Tag Archives: amateur radio

Mapping the Eclipse for a Citizen Science Project

Map of the continental United States showing the amateur radio grids and path of the eclipse.  Image credit: Bill Mitchell (CC-BY).
Map of the continental United States showing the amateur radio grids and path of the eclipse. Image credit: Bill Mitchell (CC-BY).

During the solar eclipse next week, I will be at the Science Museum of Minnesota with a citizen science project studying the effects of the eclipse on radio propagation. While there are many radio-related projects going on—the most accessible being a study of AM radio reception—I will be using amateur radio to make contacts and provide reception reports during the eclipse. One of the important pieces of information that will be exchanged with other amateur stations is a “grid”, which is a shorthand for rough latitude and longitude.

Amateur radio grids are 2° longitude by 1° latitude, and represented with pairs of letters and numbers. For instance, the Science Museum of Minnesota is located in EN34. Fields (20°x10°) are designated with letters, and increase from -180 longitude and -90 latitude (AA) to 160 longitude and 80 latitude (RR). Fields are further subdivided into grids using numbers, which increase from 00 at the southwest corner to 99 at the northeast. Looking again at our example, the first character, E, indicates a location between 100° and 80° W longitude, and N indicates a location between 40° and 50° N latitude. The numbers provide further refinement on that range. The 3 means the longitude is between 6° and 8° east of the west edge of the field (i.e. 94°–92° W), and the 4 after it means the latitude is 4°–5° north of the south edge of the field (i.e. 44°–45° N). Further letters (A-X) and numbers can be used to specify locations more precisely in a similar fashion. Longitude is always indicated first, and increases west-to-east; latitude is indicated second, increasing south-to-north.

For the event, I want to have a map of the continental US and southern Canada with the grids outlined on it. During the event as we hear which grid other stations are in, we can mark their location on the map. Unfortunately, I was not able to find a map that I wanted to use for this purpose, so I decided to make my own with QGIS.

For my eclipse map, I needed to gather a few datasets. First and foremost, I needed a US state map. Canadian provinces were also a high priority. Once I had those, I was still missing Mexico and other North American areas, so I found a world map as well. That covered the basics, but as long as I’m making a special map for the eclipse, I wanted to have the path of totality, which I found from NASA. I unzipped each of those files into a folder for my eclipse grid map project.

In QGIS, I loaded all the datasets (vectors). The Canadian provinces were in a different projection, so I saved (converted) it to the projection I wanted (EPSG:4269), which is a simple latitude-longitude projection. I found that the Canadian provinces included detailed coastlines and islands, so I simplified it (Vector | Geometry Tools | Simplify Geometry) using a tolerance of 0.01 or something like that. The islands cleaned up a little, but the overall shapes didn’t change much.

With the datasets loaded, I needed to make my field and grid boundaries. Using the grid tool (Vector | Research Tools | Vector Grid) I created the field grid (xmin=-180, xmax=180, ymin=-90, ymax=90, parameter x=20, parameter y=10) and the fine grid (same except parameter x=2, parameter y=1).

I looked up the coordinates for the Science Museum of Minnesota, and put them into a CSV text file. By loading in that CSV file, I put a star on the map where I will be located.

From that point, it was just a matter of adjusting colors and display properties. I gave reasonable, light colors to the US and Canada, and thickened the borders for the US states. I used a dashed line for the field lines, and a lighter grey dotted line for the smaller grids. The eclipse path I made a partially-transparent grey.

That’s about all there was to it! In the print composer I added in some of the labels for a few grids to help demonstrate the letter/number scheme.

Results (PDF): 8.5″x11″, 11″x17″.

Ionospheric Science and Amateur Radio from Heard Island

Aurora Australis seen from the International Space Station as it flew over Heard Island on September 7, 2015.  Image credit: NASA (public domain).
Aurora Australis seen from the International Space Station as it flew over Heard Island on September 7, 2015. Image credit: NASA (public domain).

High above Earth’s surface, roughly 60–1000 km up, is an intriguing part of Earth’s upper atmosphere called the ionosphere. High-energy light (mostly ultraviolet and X-rays) causes electrons to be stripped away from gas molecules and neutral atoms, forming ions (and free electrons). The incoming light is most intense at the upper edge of the atmosphere (before it is absorbed), but the density of atoms and molecules is higher at lower altitudes (with atmospheric density highest at the Earth’s surface), leading to a peak in ionization in an intermediate region. Much of the interesting action in the ionosphere is in the regions between 60–300 km up, where the electron density is highest (though still very low compared to sea level).[1]

Under many conditions, radio waves between 160 m and 10 m (with frequencies of 1.8–30 MHz) can be refracted by the ionosphere, enabling wireless communication around the globe. This long-distance propagation is, at least to me, a wondrous phenomenon.

Effectively, there is a low-frequency limit below which the radio waves are strongly absorbed by the atmosphere. At a sufficiently high frequency, the radio waves will not refract back down to Earth, and will simply pass into space. However, in the Goldilocks zone between those two frequencies (the lowest usable frequency and maximum usable frequency), propagation can occur.

Schematic cartoon of ionospheric propagation.  Image credit: NOAA (public domain).
Schematic cartoon of ionospheric propagation. Image credit: NOAA (public domain).

With the amount and intensity of sunlight reaching the ionosphere changing throughout the course of the day, year, and solar cycle, the maximum and lowest usable frequencies will change as well. Additionally, since not all of the globe is illuminated at the same time, these limiting frequencies will vary spatially. Consequently, the maximum usable frequency in one location may be below the lowest usable frequency somewhere else, and no radio contact can be made between those points at that time.

Scattered around the world are many, many radio stations operated by licensed amateurs (sometimes also called hams; etymology unclear).[2] One aspect of the hobby which many amateurs enjoy is making contact with amateurs in other countries around the world. Just like birders have a life list of the species of birds they have seen, amateur radio operators often keep a list of other countries and territories they have contacted, splitting this list further by frequency and operating mode (Morse code, voice, or digital). Currently, there are 340 recognized entities worldwide.[3] Of those 340, many are small reefs, islands, or archipelagos, and may not have any permanent population—such as Heard Island, making them very rare. The last time Heard Island was heard on amateur radio was in 1997. It’s presently the longest-inactive of the 340 entities and ranks around #5 on most-wanted lists. Many amateurs have been looking forward to this expedition for a long time, and have been very generous in supporting it financially.

On Heard Island, our team will put up several amateur radio antennas at Atlas Cove, and set up approximately 6 radios. We will then make contacts with as many stations as we can on the various amateur frequencies, in a combination of voice, Morse code, and digital modes, using the callsign VKØEK. Contacts are extremely brief which helps keep the throughput high, giving more stations a new entity for their list and us a more statistically significant sampling of the ionospheric conditions.

Here’s how a voice contact might proceed:

[VKØEK]: Victor kilo zero echo kilo, listening up
[Din of thousands of stations calling with their callsigns]
[VKØEK]: Kilo zero bravo bravo charlie, five nine4
[KØBBC]: Five nine, thanks
[VKØEK]: Thank you

It’s not a long, drawn-out conversation, but is enough to be logged on both ends as having happened. Under ideal circumstances, within a minute or two, that contact will be shown on a near-real-time map of contacts from Heard Island. With luck and the cooperation of stations around the world, we should be able to log >100,000 contacts over the three-week period and gather some very interesting data about which frequencies work to which places at which times.

Simulated near-real-time map of contacts with Heard Island, shown on the DXA3 website.  QSO is radio shorthand for contact.  Numbers under Currently Working heading are approximate wavelengths in meters, corresponding to the amateur radio allocations.
Simulated near-real-time map of contacts with Heard Island, shown on the DXA3 website. QSO is radio shorthand for contact. Numbers under Currently Working heading are approximate wavelengths in meters, corresponding to the amateur radio allocations.

Of course, one other advantage of the amateur radio operation is that it is yet another means of communication in the case of an emergency. While we hope that no emergency communications are needed of any type, and we have a number of satellite communications options, amateur radio provides one more level of redundancy, and has been shown to be reliable in places where little or no infrastructure exists (e.g. following major earthquakes, hurricanes, etc.).

The ionosphere does amazing things, and our amateur radio operation will both yield data on the ionosphere as well as make many thousands of amateur radio operators happy that they were able to contact a new entity.

*** Notes and References ***

[1] For a point of reference, airplanes generally fly at a height of 10–13 km, the highest jet aircraft flight record is 37.6 km, and the International Space Station is at a height of roughly 340 km; even high-altitude weather balloons and rarely exceed 40 km.

Features of Earth's atmosphere.  Image credit: NOAA (public domain).
Features of Earth’s atmosphere. Image credit: NOAA (public domain).

[2] In the US, getting an entry-level amateur radio license requires passing a 35-question multiple-choice test on terminology, regulations, basic electronic theory, and operating practices, and is roughly equivalent to a written driver’s exam. Knowledge of Morse code is not required. For more on US licensing, see this page.

[3] Islands and outlying territories beyond certain distances from the main entity are considered separate, so Hawaii, Alaska, Puerto Rico, and the US Virgin Islands all count as separate entities even though they are US states, territories, or possessions. The gritty details on criteria for listing as separate entities is found in section 2 here.

[4] “Five nine” is a signal report, meaning “I hear you loud and clear”.