Jim,
It looks like you connect wires to lossy ground. Do you have the NEC-4
engine with your EZNEC ver 6.0?
Carl K9LA
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Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Thanks for the updated info, Steve.
Yes, a big Cycle 25 would still be in the picture. My little QRP 10m
transceiver will see some use! Ooops, sorry - this is the topband reflector.
Carl K9LA
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Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Guy,
I agree that looking at the magnetic cycle inside the Sun is the way to go.
The McIntosh, et al, prediction for a big cycle is based on their
assumption that the termination date for the Cycle 24 magnetic cycle was
April 2020.
But in Dr. Scott McIntosh’s presentation of November 11, 2020,
Rich N8UX,
I have Volume 1 (1998) and Volume 2 (2000).
Both are edited by N0AX, so ping him for more info.
Carl K9LA
_
Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Nick VE7DXR,
At least they corrected the vertical axis of the 10.7 cm solar flux plot -
it used to say sunspot number.
What I do for the Ap is download the data from "Table of Recent Solar
Indices (Preliminary) of Observed Monthly Mean Values" in the Data tab
below the plots and import the data
For those who are antenna challenged, don't sell a 160m inverted-vee at low
height too short.
My 160m antenna at the moment is an inverted-vee at an apex of 45 feet.
Additionally, the last third of each end is at 90 degrees to the main
portion and horizontal at only 7 feet or so off the ground.
> What the heck happened that I could hear a
> long wave signal over 2000 miles away at mid day?
For a given electron density profile, the amount of refraction incurred by
an electromagnetic wave is inversely proportional to the square of the
frequency.
The result of that is the lower the
Hi to everyone,
>From ionization rates in the scientific literature, galactic cosmic rays
(GCRs) result in more electrons down low in the ionosphere (from
collisional ionization) - where ionospheric absorption occurs. So one would
think that the more cosmic rays, the more absorption - which is
Does this mean a topic like "What Makes 160m Tick" would not be welcome?
Couldn't resist.
Carl K9LA
_
Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
For the record, that site belongs to NO8D.
Carl K9LA
_
Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
I was in the Cleveland area several weeks ago, and saw some big towers with
lots of what looks like Yagis.
This site is at 41.2312991 latitude and -81.58989168 longitude for those
who want to look at it with Google Earth. It is about 2 miles east of the
junction of I-77 and I-271, and about 17.5
What Steve and Nick VE7DXR were referring to is the geomagnetic latitude in
relation to polarization - not ground conductivity.
This involves the ordinary and extraordinary waves that propagate through
the ionosphere, and how 160m is affected by being close to the electron
gyro-frequency.
Carl
David,
The NEC-4.2 engine appears to give very good results with buried and
close-to-ground wires (the NEC-4.1 engine compares favorably, too). It is
instructive to read N6LF's July/August 2016 QEX article on his modeling
efforts with buried and close-to-ground wires.
You can get Rudy's article
Joe,
> However, the Waller Flag is a dual loop that trades off signal for
> pattern.
I agree. But I believe it's gain is very low mostly because it's made up of
electrically very small loops.
A very small loop has its main lobes in the plane of the loop - not
perpendicular to the plane of the
Note that the KK5JY antenna is a single loop, not a double loop as G3UNA
referenced.
> That's a terrible RX antenna. Did you see the losses?!
> Minus-forty-something dB on 160.
That gain value is in the neighborhood of what a Waller Flag does.
Carl K9LA
_
Topband Reflector
Mark,
> I learned that polarization is not predictable after the first
ionospheric bounce.
Theoretically, polarization is well-defined as an electromagnetic wave
progresses thru the ionosphere. What's important is the "limiting"
polarization at the entry and exit points of the ionosphere, and
Polarization - As Jerry K4SAV stated, the electron gyro-frequency plays an
important role on 160m since our ionosphere is immersed in a magnetic field
- it also affects ionospheric absorption and refraction. For those of us at
mid to high latitudes, vertical polarization on 160m is *theoretically*
Pete N4ZR said one option was to "Suspend inverted vees for 80 and 40 from
the top of the rocket launcher (right under the tribander)."
Gene AD3F commented on low inv-vees: "From what I've read on Topband and
TowerTalk over the years, a low Vee as you're proposing is likely to be a
cloud
Thanks to a big oak tree, I have used a homebrew 80m trap (large diameter
B Miniductor and high voltage doorknob caps) at the top of my 80m
quarterwave wire vertical, and a wire at the top of the trap sloped down to
a tree by the house to achieve 160m resonance. I have two 60-foot elevated
radials
Hello Kris N5KM,
Thanks for the clarification.
80m is a different story. Yes, we can predict greyline propagation on 80m
(I assume when you say greyline propagation, you mean propagation along the
terminator). And our predictions say there is still significant loss along
and near the terminator
Kris N5KM asked about greyline propagation predictions. Since his question
was posted to the topband reflector, I assume he's only asking in relation
to 160-Meters.
We do not have any reliable propagation predictions for greyline on 160m.
In fact, we really don't have any reliable propagation
Bruce K1FZ said: "I have noticed that there appears to be a link between
the start of an aurora and long path 160 meter openings."
Others have noted this interesting effect. The only physical tie between
the two that I'm aware of is that a spike in the K index can initially
improve the electron
Hi guys and gals,
After walking Snoopy and going out for breakfast this morning, I got back
on 160m around 1320z (8:20 AM local here in Ft Wayne - about a half hour
past our sunrise). Between 1324z and 1340z I worked AZ, CO and OR with
decent signals on my SAL-20 Shared Apex Loop.
I also heard
hello to everyone,
With respect to Wolf DF2PY's comment about very good propagation on polar
routes when the A index and the solar wind speed are elevated, our
understanding of what makes 160m tick is lacking. In other words, "stuff
happens".
Having said that, there have been similar reports of
About a week ago Wolf DF2PY posted a message here commenting on the recent
adverse levels of geomagnetic field activity and how it will now change for
the good - giving us good 160m propagation.
We'll certainly see less geomagnetic field activity as we move into winter,
but there's another issue
Yes, you have to distinguish between sunrise enhancements and this
so-called midnight peak.
The 17 November 1996 topband posting that I referenced from DJ8WL told of
XZ1N on 1825.5 KHz at 2130 UTC. XZ1N's sunrise would be around 2345 UTC on
Nov 17. That's 2 hrs 15 min before XZ sunrise. So this
Over the years I have seen a few comments with respect to signal peaking
around local midnight. If you search on "midnight signal peaking" in the
topband archives, you should come up with four results. The one from DJ8WL
back in Nov 96 appears to be the only relevant one that I found.
I don't
BIll (AA7XT),
There's some (but not much) measured data at HF of arriving elevation
angles (for example, Wilkins et al, Epstein et al, Utlaut et al,
Wilkins again et al, and Hallborg et al).
But I've never seen any measurements at MF. The only paper that comes
close (at least that I'm aware of)
Mike W0BTU commented:
"But I thought that it was a well-established fact that NO antenna modeling
software does well with antennas close to the ground".
Yes, I believe that's true with the NEC-2 computational engine. The NEC-2
engine is readily available to the public.
The NEC-4 computational
Let me see if I understand this.
Someone is complaining that other ops are not upholding the concept of
160-Meters being the "gentleman's band", and that same person who is
complaining uses cut letters for profanity and runs 2 kW?
Joel, maybe both of us need to stay more up to date. See you in
Rick N6RK said:
> In this webinar, it was asserted (without explanation) that
> for every 1 dB increase in RDF, you get 1.5 to 2.0 dB
> improvement in S/N ratio. I've never heard that before
> and don't even see how it makes sense. Actually, I don't
> even know how you can make generalizations
Ed N1UR said "It seems non-trivial to me as to how to maintain these remote
stations."
My guess is it was someone using the Portland, OR station in the Remote Ham
Radio network (http://www.remotehamradio.com/the-stations/). The stations
are available for a price.
I don't know whose actual
Steve,
For what it's worth, VB2T will be a multi-single from Zone 2 for CQ WW SSB
this year. You can see this at http://www.ng3k.com/Misc/cqs2015.html.
Haven't seen any Zone 2 plans yet for CQ WW CW. Keep your fingers crossed.
Carl K9LA
_
Topband Reflector Archives -
The E region critical frequency at night is around 0.45 MHz. That says any
elevation angle less than about 45 degrees at 660 KHz does not get through
the E region. The skywave plot showing the 0.25 mV/m RMS field strength
contour line is for a one-hop E mode at a distance of around 1150 km at an
Rik van Riel asked:
One big question is, where does the path loss on top band come from?
Per our current understanding of the lower ionosphere, the loss due to
absorption on 160m in the lower ionosphere at night is around 10 dB per
hop. Added to that is the loss due to multiple ground
All,
I had a quarter-wave 80m wire vertical (thanks to a pulley under the limb
of an 80ft tall oak tree) with three elevated radials. Worked great.
I bought a length of 3-inch OD BW inductor stock and got some high-voltage
door-knob capacitors to make an 80m trap. Put it at the top of the 80m
Bill,
I used four 75pF 5kV caps (I think I bought them from the local surplus
shop when it existed).
I put two in parallel, and in series with that were the other two in
parallel. Thus it was a 75pF/10kV assembly. The coil was cut to resonate at
3550 KHz or so.
Carl K9LA
_
I just put Rev B of Arrival Direction of FT5ZM in North America on
160m on my web site.
For the record, Rev A corrected an error in the original text.
Rev B addresses two issues: a problem with Figure 1, and more data
received/added to Figure 3.
The Figure 1 problem is interesting. N5IA
Hi to everyone,
A week ago I requested data from NA stations on the azimuth arrival
angle of FT5ZM on 160m and 80m. I believe I individually thanked all who
responded. But in case I missed someone - thank you!
I put together a short paper on the 160m results. It is on my web site at
Hi everyone,
For those of you in North America who worked FT5ZM on 80m and 160m and who
have directional receiving antennas, could you send me a personal e-mail (
k...@arrl.net) stating from which direction you best heard FT5ZM? And your
state/province, too.
Thanks!
Carl K9LA
_
Bill VE3CSK said I have been listening several evenings now on 160M using
my K3 in diversity mode with the TX vertical array on one receiver and a
full-wave horizontal loop on the other. The rapid apparent polarization
shifts seemed quite different from the slower QSB that we often experience
on
Terry W7KW,
Yesterday I posted a message here about the Shared Apex Loop Array.
N3OC's review of it appears in the February PVRC newsletter.
My Product Review of it will appear in the April QST. My experience with it
has been extremely favorable on 160m, 80m and 40m as I cannot put up
multiple
Thanks to everyone for your comments on polarization. I certainly agree
with Tom W8JI in that this discussion is a brain exercise (he also said
enjoyable). It forces me to delve deeper to asses whether I have a
screwed-up understanding of all of this. And he has a good point in that
this is a
channel is
adding nothing but noise.
I'm afraid just like in commercial systems with scattering or multipath
propagation, a circular polarized system is a net detriment.
73 Tom
- Original Message - From: Carl Luetzelschwab
carlluetzelsch...@gmail.com
To: topband@contesting.com
Sent
I hope everyone has had a chance to work FT5ZM on topband.
With respect to circular polarization on our HF bands (3.5 - 28 MHz) and on
6m, theory says both the ordinary and extraordinary waves propagate thru
the ionosphere with pretty much equal ionospheric absorption. Thus
circularly polarized
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