
> say something to the effect, "what did you do? You are definitely
> stronger.... in fact, you are downright LOUD now." That kind of report.
> Again, they didn't have a clue I had recently changed my winlink dedicated
> system antenna, but all of a sudden I am louder than they are used to
> hearing me. The only difference was a 5/8 wave radiator as opposed to a
> 1/4
> wave radiator over the same ground....... I then ran some test with some
> of
> my friends floating around out towards the Philippines and they confirmed,
> via an a/b test that the 5/8 wave was louder. I switched which one was
> "A"
> and which one was "B" randomly throughout the tests and not once did any
> of
> them pick the 1/4 as the better antenna. SOOOOOOOOOO, looks like I found a
> winner for my 20 meter winlink node and that antenna is definitely a go-to
> when I need a solid, omni on 20 meters. I am going to turn my station
> into
> a winlink node, once again, here shortly because my setup, which includes
> a
> 5/8 on 20 meters over
> 60 copper radials on TOP of AZ DIRT, seems to work almost as well as it
> did
> on Hawaii back in the day (all things considered, like the fact that this
> solar cycle blows chunks).
>
> Mike, I am sorry this turned into a book, but maybe now you know the whys
> and wherefores ..... as well as why it still interests me. I would have
> never even thought that a 5/8ths wave wouldn't work well on 160 until Tom
> said something to that effect..... which, due to my experience with that
> particular vertical antenna, made me say, " HUH?" LOL LOL. If you have
> any
> input on the possible WHY of that statement from Tom, I am all ears.....
> :)
>
> Mike AB7ZU
>
> P.S. I hope nobody was insulted by my little diatribe. It wasn't intended
> to insult, but just to remind folks that WE really need to read and try to
> fully digest what someone says (ALL OF IT) before we respond and possibly
> really confuse the entire thread. I include MYSELF in that statement for
> sure and certain, since I have definitely done the very same thing in the
> past. Not here, I don't think, but certainly in other ways and on other
> days..... :) :)
>
>
>
>>
_________________
Topband Reflector
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