The ARRL runs a neato contest twice a year - the Frequency Measuring Test (FMT). The objective is to measure a transmission's unknown frequency as accurately as possible. There are 4 transmissions: 2 different geographical locations on 2 different bands (40m and 80m). The tests are run in the evening when the ionosphere is changing which adds an unpredictable element (doppler shift) to the results. Like any good “contest”, it's part skill and part luck!
The results are reported in accuracy windows:
Greater than 10 Hz doesn't get reported in a window but does get reported in your results listed by callsign.
You'll notice there's a method/soapbox with each callsign. If the contestant chooses, they can report their setup. Some of the setups consist of some amazing gear. My setup is basically my radio station with the addition of a GPS disciplined oscillator, namely the leo bodnar.
Here I'll note how I did my measurements so I can remember for future contests. I'll update this as I learn new things.
(EDIT: correct recommended subnet mask for 44. Of course it's no longer /8. It should be within either 44.0.0.0/9 or 44.128.0.0/10.)
The amprd package installs directly from the fedora repository. The configuration is straightforward, however getting firewalld and NetworkManager configured is a little tricky.
The amprd documentation refers to requiring the ipip_redirector for 4.13+ kernels. It's not required for the 6.8.9 kernel that comes with Fedora 40.
Note for the most part the commands require root so put sudo in front of the commands or become root with 'sudo -i'
I'm running Fedora on my Raspberry Pi 4b. I recently tried to upgrade the release from Fedora 38 to Fedora 39 Beta. After the system-upgrade reboot, I got pages of errors about certificates not yet being valid. I realized that my system clock was set about 10 days in the past, September 17th to be exact.
Since the upgrade reboot doesn't come up with a network connection, ntp doesn't set the time. But the time isn't January 1, 1970. So where was this 10-day-old time coming from?
What's often confusing about the FFT is that the transform seems to have numbers that are too big. Let's call this the “FFT scale factor” problem (it's a reasonable google search). The frequency domain seems to have much more energy (much higher values) than one might expect from the time-domain waveform from which it originated.
I just got back from a glorious trip to the British Virgin Islands (VP2V/N9DK/MM). Friends and I sailed among the islands: Norman, Cooper, Virgin Gorda, Anagata, Tortola, Mosquito.
When running a private network with DNS the network admin will set up .localdomain or .local as TLD for the private network.
But that's so many letters! Single letter TLDs are not assigned to anyone. While I'm pretty sure that's not an official rule, it would seem that they are specifically excluded. See the current list.
I've been a fan of dokuwiki for years and years, going back to my startup in 2005 when I used it to document our designs, usage, actions, etc. It's similar to the popular Mediawiki but offers better ACL. I've set it up multiple times in multiple ways, always a little concerned about security. I've had installed plugins with security flaws and it's just hard to stay on top. Most of the time I've deployed it for internal use inside a firewall.
Having worked at a startup for over 2 years that's heavily invested in docker, I've gotten to know docker really well. Not having had a website for quite a while, I finally decided to dip my toe in the water again using docker to contain my dokuwiki site.
QRP Quarterly has a column asking 10 questions of QRP operators. I offered mine for the April 2019 issue. I don't think there's any issue with publishing it here in advance: