Hi Mike,
As far as the ducting goes, here is some insight into the phenomena in
my old CQ article:
http://k3bu.us/propagation.htm
160 exhibits peculiarities, depending on sunspot cycle, time of the
year, solar activity.
There is polarization rolling around, angle fluctuation, spotlight
focusing and one way propagation.
Effects can be quite pronounced and frequency sensitive. Wobbling
between LW, MW and SW modes.
It is hard to tell at what time, what is happening "up there" to our
signals. You could have experienced one thing, while others were "hit"
by another. You just have to be there when "it" happens, especially when
gunning for contest records.
When I had my stacked Razors and experimented with switching vertical
angles I found that about 70% of time there was disagreement between RX
and TX best angle/antenna. And I too experienced LDEs.
As far as your 5/8 vertical over salty "ground" I can see 1. super
performance at low angles (in KH6 everything is long haul DX) and 2. for
high angle lobe (unique property of producing "all polarizations")
signals serving local area NVIS (KH6, boats etc.). Interference
cancellation circles probably fall in "no man's" area, observed on VHF
(repeaters).
After Team Vertical exploits with verticals on the beach, I explored
Cape Hatteras, NC locations and was amazed too with some 10 -15 dB
"gain" close to salt water, it was like driving into inside of the
amplifier.
Some "knowitalls" would ridicule other's findings, even managed to
"correct" ON4UN's excellent book material.
73, Yuri, K3BU.us
www.MVmanor.com place for radiofest
On Mon, Sep 09, 2013 at 02:23 PM, Mike Armstrong wrote:
> Same here, guys. Please do reply here and if someone "already knows
everything," they need not even read the thread, right? LOL. I have
heard, but don't know if it is a common mode of propagation or if it is
very rare, like LDEs on 15...... They do happen, but it is as rare as
hen's teeth. I have heard it 3 times on 15 that I am aware.... But I
digress, the mode I am wondering about, and it might explain why even I
with a low horizontal on 160 have worked some decent DX (Chile, Japan,
several Carib countries, and some pacific islands)..... Is "ducting" a
common propagation mode on 160? If it is, that could explain ALOT when
it comes to high angle radiators working DX that they probably shouldn't
even hear with such a setup.
Any thoughts from those who would like to talk about the subject of
high angle radiators (even NVIS), ducting and DX? Quite honestly,
during one particular 160 contest a couple of years ago, I worked 11
countries (all new for me) all over the place except europe...... As
strange as it seems, those were the only countries that ANYONE in my
area was hearing or working. So here I was working the same DX
stations that some guys with really decent 160 antennas were working,
but MY antenna was anything but ideal........ 300 foot long OCFD (fed
about 20 feet in from one side) and, this is the kicker, it is only up
50 feet in the air on one side and 40 feet on the other side
(available trees, one of which is on my neighbor's property..... but
she is my mother in law, so no legal issues there.... lol). So how is
it that I was working these stations with the same amount of effort as
the guys who had "ideal" antennas, like full sized 1/4 wave verticals
over an EXTENSIVE radial field.
It was a very pleasant surprise, but not expected at all.
On later dates,I would hear people in the same areas of the world, but
no matter how hard I tried, not able to work them..... although I HEAR
them quite well on that antenna (it seems to be fairly low noise).
Something has to be "up," but I will be darned if I can figure it
out..... unless there is some prop mode that is common to 160 and
isn't on other bands where this type of antenna "scaled" in length and
height would suck 100 percent of the time...... LOL. Well, maybe not
100, but often enough that EVERY antenna book would say "get it higher
in the air.... ALOT higher"
Thoughts from experienced 160 folk? Again, only those interested in
talking about this subject need respond. :) :)
Mike AB7ZU
Kuhi no ka lima, hele no ka maka
On Sep 9, 2013, at 8:56, Bill Cromwell wrote:
On 09/09/2013 10:33 AM, James Rodenkirch wrote:
...think that there's "more to understanding" horizontal and
vertical antennas on Top Band.
Listening to a fella on 80 SSB this morning about his experiences
with a vertical 1/4 wave and a horizontal loop on Top Band.
He said he had both up and used them over a 20+ year period and
noticed that one would work better than the other for DX. For five
years or so the loop would outperform, for a couple of years the two
would be equal and then for about five years the vertical would do
better.
One can easily point to the 12 year period as aligned with the Solar
Cyclef BUT -- when I look at the radiation patterns for both I see
the loop as a hugely efficient NVIS antenna with little low angle
radiation. Sooooo, I think there are some magnetic anomalies at
play here but -- if the radiation angles don't change, how does one
work "mo betta" than the other?
I do have the ON4UN book and will start diving in to it more to see
if John can shed some light on this topic AND I don't wanna start a
cuss and discuss session here (I know many of you already understand
what influences the above "observations" so I don't want to rekindle
any previous "debates) but.....if someone can direct me to specific
sections of John's book or lother papers/websites, I would
appreciate it!!
I consider myself a "newbie" re Top Band" propagation and "other
'influencers'" on antenna performance (I do understand gray line,
the various ionized layers and all of that) but anxious to learn
more - thank you, in advance, for any "direction" you can point to
so I can learn. Replies off line are probably mo betta - don't need
to get any pissin' contests agoin'! Hi Hi
72, Jim Rodenkirch _________________
Please reply on the list. I'm interested, too. My own suspicion is
there are parts of propagation that are not very well understood if
at all and those bits are pointed out by what happens with real
antennas as opposed to theoretical antennas. That does not dismiss
the theories.
I'm taking baby steps here and I am permanently limited by my postage
stamp lot but we have all read testimony about success from small
lots (and with low power). I'm cornering the parts to build a 'meter'
that will give me information about the antennas I already have so
that I might make them perform "mo bettah" - if I know whether to
turn left or right when I get some 'numbers'. Just like Jim, I am
not interested in stirring up any pots. It's pretty easy with a 40
meter dipole antenna to just go outside and cut off all the parts
that don't work. 160 meters (or 600 meters) doesn't lend itself to
that simplicity - if nothing else because of size.
73,
Bill KU8H
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Topband Reflector
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Topband Reflector
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Topband Reflector
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