DX’ing around local sunrise and sunset can be a highly rewarding endeavor for radio enthusiasts, offering opportunities to log new stations. To make the most of this, there are several strategies to explore. One key tool for this is a set of sunrise/sunset maps, which can be purchased from the NRC Publications Center. These maps provide the times at which radio stations transition from their authorized daytime facilities to their nighttime facilities, or sign off entirely, depending on whether they operate as daytimers. The maps group stations into zones based on their local sunrise and sunset times, which are important for understanding signal propagation patterns.
However, it’s important to note that there are exceptions to these general patterns. Some stations are authorized to use special facilities during Critical Hours (CH), Canadian Restricted (CR), Pre-Sunrise Authority (PSA), or Post-Sunset Authority (PSSA), each with unique operational conditions. Understanding these nuances is crucial, and for this, you’ll need to familiarize yourself with the terminology and operational codes listed in resources like the NRC Domestic Log.
Understanding Propagation: How Sunrise & Sunset Affect DX’ing
Due to the Earth’s rotation, sunrise and sunset occur first on the eastern side of the continent, and gradually progress westward. This westward movement means that DX’ers located along the coasts will experience different conditions compared to those in the middle of the continent. Coastal DX’ers may have certain directional advantages, while those further inland will have the opportunity to track the changes in propagation as sunrise or sunset progresses.
During the day, medium-wave propagation mainly relies on groundwave signals, which limit the range of reception, especially during the summer months. At night, skywave propagation takes over, where radio signals are reflected by the ionosphere, allowing for much greater distances to be covered. As sunrise approaches, signals from the east begin to fade, and similarly, as sunset approaches, signals from the west become stronger.
The direction of propagation is not always simply “east vs. west.” Due to the Earth’s orbit, sunrise and sunset times shift throughout the year, meaning that the propagation patterns also vary monthly, which adds a layer of complexity and excitement to the hobby.
Maximizing DX’ing Potential
Once you have a solid understanding of the maps and their shifting patterns, you can begin identifying the frequencies to focus on. While it may be tempting to avoid strong local frequencies, don’t dismiss them too quickly. Often, sunrise and sunset DX’ing offers the best opportunity to hear stations that are otherwise masked by local interference. In many cases, a gain or directional antenna may be necessary to hear these signals clearly, but even without specialized equipment, stations may still be audible under favorable conditions.
Your target list should be divided into sunrise and sunset categories. The key is to focus on frequencies that are not dominated by strong local stations, and where you can hear multiple stations even at night. You should also be mindful of frequencies adjacent to troublesome stations that might cause interference.
Creating an effective target list today is more complex than it was 20 years ago due to the increase in full-time operations, PSA’s, and PSSA’s, where once only daytime stations existed. Some DX’ers fondly remember a time when they could hear stations from across the country on frequencies like 1580 kHz and 1570 kHz. Now, with full-time stations on most frequencies and the increase in stations operating well past their daytime hours, compiling a target list has become a more intricate task.
Crafting Your Target List
To start, select frequencies where you don’t have strong local stations, and where you can realistically hear more than one station. Avoid frequencies near your most troublesome interference sources, and focus on stations with sunrise or sunset times that are within about 30 minutes of your location. Stations within a 300-400 mile radius are ideal targets.
Review your list of potential targets and remove any stations likely to be overshadowed by stronger regional stations on the same frequency. You can expand your list later as you become more familiar with how the propagation changes.
To optimize your DX’ing potential, you will need to review your target stations along with any potential co-channel interference. You can use your maps for this, photocopying them and plotting your target stations on them. By using a numbering system, you can identify each station and keep track of your DX progress month by month.
Tracking and Adjusting for Conditions
Remember that conditions on specific frequencies can vary greatly from day to day and month to month. Some stations may be challenging to hear consistently, but with persistence, you may eventually log them. Some DX opportunities may arise unexpectedly, such as when another station goes off-air or your target station stays on with daytime facilities.
As you continue to DX at sunrise and sunset, you will begin to notice patterns in your reception. For instance, during the Fall, when days shorten, your best receptions may occur toward the end of the month, when daylight is shortest compared to the monthly average. After the Winter Solstice, the best DX opportunities often occur at the beginning of the month for the same reason. You’ll also find that stations located near the eastern zone boundary often appear stronger at sunset, and stations near the western boundary may be more prominent at sunrise.
In summary, sunrise and sunset DX’ing offers a dynamic and rewarding experience for radio enthusiasts. By understanding the propagation patterns, using the right tools like sunrise/sunset maps, and crafting a thoughtful target list, you can significantly expand your radio loggings. With time, you’ll develop a deeper understanding of how the Earth’s rotation and the changing seasons influence the radio waves, and you’ll improve your DX skills month by month.