W8EMV - Whiskey Eight Echo Mike Victor

Field Day 2020 rules changes

Field Day is an annual event for amateur radio clubs around the country. The 2020 Field Day (June 27-28) will be different this year during the pandemic, and the ARRL has issued new rules that expand the role of home stations ("Class D", running on commercial power) in counting towards club goals.

Some local commentary on these changes is from Dan KB6NU who plans to operate Class 1B (battery powered) from his back deck.

As for me, I've already had a few QSOs on 2 meter simplex from my handheld from my home QTH and look forward to hearing some activity on the 2 meter band and the 70 cm band for that.

Skywarn monitor: W5US Wichita County TX 146.94

Monitoring the Wichita County TX Skywarn on the evening of Friday, May 22 2020. The Wichita Falls, TX area is under a Severe Thunderstorm Warning until 8 PM CDT, with 60 MPH wind gusts and tennis ball size hail possible. A report was called in at 2052 Eastern of ping-pong sized hail along I-44.

579 listeners are tracking this rebroadcast on Broadcastify as of 2112 Eastern. "This broadcast will be on the W5US 146.940 Skywarn Repeater used by trained spotters covering Wichita and Archer county in Texas. This repeater is active during all significant weather events that occur in the area."

Local broadcast TV coverage includes KAUZ Newschannel 6.

A 2019 Times Record News story has photos of Charlie W5GPO and his shack with radar and radios showing his net control station. W5GPO was net control for tonight's net up until 2116 Eastern.

In a 2016 blog from Jay W9LW there is discussion of a decision to close this net during severe weather, making it only available to members of the local ARES group. A further update regarding that controversy was a signal from the Texas ARES coordinator that all ARES nets in that state were to be conducted on frequencies open to all licensed amateurs. The concern was for storm chasers not local to the area pursuing tornadoes for fun and profit, and interrupting safety-related efforts. I was not able to determine the current status of this dispute, but there was no sign of any conflict on tonight's net.

A Terrible Tuesday in 1979 is the subject of an audiobook. "A recording of the actual radio transmissions of members of the Wichita County Amateur Radio Emergency Service, operating as SKYWARN Storm Spotters, during the large tornado that struck Wichita Falls, Texas, on April 10, 1979."

checklist for a refresh of my PiAware ADS-B feeder

I'm in the midst of downloading a fresh copy of PiAware to run as the ADS-B feeder on a Raspberry Pi 2. The Pi has a Flightaware branded RTL-SDR tuner stick and a Nooelec 1090 MHz antenna in a window facing to the east towards Detroit Metro Airport (KDTW). It currently also picks up good traffic to and from Ann Arbor Municipal Airport (KARB) and Willow Run Airport (KYIP).

A checklist for me to get the new system up and running.

1. Follow the instructions at Do you want to build your own FlightAware PiAware ADS-B Ground Station? for the basic software build, configuration settings, and to claim the device once it's live at Flightaware.

2. Follow the directions at Optional steps for advanced setup to configure login and password, SSH access, SD card filesystem size, and to confirm system status.

3. When running, configure your location with some precision so that MLAT will work.

4. Wait for daylight so there's actually some airplane traffic to calibrate against.

5. Create my usual admin account on systems, clean up SSH access so that it can be done with keys (this one is being stubborn), and make sure that all packages are up to date.

6. Install Tailscale for remote VPN access and set up DNS alias for the 'piaware' machine.

7. Add additional flight feeders to send flight data to other systems in addition to Flightaware.

My old system was running HypriotOS based on Debian Jessie (Debian 8) which is end of life this summer, so it's high time to redo it. I'm looking forward to that new SD card wiping out some accumulated configuration crud as well. The current machine had a 400+ day uptime streak but it's been a bit more flaky of late and the hope is that a new image will give a fresh start.

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Subsequent notes.

MLAT took a long time to sync, partially I'm sure due to the very low levels of traffic.

I'll do a separate post about additional flight feeders.

Public safety monitoring: Midland County (Michigan) 2020-05-19

A radio scanner feed of Midland County Public Safety is available through the Broadcastify service. The feed had 5000 listeners when I tuned in on the evening of Tuesday, May 20, 2020. The scanner feed covers police, fire, sheriff, EMS and regional State Police.

Several dams along the Tittabawassee River upstream of Midland Michigan failed on Tuesday, leaving impoundment lakes empty and causing the river to rise above historic high water levels. The City of Midland is evacuating about 10,000 residents, and parts of US-10 are closed through the area.

Additional news sources to follow what's going on. From here in Ann Arbor I can only listen to the scanner.

• Midland Daily News: "Downtown Midland prepares for deluge as Tittabawassee River floods"
• NBC 25 News: "Edenville and Sanford dams fail leading to evacuations"
• WNEM: "BREAKING: Residents in Freeland, Tittabawassee Twp evacuating due to dam failure"
• MLive Saginaw/Bay City: "Pilot captures aerial footage of roaring water as Edenville Dam bursts in Midland County"
• Bridge Magazine: "Mid-Michigan dam that failed was cited for years for safety violations"

For traffic and road updates, see the Twitter feed for @MDOT_Bay which has up to the minute road closures.

Edenville Dam: a major dam collapse is an early account of the Edenville Dam failure in Dave Petley's "Landslide Blog", published by the AGU. "At the moment the cause / mechanism of the failure is not clear." There are good photos and video of that dam failure there.

The biggest environmental concern is to the Dow Chemical facilities adjacent to the river.

Tittabawasee Jane is a song by Jay Stielstra about the river that flows through Midland.

"She made napalm, some kind of bomb, I wasn't too political then".

W8UM U of Michigan Amateur Radio Club net, 2020-05-17

Thirteen stations, 26 minutes on the Sunday night 8:00 p.m. net on 145.23- and W8UM/R on Echolink.

One nice thing about this net is that it goes pretty quickly to leave time for another net (ARPSC) that happens at 8:30 p.m. Lots of brief reports tonight that made you want to learn more.

The beaches are reopening in Hawaii. Bird watching in Ann Arbor is better than usual with blue jays and orioles in evidence. Yesterday was good for mountain bike riding. Local rhubarb is in the market. The Blue Angels did a very brief flyover. The trees are getting green. Getting ready for what will be an unusual Field Day. A power supply needed repair or replacement, but worked OK on low power. New FT8 software has a release candidate, which works great so far.

I joke with my family that this is the "fix your radio hour", and that was in evidence as it is every time - it wouldn't be a proper net without someone overcoming a temporary obstacle.

I listened on my Baofeng UV-5R and then shifted over to the setup I have with a Pi 4 running Ubuntu 20.04 and rtl_tcp, feeding Gqrx on my MacBook Air. The rtl_tcp setup introduces a few seconds of software-defined delay compared to the radio hardware, and it's nice to watch the spectrum go by as you listen.

Thanks to Pat WA4DSR for taking net control.

Ball Smacker Radio - pirate radio on 6960

Thanks to an ID by Matt Blaze, I picked up Ball Smacker Radio broadcasting from "somewhere in the Northeast" playing classic rock on 6960 KHz.

Adjacent interference sounded like some kind of radar signal.

"The 20": locating a Seattle FM radio station

The mystery of "The 20", a Seattle FM radio station with a playlist of 20 songs in an endless loop.

Nathan Barnes has the playlist, all tunes from 1958 (Eddie Cochran's Summertime Blues) to 1977 (The Commodores w/Lionel Ritchie, Easy Like Sunday Morning). The approximate transmitter location is not yet determined, but one listener has a Kerberos SDR with 4 channels of RTL-SDR which should readily help direction finding.

The more general problem of locating a rogue transmitter is "fox hunting", and one tool for that is using a directional antenna with a null that helps you zero in on which way the signal is coming from.

rtl_tcp and Tailscale on a Pi 4 with Ubuntu 20.04 LTS

Proof of work below, showing GQRX on a MacBook Air with WCBN-FM 88.3 tuned in, with WEMU-FM 89.1 adjacent, via a Tailscale VPN connection to an rtl-sdr running on a Pi 4 under Ubuntu 20.04 LTS arm64.

The antenna I'm using is my 2 meter antenna, which should usually mean that FM signals are unwanted noise - for now they are ok.

On the Pi 4 one Tailscale process is pinned at about 70% CPU, so it's working hard to keep up the VPN stream. I am not noticing any lag or dropouts, though, and the actual rtl_tcp process that's decoding the radio is not so busy. When I switch over from Tailscale to normal unencrypted streams, the CPU quiets way down. I have a feeling there's more to be squeezed out of the arm64 cores on the Pi 4.

librtlsdr and zero-copy support on Ubuntu 20.04 + arm64 + Pi 4

The patch at 81833a1c is necessary on an arm64 system running librtlsdr-dev, otherwise you get the error

Reading samples in async mode... Allocating 15 zero-copy buffers Killed

This is fixed in Debian Sid in a version labelled 0.6.0-3. Unfortunately, there is also a Ubuntu 20.04 version of the library also labelled 0.6.0-3 which has the bug - noted on Launchpad as 1876624.

The workaround I did was to install the .deb file from Sid on top of my Ubuntu 20.04 installation, which I hope to undo as soon as I can. It also worked to build that library from source.

Other than that, my experience with Ubuntu 20.04 on the Pi 4 running arm64 has been just fine. I'm looking forward to updating the rest of my Pi menagerie, some of which is stuck on old Debian Jessie.