Propagation Study Paths

1. California coastal range mountains that obstruct the initial 80 mile radio path under study include the Sugarloaf Ridge immediately east of Santa Rosa, California and the Berryessa Blue Ridge Mountain area, both with elevations ranging from 1,600 to 2,000 feet.

2. WSPR Propagation study paths. W7PUA-N6KOG 482 miles from NW Oregon to the central California valley. N6GN/K6PZB-KC6KGE 292 miles over coastal range summits. N6KOG-N3IZN 385 miles through central California valley and over San Bernardino Mountains. Interactive map link Google Earth KML file

View 2 meter WSPR Propagation Study in a larger map

3. The Radio Mobile Online application produced this combined coverage map for the West Coast 2 meter WSPR study group stations. At least one of our stations should be heard on 144.4905 MHz at locations from Southwest Washington state through California from Redding to the Grapevine and to San Diego. The expected signal to noise ratio is greater than -20 dB in the yellow areas and less than -20 dB in the orange areas.

4. Northern California Stations in 144 MHz WSPR Propagation Study. The path distances between Sacramento (KP4MD-WW8L), Santa Rosa (K6PZB-N6GN) and Milpitas (KI6STW) are similar. There are no apparent high elevations obstructing the path from Santa Rosa to Milpitas. Mt. Allison (Elev. 2664 ft) in the Monument Peak Ridge is 3 miles away from Milpitas and directly obstructs the path to Sacramento. The Sugarloaf Ridge and Blue Ridge-Berryessa areas average 1800-2000 ft elevation and obstruct the path from Santa Rosa to Sacramento.

5. 6 June 2012 - N6GN WSPR signals received at KP4MD. The steep diagonal traces on the waterfall are reflected signals from passing aircraft subject to Doppler shift.1 N6GN has observed that Doppler reflections near the signal frequency for about 20% of each two minute transmission window often cause WSPR signal decoding failure.

6. Time lapse screen captures of contacts among 144 MHz WSPR propagation study stations. All spot reports consisting of time, signal to noise ratio, time segment shift, frequency and drift received at the study stations are uploaded to a database at