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 3.7 megahertz, so 80 meters is marginal for NVIS. K index 2, quiet. No significant flares. Data from NOAA.

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 7:07 AM, sunset 6:50 PM, day length 11 hours 43 minutes. Moonset 2:56 PM at 304 degrees, west northwest. No moonrise today. Last quarter moon, 50 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 7:08 AM, 79 degrees high and 4 percent closer than average, a good time to listen for EME signals on 2 meters and up.

After sunset the D layer fades, and 160, 80, and 40 meters open for long distance contacts, while 15 through 10 meters close as the F layer weakens.

Amateur satellite passes for the next four hours. PO 101, FM, on a schedule: at 7:15 AM rising in the south southeast, 45 degrees. AO7, linear transponder: at 7:22 AM rising in the north northeast, 46 degrees, and at 9:15 AM rising in the north, 39 degrees. FO 29, linear transponder, on a schedule: at 7:59 AM rising in the south, 39 degrees. For the next pass, PO 101: uplink 437.5 megahertz with a 141.3 hertz tone, downlink 145.9. Frequencies and live status at amsat.org/status. Pass predictions at n2yo.com.

Satellite tip: the ISSAPRS digipeater is on 145.825 megahertz. Packet stations can send position reports through space.

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 2 hours ago: over Oakland, a duct at 700 to 1900 feet, good for 2 meters and up. A matching duct over Vandenberg suggests a path to Southern California. K6EEG's experimental tropo model, from NOAA data, for the next 12 hours: Ducting continues along the Bay Area coast, strongest around 5 PM, and the Southern California coast. Nothing toward Hawaii.

Tropo openings favor horizontal antennas. For CW, try 144.05 to 144.1 megahertz on 2 meters, and 432.1 on 70 centimeters.

Events. The California QSO Party, now under way, California stations in demand. IARU Region 1UHF/Microwaves Contest, now under way. IARU Region 2 Area GHFSSB Contest, now under way.

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.

Current weather conditions at San Francisco International Airport: Temperature 61 degrees Fahrenheit. Dew point 55 degrees Fahrenheit. Relative humidity 82 percent. Wind calm. Barometric pressure 29.87 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. Overnight: Partly cloudy, with a low around 58. Northwest wind around 1 miles per hour. Saturday: Sunny. High near 86, with temperatures falling to around 80 in the afternoon. North northwest wind 2 to 10 miles per hour. Saturday Night: Mostly clear, with a low around 63. West southwest wind 1 to 9 miles per hour.

Tide predictions for today at the San Francisco Embarcadero gauge. High tide at 7:11 AM, 4.4 feet. Low tide at 11:12 AM, 3.5 feet. High tide at 5:11 PM, 5.8 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 4 feet, moderate seas, dominant period 8 seconds, from the northwest. Wind at the buoy 2 knots from the northwest. Ocean water temperature 59 degrees Fahrenheit. San Francisco Bay water temperature 65 degrees Fahrenheit. Golden Gate currents: slack water at 7:54 AM, then maximum ebb 1.3 knots at 10:19 AM, then slack water at 1 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 7 parts per billion. Nitrogen dioxide is 13 parts per billion. For more information visit the Bay Area Air District or openaq.org on the web.

Sign up for your county's emergency alerts, such as Alert SF in San Francisco. Hams are often among the first to relay that information.

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 2.9, near South Lake Tahoe. No earthquakes of magnitude 6 or greater worldwide. Seismic data from earthquake.usgs.gov.

Repeater sites can go off the air after a major earthquake. Program simplex frequencies and know your local simplex plan.