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Today — 7 July 2024Main stream
Before yesterdayMain stream

Exploring Shortwave Radio Signals: A Peek into Non-Local Communications

✇AmateurRadio.com
By: Tomas NW7US
3 July 2024 at 02:17
Curious about what you can hear on shortwave ham radio? This video is a brief survey of the diverse world of communications on the shortwave spectrum. Expand your radio horizons and enhance your emergency communication preparedness by tuning in to the world of shortwave ham radio. If you’ve started delving into radio communications beyond local […]

Antipodal HF Radiation: Or How Did TouCans Talk to Nighttime Australia and Japan after Sunrise in CO?

✇Copasetic Flow
By: noreply@blogger.com (antigrav_kids KD0FNR)
17 June 2024 at 19:01

 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?

While the QSOs were awesome! How did they happen? I did a bit of research. 

Spoiler: I don't have an answer yet.

If you have ideas, I'd love help on this, please comment!

Dayside stations talking to nightside stations led me to sv1uy's page on chordal hop propagation which had a nice diagram



The rest of the notes from below followed from this diagram. I don't have answers yet, but here are my notes. I've been talking with the kids about radio occultation, refraction, and of course, the Gladych research project during all of this. I'm also using it to introduce trig which will layer in with the work the 11 and 9 year-olds, (Mota and Tawnse), are doing with fractions.

This mode, (numbered page 4 of Gold's thesis), is interesting because we had plenty of scattering. Notice the mountain peaks and ridges all round us below.



Chordal Modes Introduced with Villard

And we have our first reference to Villard, which included Okinawa, and therefore two different Gladychs, Michael's Project Smoke Puff article, and Stanislaw who was the architect for the Okinwa base in 1955.




And there's a bit of a Gladych aside here that's just too difficult to ignore. Apparently Stanislaw also few planes in World War II? I knew Michael did, but this is the first mention [pdf] I've seen of Stanislaw being a pilot


Carter Manny Jr. worked with Stanislaw. Here's his Chicago Tribune obituary.

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 get 

37.822754°N 107.717935°W -> 37.822754°N 72.282065°E



And our anitpodal is shown below near the 70 degrees East label.


Pretty excellent discussion of anitpodal points.

Conclusions for the moment

I don't know what propagation mode we had yet. We're going to pull some ionosonde data next to see if there was in fact a 'tilt' in the ionosphere at the time of the QSOs.


FT8 is supposed to make DXing easy, why is it so hard?

✇The Boring Ham Radio Part
By: AA4LR
1 June 2024 at 12:00

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. 

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.
What causes all these odd observations? I believe they all resolve to a single cause -- people are calling DX they cannot hear. That's right, people are calling DX stations they aren't decoding at all.

This is fundamentally wrong. I wrote about this years ago on how to bust a pileup. You cannot work DX if you cannot hear them. If you aren't decoding the DX station, stop calling. Yeah, that's hard, but your calls won't net you a contact, and you may be actively depriving someone who can hear the DX from making one. 

I think FT8 has made some people lazy. They hear some DX station is active on some frequency, probably through a spotting network. So they switch to that frequency, set their watchdog timers to an hour or more, and enable their transmitter. Then they go off and drink a few cool 807s while their computer works the DX for them.

Farfetched? No, it explains all the observations above.

Be a good FT8 operator -- don't call DX when you cannot decode them. Wait until you can decode them reliably, just about every cycle -- then start calling.


FCC seeks comments on effects of May 2024 geomagnetic storm

✇KB6NU's Ham Radio Blog
By: Dan KB6NU
29 May 2024 at 13:35

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. 24-161

Comments Due: June 24, 2024

The Federal Communications Commission’s 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 Earth’s 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 Sun’s corona.3 Electromagnetic currents generated by CMEs, when merged with the Earth’s 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 storm’s 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.

Low Slung Dipoles and How Project TouCans Reached California from US-5906 on a POTA by a Cliff

✇Copasetic Flow
By: noreply@blogger.com (antigrav_kids KD0FNR)
29 May 2024 at 13:23

 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:


Based on this overall map, I didn't think we could hit the West Coast because of this cliff face.


Almost all of the QSOs and spots paid attention to that cliff face. And then, there was N0OI:



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

I blew out my knee a bit sitting on the ground outside the tent for a three hour podcast interview on Friday night, consequently, the gang did most of the station set up including deploying Project TouCans in its dipole. Throughout that process, the family pup kept me company

When the gang were done, we had what, for Project TouCans, was a fairly typical antenna height of about five feet over the ground

One really interesting aspect of this POTA was that I didn't have the ability to Internet spot myself. Frankly, I wasn't sure it was going to work out at all, and for the longest time from about 00:02 GMT 24-05-27 till 13:50 GMT on the same day, it didn't. (Yes, I was asleep for most of that time with the rig turned off.) And then! Thanks—I think—to a few neighboring POTA stations, ops started to realize that TouCans was there! It may have also helped that my first QSO with WI5D was a bit of a rag chew.

Also, while hanging out on the cliff, the gang found an interesting mineral/quartz/mica/I don't know sample of rock. It was flat, broke easily, and contained pockets of crystals that were translucent. Any ideas what this might be?



For the moment, I'll leave you with this map of all the spots and QSOs for the POTA over the course of the evening, and into the next morning. Click play, then move the time slider all the way back to the left to see all the spots and QSOs with their associated F2 skips at once. Then, you can hit play to see how it all unfolded. (Keep in mind, the overnight nothingness is included in the map. You may want to skip over that.)



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 ionosonde 


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 :) 


Ah! And credits to where the ionosonde data actually is coming from

This was made possible with data collected by 





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