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This Week in Amateur Radio
- PODCAST: This Week in Amateur Radio Edition #1323 β Truncated 1-hour version
Exploring Shortwave Radio Signals: A Peek into Non-Local Communications
PODCAST: This Week in Amateur Radio Edition #1322 β Full Version
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This Week in Amateur Radio
- PODCAST: This Week in Amateur Radio Edition #1322 β Truncated 1-hour version
PODCAST: This Week in Amateur Radio Edition #1322 β Truncated 1-hour version
PODCAST: This Week in Amateur Radio Edition #1321 β Full Version
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This Week in Amateur Radio
- PODCAST: This Week in Amateur Radio Edition #1321 β Truncated 1-hour version
PODCAST: This Week in Amateur Radio Edition #1321 β Truncated 1-hour version
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Copasetic Flow
- Antipodal HF Radiation: Or How Did TouCans Talk to Nighttime Australia and Japan after Sunrise in CO?
Antipodal HF Radiation: Or How Did TouCans Talk to Nighttime Australia and Japan after Sunrise in CO?
Β On one of the most interesting radio days of our recent camping trip, Project TouCans made QSOs with Australia, Japan, Columbia, and Argentina, all on the same day! The QSOs to Japan and Australia were made in the middle of their night. The Japan, Australia, and Columbia QSOs were all made in a sixteen minute window beginning with VK3YV at 12:40 UTC.
What was the Propagation Mode?
Chordal Modes Introduced with Villard
Finding Our Antipodal Point
To find the anitpoidal point, we can follow our longitude over the North (or South for that matter) where it will become the same longitude minus 180 degrees, or pi radians if that's the unit you prefer. You can see this in the diagram below where our longitude of about -107 degrees traced over the pole becomes about 73 degrees.
Meanwhile, our latitude above the equator will be used to find the same number of degrees below the equator:
37.82275 becomes -37.82275.
More precisely, we getΒ
37.822754Β°N 107.717935Β°W -> 37.822754Β°NΒ 72.282065Β°E
And our anitpodal is shown below near the 70 degrees East label.
Pretty excellent discussion of anitpodal points.
Conclusions for the moment
PODCAST: This Week in Amateur Radio Edition #1320 β Full Version
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This Week in Amateur Radio
- PODCAST: This Week in Amateur Radio Edition #1320 β Truncated 1-hour version
PODCAST: This Week in Amateur Radio Edition #1320 β Truncated 1-hour version
PODCAST: This Week in Amateur Radio Edition #1319 β Full Version
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This Week in Amateur Radio
- PODCAST: This Week in Amateur Radio Edition #1318 β Truncated 1-hour version
PODCAST: This Week in Amateur Radio Edition #1318 β Truncated 1-hour version
Via the ARRL: The K7RA Solar Update
PODCAST: This Week in Amateur Radio Edition #1318 β Full Version
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This Week in Amateur Radio
- PODCAST: This Week in Amateur Radio Edition #1318 β Truncated 1-hour version
PODCAST: This Week in Amateur Radio Edition #1318 β Truncated 1-hour version
FT8 is supposed to make DXing easy, why is it so hard?
FT8 has been a revolution. The technology has made DXing really easy. Or has it? I continue to be amazed at how much difficulty people have working DXpeditions on FT8.Β
Last year, there were DXpeditions to Bouvet (3Y0J), Crozet (FT8WW) and Sable Islands (CY0S). The most recent DXpedition to Glorioso Islands (FT4GL) has brought it all back to me.
Let's start off with a few observations on people trying to work these DXpeditions:
- Wrong Cycle - It's amazing the number of folks trying to work DX that are calling on the wrong cycle. FT8 has even and odd cycles. Even cycles start at 00 or 30 seconds, and odd cycles start on 15 and 45 seconds. You always call on the cycle the DX station is NOT transmitting. Indeed, if you double-click on a decode of the DX station, WSJT-X will set up the correct cycle. So how are people getting it wrong?
- Endless Calling - I've noticed some stations keep calling the DX after the DX station has QSYed or QRTed. A little bit of hopeful calling isn't unusual on Phone or CW, or even RTTY. But stations continue to call much later -- like an hour later, and they are still calling.
- Calling without Response - Some stations don't respond when the DX station calls them. They keep calling instead of advancing to the next step. This can get really bad. During the FT8WW expedition, I saw FT8WW keep responding to the same station for more than 10 minutes. Each response had a different signal report. This made it clear that FT8WW was heading this caller quite well, but the caller wasn't hearing FT8WW at all. Instead, that station took up a valuable response slot for 10 minutes -- denying perhaps 20-40 stations from working FT8WW.
- Confusing Fox/Hound (FH) and MSHV - Most DXpeditions using FT8 use either FH or MSHV in order to maximize the number of contacts they can make. It is easy to get confused with these two modes. They appear similar. Both allow for the DX station to transmit multiple FT8 carriers at the same time. FH imposes additional behavior to both the Fox and Hound ends of the contact. In particular, there are audio-frequency dependencies that FH enforces. But, it is perfectly possible to work a Fox station even if you are not in Hound mode. MSHV requires no special modes. And yet someone accused people of DQRM, calling FT4GL below 1000 Hz, when the DX was using MSHV, not FH.
FCC seeks comments on effects of May 2024 geomagnetic storm
The FCC recently released this public notice:
PUBLIC SAFETY AND HOMELAND SECURITY BUREAU SEEKS COMMENT ON THE IMPACTS OF THE MAY 2024 GEOMAGENTIC STORM ON THE U.S. COMMUNICATIONS SECTOR
PS Docket No. 24-161Comments Due: June 24, 2024
The Federal Communications Commissionβs Public Safety and Homeland Security Bureau (PSHSB or Bureau) seeks comment on any observed impacts to communications that resulted from the May 2024 severe geomagnetic storm. On Thursday, May 9, 2024, the National Weather Service Space Weather Prediction Center (SWPC) issued a severe (G4) Geomagnetic Storm Watch, forecasting a series of coronal mass ejections (CMEs) that merged with the Earthβs electromagnetic fields between May 7-11, 2024.1 On May 11, 2024, the storm reached extreme (G5) conditions, the first time this severity has been observed since 2003.2 According to the SWPC, CMEs are large expulsions of plasma and magnetic field from the Sunβs corona.3 Electromagnetic currents generated by CMEs, when merged with the Earthβs electromagnetic fields, may distort the propagation of radio frequency waves.
On May 11, 2024, the FCC High Frequency (HF) Direction Finding Center, which supports the public safety community and federal partners by locating interference to radio spectrum below 30 MHz, observed significant disturbance in the propagation of HF radio signals. This disturbance resulted in the disruption of voice and data communications passed over HF frequencies. To better understand the impacts of the geomagnetic storm on the U.S. communications sector, the Bureau is requesting information from communications service providers and the public regarding disruptions in communications between May 7 and 11, 2024, that it believes to be a result of the storm. The Bureau is encouraging commenters to provide any available evidence, particularly electromagnetic spectrum analyses, imagery, or chronological logs relating the stormβs impacts. Where possible, the Bureau asks that commenters include the description of the impacts; make and model of affected communications equipment, which could include transmitters, receivers, transceivers, switches, routers, amplifiers etc.; make, model, and type of affected antennae and their composition; frequencies affected; type and composition of cable adjoining communications equipment and the antennae, if applicable; duration of the impact; and any residual effects observed in the hours following restoration.
You can find the entire document, including footnotes and instructions on how to file a comment, at https://docs.fcc.gov/public/attachments/DA-24-493A1.pdf. It will be interesting to see a report on this after the comments are in.
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Copasetic Flow
- Low Slung Dipoles and How Project TouCans Reached California from US-5906 on a POTA by a Cliff
Low Slung Dipoles and How Project TouCans Reached California from US-5906 on a POTA by a Cliff
Β We got to camp a bit more in the middle of nowhere than we usually do while traveling across Utah last weekend. My partner found the Burr Trail Scenic Byway. I've looked for a route across southern Utah for the last several years, but had somehow missed this really nice, well-paved, little road.
We camped at the foot of an East-facing cliff, and the QSO map for the POTA reflected that fact pretty nicely:
Almost all of the QSOs and spots paid attention to that cliff face. And then, there was N0OI:
![](../themes/icons/grey.gif)
How? How had the signal cleared the cliff and skipped out to Perris, CA?
Using data from the Boulder, CO ionosonde, at the time Project TouCans was spotted in California, the F2 layer skip is modeled in the gif below. Note that it clears the mesa, (just barely.)
The other skip off to the Southeast was headed to the Cayman Islands. All of the skewing around is to convince myself that the the F2 path lines up with the path to the spotting station. You'll notice that there's a slight elevation offset that needs to be fixed.
More Notes on the POTA
As a final note, while I'm waiting for all the F2 data to come back, I've been trying to convince the gang that the F2-height datastream from the Boulder, CO ionosondeΒ
is in fact entered manually by a room of accountants not unlike those in John Wick, but to no avail. I guess they're just digital natives :)Β
Ah! And credits to where the ionosonde data actually is coming from
Reinisch, B. W., and I. A. Galkin, Global ionospheric radio observatory (GIRO), Earth, Planets, and Space, 63, 377-381, doi:10.5047/eps.2011.03.001, 2011.
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KM1NDY
- K-SARJ Technical Bulletin: Effect Of Near-Total Solar Eclipse On High Frequency Propagation Distances Using Cyclical Multiple Frequency Weak-Signal Propagation Reporter (WSPR) Transmissions
K-SARJ Technical Bulletin: Effect Of Near-Total Solar Eclipse On High Frequency Propagation Distances Using Cyclical Multiple Frequency Weak-Signal Propagation Reporter (WSPR) Transmissions
Doing a little hammy ham ham research during the solar eclipse at the Ole Farm-O-Laβ¦Welcome to the first Technical Bulletin of the KM1NDY β Secret Amateur Radio Journal.