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Locked How Do you connect 4U1UN ? #FreqCal
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Robert Lorenzini
If PSKReporter shows he is hearing you but not replying he may have blacklisted
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you because you have not acknowledged his replies because you did not hear them. Bob - wd6dod On 9/2/2022 4:52 PM, Ken via groups.io wrote:
What antenna are you using? |
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d_ziolkowski
Andre- yes I also can work closer in stations, but they may be using NVIS
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antennas or nearly so. I presume 4U1UN is using a DX antenna with a low radiation angle, thus their signal shoots right over us. Just my opinion of course, I'd sure like to work them also, good for another DXCC! Dan KC2STA On Fri, Sep 2, 2022 at 7:10 PM André C <acme9283@...> wrote:
Hello Dan, problem is that I have worked all the stations on the east --
Dan Ziolkowski KC2STA SKCC #4290T Ubuntu LINUX |
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André C
Hello Dan, On their website I think they mentioned using vertical antenna on top of the building....
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-----Message d'origine-----
De : main@WSJTX.groups.io <main@WSJTX.groups.io> De la part de d_ziolkowski Envoyé : 3 septembre 2022 05:44 À : main@wsjtx.groups.io Objet : Re: [WSJTX] How Do you connect 4U1UN ? #FreqCal Andre- yes I also can work closer in stations, but they may be using NVIS antennas or nearly so. I presume 4U1UN is using a DX antenna with a low radiation angle, thus their signal shoots right over us. Just my opinion of course, I'd sure like to work them also, good for another DXCC! Dan KC2STA On Fri, Sep 2, 2022 at 7:10 PM André C <acme9283@...> wrote: Hello Dan, problem is that I have worked all the stations on the east-- Dan Ziolkowski KC2STA SKCC #4290T Ubuntu LINUX |
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Jim Brown
On 9/3/2022 2:43 AM, d_ziolkowski wrote:
Andre- yes I also can work closer in stations, but they may be using NVISThis is a myth. Study http://k9yc.com/AntennaPlanning.pdf 73, Jim K9YC |
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d_ziolkowski
Jim-
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can you be more specific as to what is a myth? And thanks for the link, I will study it. Thanks Dan KC2STA On Sat, Sep 3, 2022 at 3:02 PM Jim Brown <k9yc@...> wrote:
On 9/3/2022 2:43 AM, d_ziolkowski wrote:Andre- yes I also can work closer in stations, but they may be using NVISThis is a myth. Study http://k9yc.com/AntennaPlanning.pdf --
Dan Ziolkowski KC2STA SKCC #4290T Ubuntu LINUX |
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Ron
I've worked them a couple of times over the years and you're right, since they aren't on the air very often, there is usually a huge pileup. When that happens the rare station will usually work split and you'll hear them say "listening up" . This means that they're listening for stations calling them a few Kc up the band from the transmit frequency. You can call all day on their transmit frequency and you're not going to be able to work them because they're not listing on that frequency. The key is to listen if to see if they say "listening up". That's your clue that they're working split.
Good Luck & 73, Ron - KJ5XX |
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Gary - AG0N
On Sep 2, 2022, at 15:55, Sam Birnbaum via groups.io <w2jdb@...> wrote:You need to read about Fox and Hound and how it works. And…I don’t know where they’ve been operating F/H but it isn’t supposed to be on the normal FT8 segments. They should be publishing where they are going to be, OFF the normal channels. Gary - AG0N |
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Joe Subich, W4TV
On 2022-09-03 3:53 PM, d_ziolkowski wrote:
can you be more specific as to what is a myth?Low antennas (e.g., 15-20' above ground on 80/40 meters) for NVIS are a myth. Any horizontal antenna less than 1/4 wave above ground suffers significant loss. Maximum radiation is straight up but the "critical frequency" (frequency at which radiation at 90 degrees passes through the ionosphere) is generally well below even 80 meters most of the time. Even then, the D layer absorption during daylight kills most "straight up" RF on 80/40 meters. Even for "close in" signals, one is best served by a dipole at approximately 50 feet for 80/40/30 meters and 35 feet for 20-10 meters. 73, ... Joe, W4TV On 2022-09-03 3:53 PM, d_ziolkowski wrote: Jim- |
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Eugene Morgan
If I might clarify. NVIS Antennas are anything but a myth, and many hams without realizing it use NVIS antennas. What most people don't realize is that almost any horizontal dipole like antenna (a traditional dipole, inverted vee, G5RV, OCF, half-wave wire, an end fed wire) suspended below 1/4 wavelength above real ground is an NVIS antenna, meaning they send most of their RF energy at high angles (above 45 degrees) and yes much of that energy is absorbed in the D layer or just continues on into space. Yes they are inefficient, yes they generally do not make good DX antennas. But they do have their place.
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Model any HF dipole antenna and vary it's elevation from 1/8 of a wavelength to a full wavelength above ground and you will be able to see how the takeoff angle varies. They are real, they are not a myth, and yes they can be fairly inefficient. Gene -----Original Message-----
From: main@WSJTX.groups.io [mailto:main@WSJTX.groups.io] On Behalf Of Joe Subich, W4TV Sent: Saturday, September 3, 2022 4:30 PM To: main@WSJTX.groups.io Subject: Re: [WSJTX] How Do you connect 4U1UN ? #FreqCal On 2022-09-03 3:53 PM, d_ziolkowski wrote: > can you be more specific as to what is a myth? Low antennas (e.g., 15-20' above ground on 80/40 meters) for NVIS are a myth. Any horizontal antenna less than 1/4 wave above ground suffers significant loss. Maximum radiation is straight up but the "critical frequency" (frequency at which radiation at 90 degrees passes through the ionosphere) is generally well below even 80 meters most of the time. Even then, the D layer absorption during daylight kills most "straight up" RF on 80/40 meters. Even for "close in" signals, one is best served by a dipole at approximately 50 feet for 80/40/30 meters and 35 feet for 20-10 meters. 73, ... Joe, W4TV On 2022-09-03 3:53 PM, d_ziolkowski wrote: Jim- |
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Sam Birnbaum
Hi Gary,
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I did not write that. 73, Sam W2JDB -----Original Message-----
From: Gary - AG0N <wb0kkm@...> To: main@wsjtx.groups.io <main@WSJTX.groups.io> Sent: Sat, Sep 3, 2022 5:54 pm Subject: Re: [WSJTX] How Do you connect 4U1UN ? #FreqCal On Sep 2, 2022, at 15:55, Sam Birnbaum via groups.io <w2jdb@...> wrote:You need to read about Fox and Hound and how it works. And…I don’t know where they’ve been operating F/H but it isn’t supposed to be on the normal FT8 segments. They should be publishing where they are going to be, OFF the normal channels. Gary - AG0N |
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Joe Subich, W4TV
On 2022-09-03 7:23 PM, Eugene Morgan wrote:
If I might clarify. NVIS Antennas are anything but a myth, and many hams without realizing it use NVIS antennas.The "special properties" of NVIS antennas are a myth. Radiation at 90 degrees (straight up) from a horizontal dipole increases to a maximum at 1/4 wave above ground. However, the critical frequency (frequency at which RF passes through the ionosphere) is F(muf)*COS(@) where @ is the angle of incidence. For a 90 degree angle of incidence, F(crit) is *0 Hz* - IOW, 90 degree RF is not reflected *AT ALL* and RF close to 90 degrees is only reflected under rare conditions. At 60 degrees, the critical frequency is half the MUF ...IOW for NVIS at 20 meters the MUF needs to be above 10 meters for even 60 degree radiation! One is far better served to get the antenna above 0.32 wave high getting the peak lobe *DOWN* below 50 degrees where it will do some good. 73, ... Joe, W4TV On 2022-09-03 7:23 PM, Eugene Morgan wrote: If I might clarify. NVIS Antennas are anything but a myth, and many hams without realizing it use NVIS antennas. What most people don't realize is that almost any horizontal dipole like antenna (a traditional dipole, inverted vee, G5RV, OCF, half-wave wire, an end fed wire) suspended below 1/4 wavelength above real ground is an NVIS antenna, meaning they send most of their RF energy at high angles (above 45 degrees) and yes much of that energy is absorbed in the D layer or just continues on into space. Yes they are inefficient, yes they generally do not make good DX antennas. But they do have their place. |
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Eugene Morgan
We may be splitting hairs, NVIS antennas are not a myth. As to their "special properties," I guess one would need to define what those special properties actually are. I've never been aware the NVIS's had any special properties. The math you refer in your email is exactly correct and can be demonstrated with any antenna modeling program. I completely agree, there isn't anything special about the NVIS antenna. Now if you want to talk about misunderstood antennas the G5RV would be at the very top of my particular list. ;-) But please let's not go into that here. This forum is about WSJT-X and I'd be happy to close this thread and get back to that.
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Gene (WB7RLX) -----Original Message-----
From: main@WSJTX.groups.io [mailto:main@WSJTX.groups.io] On Behalf Of Joe Subich, W4TV Sent: Saturday, September 3, 2022 6:16 PM To: main@WSJTX.groups.io Subject: Re: [WSJTX] How Do you connect 4U1UN ? #FreqCal On 2022-09-03 7:23 PM, Eugene Morgan wrote: If I might clarify. NVIS Antennas are anything but a myth, and many> hams without realizing it use NVIS antennas. The "special properties" of NVIS antennas are a myth. Radiation at 90 degrees (straight up) from a horizontal dipole increases to a maximum at 1/4 wave above ground. However, the critical frequency (frequency at which RF passes through the ionosphere) is F(muf)*COS(@) where @ is the angle of incidence. For a 90 degree angle of incidence, F(crit) is *0 Hz* - IOW, 90 degree RF is not reflected *AT ALL* and RF close to 90 degrees is only reflected under rare conditions. At 60 degrees, the critical frequency is half the MUF ...IOW for NVIS at 20 meters the MUF needs to be above 10 meters for even 60 degree radiation! One is far better served to get the antenna above 0.32 wave high getting the peak lobe *DOWN* below 50 degrees where it will do some good. 73, ... Joe, W4TV On 2022-09-03 7:23 PM, Eugene Morgan wrote: If I might clarify. NVIS Antennas are anything but a myth, and many hams without realizing it use NVIS antennas. What most people don't realize is that almost any horizontal dipole like antenna (a traditional dipole, inverted vee, G5RV, OCF, half-wave wire, an end fed wire) suspended below 1/4 wavelength above real ground is an NVIS antenna, meaning they send most of their RF energy at high angles (above 45 degrees) and yes much of that energy is absorbed in the D layer or just continues on into space. Yes they are inefficient, yes they generally do not make good DX antennas. But they do have their place. |
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Reino Talarmo
The "special properties" of NVIS antennas are a myth.Hi Joe, There is a minor misunderstanding what MUF and critical frequency means. MUF is calculated from the critical frequency and is always higher than the critical frequency. Below the critical frequency the radio waves reflect back to ground. The angle of incidence for wave that goes direct vertical is zero i.e. cos(@) = 1. See e.g. https://en.wikipedia.org/wiki/Ionosonde. If you want to calculate the critical frequency from the MUF you need to know the @ that is used for the MUF calculation, normally distance is used instead of the incidence angle at the MUF definition. The @ is always less than 90 degrees for practical MUF values and so you will not end up to a *0 Hz* critical frequency. Lowest usable frequency (LUF) is mainly affected by the D layer absorption, but that's another story. 73, Reino OH3mA |
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Michael Black
Joe...can you explain then why an ionosonde works at all? If reflection is actually COS(@) seems they wouldn't work at all.https://en.wikipedia.org/wiki/Ionosonde
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Mike W9MDB On Saturday, September 3, 2022 at 07:16:25 PM CDT, Joe Subich, W4TV <lists@...> wrote:
On 2022-09-03 7:23 PM, Eugene Morgan wrote: If I might clarify. NVIS Antennas are anything but a myth, and many> hams without realizing it use NVIS antennas. The "special properties" of NVIS antennas are a myth. Radiation at 90 degrees (straight up) from a horizontal dipole increases to a maximum at 1/4 wave above ground. However, the critical frequency (frequency at which RF passes through the ionosphere) is F(muf)*COS(@) where @ is the angle of incidence. For a 90 degree angle of incidence, F(crit) is *0 Hz* - IOW, 90 degree RF is not reflected *AT ALL* and RF close to 90 degrees is only reflected under rare conditions. At 60 degrees, the critical frequency is half the MUF ...IOW for NVIS at 20 meters the MUF needs to be above 10 meters for even 60 degree radiation! One is far better served to get the antenna above 0.32 wave high getting the peak lobe *DOWN* below 50 degrees where it will do some good. 73, ... Joe, W4TV On 2022-09-03 7:23 PM, Eugene Morgan wrote: If I might clarify. NVIS Antennas are anything but a myth, and many hams without realizing it use NVIS antennas. What most people don't realize is that almost any horizontal dipole like antenna (a traditional dipole, inverted vee, G5RV, OCF, half-wave wire, an end fed wire) suspended below 1/4 wavelength above real ground is an NVIS antenna, meaning they send most of their RF energy at high angles (above 45 degrees) and yes much of that energy is absorbed in the D layer or just continues on into space. Yes they are inefficient, yes they generally do not make good DX antennas. But they do have their place. |
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Jim Brown
On 9/3/2022 12:53 PM, d_ziolkowski wrote:
can you be more specific as to what is a myth?That very low antennas are much better for NVIS. 73, Jim K9YC |
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Jim Brown
On 9/3/2022 4:23 PM, Eugene Morgan wrote:
If I might clarify. NVIS Antennas are anything but a myth, and many hams without realizing it use NVIS antennas. What most people don't realize is that almost any horizontal dipole like antenna (a traditional dipole, inverted vee, G5RV, OCF, half-wave wire, an end fed wire) suspended below 1/4 wavelength above real ground is an NVIS antenna, meaning they send most of their RF energy at high angles (above 45 degrees) and yes much of that energy is absorbed in the D layer or just continues on into space. Yes they are inefficient, yes they generally do not make good DX antennas. But they do have their place.Takeoff angle is a flawed concept, because when the graphs are plotted, they set the strongest radiation to the outer limit of the circle, no matter how weak it is. The link I posted plots vertical patterns for ALL heights on the same graph, so it clearly shows what W4TV stated. See Fig 36 in http://k9yc.com/AntennaPlanning.pdf, which shows that 60 ft is optimum for 80M, and 90 ft is only 1 dB weaker. Divide those heights by 2 for 40M, as shown in Table 1. They are real, they are not a myth, and yes they can be fairly inefficient.And there is a tooth fairy. I suggest that you study the link I posted. It's based on an engineering study I did for the ARRL Antenna Book, where you'll see me listed as a contributor. W4TV is correct -- the earth is a big resistor, and the closer any wire carrying antenna current is to the earth the more of transmitter's power it burns (subtracted from the radiated signal). 73, Jim K9YC |
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Eugene Morgan
Exactly, that's in part why I said they are inefficient. And I've read the material and a lot more as well and modeled and built more than I care to remember. If you have to resort to citing your credential as a way to win an disagreement then it's time to terminate this QSO, there nothing constructive that can come of it at this point. An NVIS antenna is a dipole that is generally less than 1/4 wavelength the ground. It radiates good portion of its energy above 45 degrees. And yes because they are so low to the ground a lot of that energy is wasted. How many times do I need to say they are inefficient?
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At 60' an 80 meter dipole is no longer consider an NVIS antenna based on my understanding of what an NVIS antenna is. Ditto a 40 meter at 30' or more, and so on. Take off angle is a flowed concept? Wow..... If that's what you think then there's very little point in carrying this conversation any further. I rely on low take off angles for working DX which is why I use a Quad and a vertical as my mainstay antennas. I'm going to QRT at this point. We have beat this horse to death and if all you have are credentials to try and impress me with then I think we are pretty much done at this point. 73, Gene WB7RLX -----Original Message-----
From: main@WSJTX.groups.io [mailto:main@WSJTX.groups.io] On Behalf Of Jim Brown Sent: Saturday, September 3, 2022 10:43 PM To: main@WSJTX.groups.io Subject: Re: [WSJTX] How Do you connect 4U1UN ? #FreqCal On 9/3/2022 4:23 PM, Eugene Morgan wrote: If I might clarify. NVIS Antennas are anything but a myth, and many hams without realizing it use NVIS antennas. What most people don't realize is that almost any horizontal dipole like antenna (a traditional dipole, inverted vee, G5RV, OCF, half-wave wire, an end fed wire) suspended below 1/4 wavelength above real ground is an NVIS antenna, meaning they send most of their RF energy at high angles (above 45 degrees) and yes much of that energy is absorbed in the D layer or just continues on into space. Yes they are inefficient, yes they generally do not make good DX antennas. But they do have their place.Takeoff angle is a flawed concept, because when the graphs are plotted, they set the strongest radiation to the outer limit of the circle, no matter how weak it is. The link I posted plots vertical patterns for ALL heights on the same graph, so it clearly shows what W4TV stated. See Fig 36 in http://k9yc.com/AntennaPlanning.pdf, which shows that 60 ft is optimum for 80M, and 90 ft is only 1 dB weaker. Divide those heights by 2 for 40M, as shown in Table 1. They are real, they are not a myth, and yes they can be fairly inefficient.And there is a tooth fairy. I suggest that you study the link I posted. It's based on an engineering study I did for the ARRL Antenna Book, where you'll see me listed as a contributor. W4TV is correct -- the earth is a big resistor, and the closer any wire carrying antenna current is to the earth the more of transmitter's power it burns (subtracted from the radiated signal). 73, Jim K9YC |
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Joe Subich, W4TV
On 2022-09-03 11:28 PM, Michael Black via groups.io wrote:
Joe...can you explain then why an ionosonde works at all?It's getting reflections from other than directly over head. "Normal" is 90 degrees ... COS(90)= 0. The ionosonde report shows "direction to the ionospheric returns" ... there would be no "direction" for a return from directly overhead. 73, ... Joe, W4TV On 2022-09-03 11:28 PM, Michael Black via groups.io wrote: Joe...can you explain then why an ionosonde works at all? If reflection is actually COS(@) seems they wouldn't work at all.https://en.wikipedia.org/wiki/Ionosonde |
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Joe Subich, W4TV
On 2022-09-03 7:23 PM, Eugene Morgan wrote:
Model any HF dipole antenna and vary it's elevation from 1/8 of a wavelength to a full wavelength above ground and you will be able toIt's not the takeoff angle that is important. Below 1/4 wave (the definition of an NVIS Antenna) the TOA is 90 degrees and does not vary. The issues are that F(crit) for 90 degrees is zero and that ground losses increase dramatically below 1/4 wave. NEC with perfect ground will not show those losses ... even with "high accuracy" ground NEC 2 only shows 2-3 dB of loss at 1/8 wave (it's up to 6dB at 1/16 wave or ~20' on 80 meters) but that still understates the true losses with poor ground (NEC4/NEC5 do a better job of getting at the true losses). Between ground losses below 1/8 wave, losses due to the critical frequency, losses due to D layer absorption, low antenna NVIS is just another myth. Now, if you want to confine the NVIS discussion to antennas at 20' or higher on 30 meters and above, we can discuss their utility for "close in" communications. Similarly, we can discuss the utility of antennas as low as 30' on 40 meters or 60' on 80 meters *AT NIGHT* when the MUF is lower and D layer thins/disappears. At lesser heights one is dumping 50 to 75% of the transmitter power right into the dirt and radiating another 50% right out into space. 73, ... Joe, W4TV On 2022-09-03 7:23 PM, Eugene Morgan wrote: If I might clarify. NVIS Antennas are anything but a myth, and many hams without realizing it use NVIS antennas. What most people don't realize is that almost any horizontal dipole like antenna (a traditional dipole, inverted vee, G5RV, OCF, half-wave wire, an end fed wire) suspended below 1/4 wavelength above real ground is an NVIS antenna, meaning they send most of their RF energy at high angles (above 45 degrees) and yes much of that energy is absorbed in the D layer or just continues on into space. Yes they are inefficient, yes they generally do not make good DX antennas. But they do have their place. |
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David Herring
OK, I can’t remain quiet on this one…
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According to W4TV in the last paragraph of his last message, he says in essence if one puts their dipole too low then they are losing anywhere from 100% to 125% of their transmitted power. Losses greater than 100%? That’s a neat trick! How exactly does that work? Heck, how do you even get 100% loss? Even a dummy load radiates a little bit. ;-) Some months ago, I caught all kinds of heck on here when I shared that while living on Kauai, I ran a 40 meter dipole at 15 feet above ground and got excellent results for regional communications in a circle of about 400 miles. It seemed like I could not get anyone to understand that I did not care one flying iota about losses, distance and whatever other theoretical-backed-by-science objections they threw at me. I had an antenna that *ACTUALLY* *WORKED* *PERFECTLY* for what it was intended for. Flawless, gapless, consistant, reliable, low noise 40 meter communications across the Hawaiian Islands. I respect the math, and the simulations and the modeling and the engineering credentials and such as that…goodness knows I’ve done plenty of it myself. But at some point, like for example when you think you’re getting 125% losses, we as hams need to pull our noses out from the books and computers and go stick some wire up in the air and try it. And with that, I am donning my asbestos suit and making myself scarce… ;-) 73, Dave - N5DCH On Sep 4, 2022, at 8:25 AM, Joe Subich, W4TV <lists@...> wrote: |
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