Gee, I wonder if Carl had any idea what a "catfight" he was going to start,
when he began this thread?
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!
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
-----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..... :) :)
Kuhi no ka lima, hele no ka maka
On Sep 6, 2013, at 17:34, Mike Waters <mikewate@gmail.com> wrote:
> Like Tom said earlier, it's all about ground loss. Near the sea, a 1/2 or
> 5/8 wave vertical may perform very differently than a duplicate antenna a
> long way from the sea. The near-field and far-field losses at the lower
> angles would be much lower.
>
> 73, Mike
> www.w0btu.com
>
>
> On Fri, Sep 6, 2013 at 7:04 PM, Bob K6UJ <k6uj@pacbell.net> wrote:
>
>> Mike,
>>
>> Tom, W8JI has a comparison between 1/4 wave and 5/8 wave vertical mobile
>> antennas here: http://www.w8ji.com/VHF%20mobile%20vertical.htm
>> He is comparing mobile antennas but it looks like the 5/8 wave can be 2
db
>> better than the 1/4 wave.
>> Looking at the radiation angle graphs it shows the 5/8 has more gain at
>> lower radiation angles in particular.
>> If you were doing your comparison on long haul contacts it makes sense
>> that the 5/8 would do better.
>>
>> Bob
>> K6UJ
>>
>>
>>
>> On Sep 6, 2013, at 4:35 PM, Mike Armstrong wrote:
>>
>>> Guy, you aren't reading my emails...... because that question is not
>> appropriate to the conversation. I am NOT, I repeat NOT talking the
>> difference between LOCATIONS, but the difference between ANTENNAS AT THE
>> SAME LOCATION! I am NOT talking about RURAL ANYTHING. That location
being
>> on Gannet Avenue across from the Marina that was LITERALLY across the
>> street from my house.
>>>
>>> I say again, READ MY EMAIL as your question has absolutely NOTHING to do
>> with the conversation. The fact that you sent the same email to me after
I
>> answered you tells me that you are not reading what I wrote. I am not
>> being insulting, but if you don't read ALL of what I wrote, you cannot
>> possibly ask a valid question or make any statements about its content.
If
>> you read it, you would know that I am not saying ANYTHING about location
>> changes or differences. OF COURSE a sea water location is better than a
>> rural location. THAT fact has nothing to do with the comparisons I am
>> making or asking Tom to discuss. Sorry for the repetition, but I want to
>> make sure that you will see that, even if you don't read this email
>> entirely. Again, no insult intended, but it is tiring trying to respond
to
>> someone who isn't reading ALL of what I wrote and jumping to incorrect
>> conclusions as a result. I WILL tell you the address, if you still want
to
>> know, after you have read and responded
>> to
>>> the content of this email specifically.
>>>
>>> Mike AB7ZU
>>>
>>> Kuhi no ka lima, hele no ka maka
>>>
>>> On Sep 6, 2013, at 13:38, Guy Olinger K2AV <olinger@bellsouth.net>
>> wrote:
>>>
>>>> Mike, could you kindly supply the address on Iroquois Point? If it's
in
>>>> the area I'm looking at with Google Earth, the answer why the
>> difference is
>>>> pretty plain, and points to why such a difference vs. a 160m vertical
on
>>>> rural terra firma.
>>>>
>>>> 73, Guy.
>>>>
>>>>
>>>> On Fri, Sep 6, 2013 at 1:30 PM, Mike Armstrong <armstrmj@aol.com>
>> wrote:
>>>>
>>>>> Oh, I didn't address one comment you made, Tom...... 5/8ths are dogs
on
>>>>> 160? Really? That is odd in the extreme to me. I had incredible
>> success
>>>>> with a ground mounted 5/8 on 20 meters while I was stationed in
>> Hawaii. I
>>>>> was rather space limited, so I could only go up and a tower mounted
>> beam
>>>>> was a "no fly zone" in that particular situation. So, I decided to
>> try the
>>>>> 5/8ths wave vertical and its performance was nothing short of
>> spectacular
>>>>> when compared to a 1/4 under the same circumstances. Not to malign
the
>>>>> simple 1/4 wave, but the 5/8ths performance improvement went way
beyond
>>>>> what I would have expected...... and my expectations were certainly
>>>>> reasonable. My thinking was that lifting the major current node a bit
>>>>> above ground would probably be an improvement and, to my surprise,
>> that was
>>>>> an understatement in the extreme.
>>>>>
>>>>> I wouldn't want to overblow the results, but I simply couldn't believe
>> how
>>>>> well the antenna performed on 20. To be sure, I was on Oahu out in
>>>>> Iroquois Point housing, which is well situated with regard to the sea
>> (you
>>>>> are basically ON the water in almost all directions). Additionally, I
>> had
>>>>> 60 radials underneath the thing, spread evenly around the base (in
>> straight
>>>>> lines, no bending). So it was definitely an ideal vertical location.
>> But
>>>>> the difference between it and the quarter wave was what truly
>> surprised me
>>>>> (with all else being the same.... sea water location, number and
>> length of
>>>>> radials, etc). To hear that it doesn't translate to 160 is really a
>>>>> surprise to me...... Tell me more, assuming you did any kind of study
>> into
>>>>> why it didn't seem to work well. I am as interested in why something
>>>>> DIDN'T work as I am in why it does..... If for no other reason than to
>> save
>>>>> a few bucks and alot of time.... LOL
>>>>>
>>>>> Mike AB7ZU
>>>>>
>>>>> Kuhi no ka lima, hele no ka maka
>>>>>
>>>>> On Sep 6, 2013, at 9:25, "Tom W8JI" <w8ji@w8ji.com> wrote:
>>>>>
>>>>>>> Fully understood. I wasn't referring to the usual collinear
antennas
>>>>> sold by "comet" or anything of that nature. I am referring to the
>> stacking
>>>>> arrangements used for ops like moonbounce, etc. As far as the design
>>>>> theory (and practical application) goes, I have a reasonable amount of
>>>>> schooling and experience (been active since 1966..... he he he). Just
>> so
>>>>> you realize I am not referring to the often (always?) false gain
claims
>>>>> made by manufacturers for their antenna designs.
>>>>>>
>>>>>> ........but this is verticals, and not a narrow BW like a long Yagi.
>> The
>>>>> narrower the pattern of a cell in the stack, the wider minimum useful
>>>>> stacking distance becomes.
>>>>>>
>>>>>> Also, for 160, antennas are near earth. Earth spoils everything. A
160
>>>>> antenna at 260 feet is like a two meter antenna at 3.25 feet above
>> ground.
>>>>>>
>>>>>>
>>>>>>> All I was saying was, "yes, it is possible and is done" when
speaking
>>>>> to vertical stacking. As far as stacking what we would call "ground
>> plane"
>>>>> antennas (quarter wave vertical element against elevated radials), the
>> only
>>>>> example I have seen with any regularity is done aboard some Naval
>> vessels
>>>>> (stacked/phased, if you will, horizontally on a yard arm). I "think" I
>> have
>>>>> seen the same thing at airports, but I cannot tell for certain that
>> they
>>>>> are phased arrays or just happen to "look" like they are related.
>>>>> Understand that in all cases to which I refer, including my own, I am
>>>>> speaking of phased arrays, which I believe is what we are talking
>> about as
>>>>> well. I may have misinterpreted the question to some degree.
>>>>>>
>>>>>> This is 160. The distance ratio for the same behavior on two meters
is
>>>>> 80:1. If we look at:
>> http://www.w8ji.com/stacking_broadside_collinear.htm
>>>>>>
>>>>>> we see **freespace** short dipole stacking distances, between current
>>>>> maximums, is 0.35 WL for 1 dB stacking gain. This is for freespace.
>> That
>>>>> means the current maximums have to be .35*160 = 56 meters apart **if**
>> the
>>>>> elements are in freespace. They have to be even further apart if near
>>>>> earth, because the earth reflection already compresses the vertical
>>>>> pattern. I'd guess, for 1 dB stacking gain over a ground mounted
>> vertical
>>>>> (ignoring ground losses), we could move the lower current maximum to
>> about
>>>>> 50 meters above earth and eliminate the upper element. That would
>> pretty
>>>>> much be a vertical dipole. If we wanted to get 2-3 dB gain, we'd
>> probably
>>>>> need 300 feet of height and an inverted groundplane at the top.
>>>>>>
>>>>>> For 160, is it is a useless endeavor at normal heights.
>>>>>>
>>>>>> Making matters worse, 5/8th wave verticals are dogs on 160. Been
>> there,
>>>>> done that, used them. A 1/4 wave vertical, or something up to maybe
200
>>>>> feet, is actually better. They have never worked well here, they never
>>>>> worked when I used broadcast towers, and when W8LT used them in 160
>>>>> contests they were also pretty weak.
>>>>>>
>>>>>> The whole thing is a waste of time on 160. Even if someone could run
a
>>>>> vertical collinear with useful gain, it would just kill their signal
by
>>>>> focusing it at too low an angle for 160, while nulling more useful
>> angles.
>>>>>>
>>>>>> 73 Tom
>>>>> _________________
>>>>> Topband Reflector
>>>> _________________
>>>> Topband Reflector
>>> _________________
>>> Topband Reflector
>>
>> _________________
>> Topband Reflector
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