James Morris
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James Morris
jmorris
@kellylepo great story, which I'm assuming is getting very well known now
RE: https://astrodon.social/users/kellylepo/statuses/111881078696230611
RE: https://astrodon.social/users/kellylepo/statuses/111881078696230611
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James Morris
jmorris
@azonenberg @rgilton as a hobbyist, it's interesting to see concrete costs of professional level development. I just got 3 copies of a prototype board made by @oshpark for $8, including shipping.
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@stefanfendt good to know. I have seen main circuit RCDs for sale in the US, but they are in the hundreds of dollars and I don't know if or where they are required. No way a typical DIYer here is getting into that level of expense and expertise -- I assume any normal GFCI will trip on significant inductive or capacitative loads. People here expect such components to be very inexpensive.
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James Morris
jmorris
Edited 1 year ago
#electronics Pro Tip: do not apply -30V DC across the Vin+ and Vin- pins of INA169 current sensor chips. They don't like it.
Great high-side alternative to low-side digital current meters, fwiw:
https://www.adafruit.com/product/1164
Great high-side alternative to low-side digital current meters, fwiw:
https://www.adafruit.com/product/1164
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James Morris
jmorris
@g4dbn decent antenna setup
RE: https://mastodon.radio/users/g4dbn/statuses/111865540448497761
RE: https://mastodon.radio/users/g4dbn/statuses/111865540448497761
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James Morris
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#FOSDEM video recording of my first talk, "Soft Reboot" is already online: https://video.fosdem.org/2024/ub2252a/fosdem-2024-3282-soft-reboot-keep-your-containers-running-while-your-image-based-linux-host-gets-updated.av1.webm
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James Morris
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Linux Security Summit 🐧
LinuxSecSummit
🎟 There were some issues with the CfP closing in the wrong timezone: if you were unable to submit your proposal due to this, please use this secret link: https://sessionize.com/linux-security-summit-na-2024/?e=7aa558
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James Morris
jmorris
@penguin42 that’s why we just mentioned the one 3 phase I’d seen. I don’t understand it in general.
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@stefanfendt this is what I'm referring to, 480v with all 3 phases shorted together, https://www.youtube.com/watch?v=kXO9GJXF1kg
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@stefanfendt there are RCDs (GFCIs) in the US on many outlets, especially near water or outside.
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@HopelessDemigod yep, I have wondered about meteor scatter, which can provide 24/7 coverage in the range 500km-2300km if set up properly and also using burst mode comms. Very low bandwidth, but it doesn't depend on any fixed infrastructure, and is also resistant to nuclear effects. HF skip paths will be blocked by ionized air where detonations happen, but VHF will pass through.
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Also, re US vs .au, the way people talk about mains phases in the home can be confusing. Each 120v supply is called a phase, whereas if you have two 240v phases in .au, it's from a 3-phase feed. The 3-phase power I've seen in a person's garage here was 480v, which is getting well into catastrophic arc flash territory (search it up on youtube for an exciting time). People here very often do their own mains wiring mods, which is extremely unusual in Australia, I suspect in part because the default 240v is often lethal. Expect to die if you touch it.
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Using green wire for ground because the USA uses black for mains hot (active). I try and do this here when AC & DC are in the same enclosure. In Australia, brown is active and blue is neutral.
Also, fwiw, mains voltage here is supplied to homes as 240v, split into 120+120, neutral is centre tapped. It is not 110, 115, or whatever else you see: it’s 120v. Heavy duty appliances typically have 240v supplies, and some people run 240v to an outlet in the garage.
Also, fwiw, mains voltage here is supplied to homes as 240v, split into 120+120, neutral is centre tapped. It is not 110, 115, or whatever else you see: it’s 120v. Heavy duty appliances typically have 240v supplies, and some people run 240v to an outlet in the garage.
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James Morris
jmorris
Edited 1 year ago
Finished making a thing. This is a power supply for the 30W 10 GHz amplifier I’m working on. It should also be able to power the transverter, IF radio, & relays. I’m resisting the temptation to add an MCU and display. For now.
(Note: the 50 Hz label should say 60 Hz)
#hamradio #electronics #amateurradio #microwave #qro #sspa
(Note: the 50 Hz label should say 60 Hz)
#hamradio #electronics #amateurradio #microwave #qro #sspa
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Ok, I think I understand this a little more now. The horizontal bar in the waveguide is a thermal mass, which heats up in the presence of RF. The detector thermistor is attached to it (too small to see here), and it will closely follow the temperature of the bar. A bias current runs through the thermistor, and also the isolated compensation thermistor. The comp thermistor has its own thermal mass, which is the gold plated square, and a couple of rectangular blocks, which I assume were selected and pasted in by hand during construction, and this can be finely adjusted via the screw. Not sure exactly where the compensation thermistor is yet, and the circuit diagram shows a capacitor here somewhere. Could be both are in the white block, which looks like a modern SMD cap.
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