SARC 6m Beacon

Beaconing on the Magic Band

Call Sign: VE7SAR/B Location: CN89oc Band: 6M Mode: CW Frequency: 50.070 MHz Power: 2W

The Surrey Amateur Radio Communications Society (SARC) continues to expand its boundaries above 30 MHz with the successful deployment of a 6m beacon, VE7SAR/B, operating on 50.070 MHz. This initiative, part of a broader effort to promote activity on underutilized bands, builds on the success of the club's earlier 10 GHz and 24 GHz beacon projects.

The driving force behind the 6m beacon has been Dino Gueorguiev, VE7NX, whose leadership, technical expertise, and determination were instrumental in bringing this project to life. Working with Scott Charles, VA7SC and John VA7XB, Dino oversaw the beacon's design, construction, and deployment, ensuring it became a reliable tool for monitoring propagation and encouraging 6m activity among local and regional amateur radio operators.

Technical Details and Design

The 6m beacon project began with the goal of creating a signal that most club members could easily monitor, given that 6m is often called the "magic band" due to its fascinating propagation characteristics. Unlike most amateur radio beacons , where components are generally available off the shelf, the SARC 6m beacon required more creative problem-solving.

At the heart of the beacon is an Arduino Nano microcontroller paired with an Si5351 clock chip. The printed circuit board (PCB) was designed by Bert, VE2ZAZ, and sourced from Oregon State. The system relies on a 10 MHz oven-controlled crystal oscillator (OCXO), following a design by Hugh, VA3TO, to provide a stable reference frequency.

Dino, VE7NX, personally wrote the software code for the Arduino, integrating all components to generate the precise 50.070 MHz CW signal. For the initial amplifier stage, Dino repurposed a 3W amplifier brick sourced from his own collection and built a custom low-pass filter to clean up the signal before transmission. The antenna, an omnidirectional Moxon-type horizontal design, was procured online by John, VA7XB, ensuring wide area coverage without the need for significant elevation.

Challenges and Overcoming Setbacks

The initial installation of the beacon at SARC's Operations & Training Centre (OTC) in South Surrey went smoothly and operated successfully during testing. However, the team soon faced an unexpected challenge. When a nearby HF contest began, a 1 kW amplifier operating on 40m—just above the 6m antenna—generated significant harmonics that overwhelmed the modest 3W amplifier, leading to irreversible damage.

Stepping in to address this critical issue, Les, VA7OM, designed and built a robust replacement amplifier. Importantly, this new amplifier incorporated a bandpass filter with strong rejection on the 40m band, safeguarding the beacon from future interference. With the improved amplifier installed, the beacon has since operated continuously and reliably.

Community Impact

The VE7SAR/B beacon serves as a valuable resource for both the SARC membership and the wider amateur radio community. Operators from across the Lower Mainland of British Columbia, Vancouver Island, and even as far south as Seattle, Washington, have reported hearing the beacon. Its continuous CW signal provides an important indicator of propagation conditions on 6m, a band known for openings that can span vast distances when conditions align.

Dino's leadership and hands-on involvement have been central to the beacon's success. His ability to source components, integrate hardware and software, and mobilize fellow club members exemplifies the spirit of amateur radio experimentation and collaboration.

Listen In

For those interested, the VE7SAR/B beacon can be monitored on 50.070 MHz in CW mode. We invite all operators to tune in, report receptions, and join us in exploring the magic of the 6m band. If you hear our 6m beacon, please let us know at beacons@ve7sar.net.

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