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Michael Katzmann🐈
@vk2bea@mastodon.radio
mastodon 4.7.3Electronics engineer & radio amateur - NV3Z, VK2BEA & G4NYV.
ex ATN7 Sydney / Broadcast Sports Tech. / Library of Congress
136 Followers
76 Following
24 Posts
Joined November 05, 2022
PGP/GPG Public Key:
Amateur Radio:
NV3Z / VK2BEA / G4NYV / ex AAR3VK
Github:
Maidenhead Grid Square:
FM18lx
Tuesday tip.....
How to clean the center pin socket of a BNC or N connector...
Use a dental soft pick and contact cleaner (or IPA).
Its cheap, fits perfectly and is non abrasive.
Replying to
@kenshirriff Do you know what accuracy it could achieve?
I saw an interview with WW2 navigator who said he could only determine the location of the airfield to within 5 miles (with a sextant) .. in a bomber over Germany, he was lucky to even find the right town!
Replying to
@kenshirriff .. so about 11 km at 34 degrees north.
I guess with a 10 megaton bomb, it's good enough. If Dr Strangelove is anything to go by, the final bombing run used radar 😸
There is a pivotal scene in the 1959 movie "On the Beach", where the submarine crew investigates the source of a Morse code transmission emanating from a post apocalyptic San Diego.
On seeing this again today, I realized that the key is the same model as the one I have; a P.M.G. (Postmaster General's Dept) 1940 WT #2
The movie was shot in Melbourne, so these keys would have been even more common then than they were when I learnt Morse in the 70's.
Replying to
@Natasha_Jay@tech.lgbt There are some amazing color photographs (circa 1911) from Sergei Mikhailovich Prokudin-Gorskii at the Library of Congress.
These were made using three RGB plates sequentially.
https://www.loc.gov/exhibits/empire/gorskii.html
Removal of the 15th Street bike lane stopped by the court.
https://ecf.dcd.uscourts.gov/cgi-bin/show_public_doc?2026cv0988-33
…the Removal Project may not and will not proceed on April 23, 2026.
Replying to
@fedora@fosstodon.org FWIW...I had great difficulty in fixing this.
The Linux/Fedora firmware updating mechanism kept failing.
Eventually I resorted to the "Restore Factory Keys" function in the BIOS (Lenovo desktop machine). After that the Linux update worked.
@samlitzinger@journa.host mmm .. maybe I'll suggest that my friend de-Tesla his car (Tesla is the SI unit of magnetic flux - Gauss is the older MKS unit 😉 )
@samlitzinger@journa.host I' think it's a bulk tape eraser. (but that is just an educated guess!)
Upon checking a large electrolytic capacitor this morning, I was disappointed that it showed an ESR (25 mΩ) higher than spec (6mΩ)
Upon further reflection I realized that although I had calibrated the instrument, I neglected to include the connecting wires.
Sometimes every milliohm matters!
It's not just an electrolytic - its an 622D 'Extralytic'!
(big thanks to @bitsavers@oldbytes.space for preserving the Sprague catalog!)
Replying to
@Ea5iyl@mastodon.radio The 23cm amateur band is assigned on a secondary allocation. We are not to interfere with the primary user (navigation services).
GNSS signals are wide-band direct sequence spread spectrum. This protects them somewhat from interference from narrow band signals; however, low power or poorly designed receivers are likely subject to overload from a strong nearby transmission which may adversely effect performance.
The official White House Android app has a cookie/paywall bypass injector, tracks your GPS every 4.5 minutes, and loads JavaScript from some guy's GitHub Pages.
Replying to
@samlitzinger@journa.host I remember a colleague who lamented that the real time commentary of the Space Shuttle Challenger disaster lacked the emotion of Herb Morrison's coverage of the demise of the Hindenburg. Without pictures if fell to the radio man to convey so much more.
Replying to
The Farrelly Brothers - I've Been Everywhere (1974)
Oh, great.. another headache.
Iran war disrupts the circuit board supply chain, raises costs for tech firms
Replying to
@samlitzinger Back in the '70s Australian author Alexander Buzo ran an annual award - "The Australian Indoor Tautology Pennant". If it still ran, this would, no doubt, be a nominee.
Replying to
@Ea5iyl@mastodon.radio There is also this document: https://www.itu.int/dms_pubrec/itu-r/rec/m/R-REC-M.2164-0-202311-I!!PDF-E.pdf
Guidance on technical and operational measures for the use of the frequency band 1 240-1 300 MHz by the amateur and amateur-satellite service in order to protect the radionavigation-satellite service (space-to-Earth)
Replying to
@Sheril@mastodon.social Richard Feynman - "It doesn't matter how beautiful your theory is, it doesn't matter how smart you are. If it doesn't agree with experiment, it's wrong."