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 3.9 megahertz, so 80 meters is marginal for NVIS. K index 3, unsettled. No significant flares. Data from NOAA.

Coronal holes become more common as the cycle declines, bringing geomagnetic activity that repeats about every 27 days, one solar rotation. If conditions are disturbed today, watch for a repeat in about four weeks.

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, 51 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.

Meteor scatter is best in the hours before dawn, when Earth's leading side sweeps up more meteors.

Amateur satellite passes for the next four hours. RS 44, linear transponder, SSB and CW: at 6 AM rising in the north, 65 degrees, overhead. FO 29, linear transponder, on a schedule: at 6:14 AM rising in the southeast, 41 degrees, and at 7:59 AM rising in the south, 39 degrees. 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. For the next pass, RS 44: inverting linear transponder, uplink near 435.64 megahertz lower sideband, downlink near 145.965 upper sideband. 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 12 hours ago: over Oakland, a duct at 800 to 1200 feet, good for 70 centimeters 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 12 PM, and the Southern California coast, strongest around 6 AM. Nothing toward Hawaii.

Tropo openings favor horizontal antennas. Calling frequencies, upper sideband: 144.2 and 432.1 megahertz.

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.

Current weather conditions at San Francisco International Airport: Clear. Temperature 63 degrees Fahrenheit. Dew point 55 degrees Fahrenheit. Relative humidity 77 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. Know how long your backup power lasts. Test it under real load, not just with a meter.

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, slight seas, dominant period 8 seconds, from the northwest. Wind at the buoy 6 knots from the west. Ocean water temperature 59 degrees Fahrenheit. San Francisco Bay water temperature 66 degrees Fahrenheit. Golden Gate currents: maximum flood 1.9 knots at 4:26 AM, then slack water at 7:54 AM, then maximum ebb 1.3 knots at 10:19 AM.

If you feel a strong or long-lasting earthquake near the coast, move to high ground immediately. Don't wait for an official tsunami warning.

Air quality for field operations, from the Bay Area Air District's San Francisco Arkansas Street monitoring station. Fine particulate matter, PM2.5, is 5 micrograms per cubic meter, rated good. Ozone is 7 parts per billion. Nitrogen dioxide is 18 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 2.9, near South Lake Tahoe. No earthquakes of magnitude 6 or greater worldwide. Seismic data from earthquake.usgs.gov.

Secure radio equipment and shelving. A falling power supply or radio can take your station out of action at the moment it's needed most.