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“RF Seismograph” Improved to Better Reflect Band Activity


The Scanning RF Seismograph, a real-time HF propagation-monitoring tool developed by the MDSR Team and Alex Schwarz, VE7DXW, now can show both combined band noise and activity and just band activity. The RF Seismograph, which covers 80, 40, 30, 20, 15, and 10 meters, is a project of the North Shore Amateur Radio Club (NSARC).

“We were able to extract signals from the noise and display the results in gray scale vertical lines — white is best propagation,” Schwarz said. “This separate display does not indicate changes in noise level.”

The site is in Lynn Valley (CN89li), North Vancouver, British Columbia, at 500 feet ASL. A transceiver connected to an omnidirectional multiband antenna monitors JT-65 frequencies on six HF bands (for 8 seconds each, repeating the scan every 52 seconds). Recorders monitor signals and background noise on a given band and display the results in six color-differentiated (one color per band), long-duration graphs covering 6 hours of scans. Vertical movement of the primary graph traces is caused by changes in noise level and by the reflection of noise off the D Layer off the ionosphere, Schwarz explained.

When signals are present on a band, white vertical bars, color-coded by band below the main graph, indicate propagation based on the degree of activity. The web link is updated every 10 minutes.

Schwarz said the RF Seismograph also now can create a log file of events by matching propagation (white lines) with the recorded band and signal.

The MDSR Team is hoping to develop a notification system that sends an e-mail when a band appears to be open. “The idea is that, once you have set up the software, you could have maybe up to 100 e-mail addresses that will receive notification,” he said. Schwarz believes this would get more people on the air, “because they are aware of the band conditions.”

Schwarz said the RF Seismograph software confirms that solar flux is not the only indicator of HF propagation. “Even during times when the sun's flux flatlines, decent propagation is possible,” he said. “Another finding is that propagation is very local, and it has to be measured at the amateur station’s location best results.”

For more information, contact Alex Schwarz, VE7DXW.