Report

Space weather: solar flux 105, 10 below its 90-day average of 115. Maximum usable frequency 12 megahertz, measured by the Idaho Falls ionosonde via KC2G: long-distance paths open through 30 meters, 20 meters and up closed. Critical frequency 3.4 megahertz, so 80 meters is marginal for NVIS. K index 5, minor geomagnetic storm. No significant flares. Data from NOAA.

Geomagnetic storms can open aurora on 6 and 2 meters. Point north and listen for raspy, buzzy signals. We're in the declining phase of Solar Cycle 25, which peaked in October 2024. Sunspots and solar flux are trending down toward the next minimum, expected around 2030.

Sun and moon, Pacific Daylight Time: sunrise 7:08 AM, sunset 6:48 PM, day length 11 hours 40 minutes. Moonrise 12:27 AM at 58 degrees, east northeast; moonset 3:40 PM at 299 degrees, west northwest. Waning crescent, 38 percent lit. The Orionid meteor shower peaks Wednesday, October 21, a meteor scatter opportunity on 6 and 2 meters. Moonbounce: the moon peaks today at 8:07 AM, 76 degrees high and 3 percent closer than average, a good time to listen for EME signals on 2 meters and up.

VHF and UHF tropospheric enhancement is often strongest from sunset to early morning, when a nighttime temperature inversion forms.

Amateur satellite passes for the next four hours. AO7, linear transponder: at 8:14 AM rising in the north northeast, 86 degrees, overhead. AO 91, FM: at 9:49 AM rising in the south, 33 degrees. The ISS, FM crossband repeater, when active: at 10:30 AM rising in the southwest, 85 degrees, overhead. For the next pass, AO 91: uplink 435.25 megahertz with a 67 hertz tone, downlink 145.96. Frequencies and live status at amsat.org/status. Pass predictions at n2yo.com.

Satellite tip: satellite contacts count toward the ARRLVUCC satellite award for grid square chasers.

DX activity, via the cluster network and hamqsl.com. None spotted by West Coast stations right now. No aurora or 6 meter E-skip.

Tropospheric ducting, from balloon soundings 15 hours ago: Newer data is not yet available, and conditions may have changed. No ducting strong enough for amateur VHF or UHF bands over Oakland. K6EEG's experimental tropo forecast, based on NOAA atmospheric model data, for the next 12 hours. Bay Area coast, peaking around 7 PM: ducting expected on 70 centimeters, 80 percent; a chance of ducting on 2 meters, 35 percent. Southern California coast: a chance of ducting on 70 centimeters, 35 percent. Nothing toward Hawaii.

Events. The California QSO Party, now under way, California stations in demand. IARU Region 1UHF/Microwaves Contest, today. VHF-UHF FT8 Activity Contest, on Wednesday.

Club and community announcements. The SF Amateur Radio Club meets on the third Friday of each month, 7 PM at the Randall Museum. Visit sfarc.org for more details.

Check into a local net this week. Regular net practice is what makes emergency nets work. Test your go-kit monthly, and rotate batteries and supplies.

Current weather conditions at San Francisco International Airport: Temperature 66 degrees Fahrenheit. Dew point 57 degrees Fahrenheit. Relative humidity 73 percent. Wind calm. Barometric pressure 29.88 inches of mercury, normal. Visibility 10 miles.

Batteries and radios in parked cars degrade in heat. Keep go-kit batteries somewhere cool.

National Weather Service forecast. Today: Partly sunny. High near 85, with temperatures falling to around 77 in the afternoon. West northwest wind 1 to 12 miles per hour. Tonight: Mostly clear, with a low around 61. West wind 0 to 9 miles per hour. Monday: Sunny. High near 82, with temperatures falling to around 76 in the afternoon. West wind 0 to 10 miles per hour.

Tide predictions for today at the San Francisco Embarcadero gauge. Low tide at 12:34 AM, minus 0.1 feet. High tide at 8:16 AM, 4.7 feet. Low tide at 12:48 PM, 3.3 feet. High tide at 6:32 PM, 5.6 feet.

Ocean and bay conditions. No marine advisories in effect. From the San Francisco buoy, 18 nautical miles west of the Golden Gate: significant wave height 3 feet, slight seas, dominant period 8 seconds, from the northwest. Wind at the buoy 4 knots from the northwest. Ocean water temperature 60 degrees Fahrenheit. San Francisco Bay water temperature 66 degrees Fahrenheit. Golden Gate currents: slack water at 9:03 AM, then maximum ebb 1.5 knots at 11:39 AM, then slack water at 2:32 PM.

Air quality for field operations, from the Bay Area Air District's San Francisco Arkansas Street monitoring station. Fine particulate matter, PM2.5, is 7 micrograms per cubic meter, rated good. Ozone is 4 parts per billion. Nitrogen dioxide is 17 parts per billion. For more information visit the Bay Area Air District or openaq.org on the web.

Seismic awareness for emergency communicators: no Bay Area earthquakes of magnitude 2.5 or greater in the past 24 hours. Largest in California in the past 24 hours: magnitude 2.4, near Alum Rock. No earthquakes of magnitude 6 or greater worldwide. Seismic data from earthquake.usgs.gov.

Text, don't call. Text messages often get through when voice calls can't, and they keep lines open for emergency calls.