zuck can’t be in practical terms fired

vapor pressure of liquid carbon dioxide at whatever temperature storage tanks happen to be. wiki tells me it’s 60 atm at 22C and 40 atm at 6C, so not that much in grand scheme of things

the trick is that in high energy state carbon dioxide is liquid held under pressure instead of high pressure gas, like it works with compressed air energy storage, this makes it much more efficient

the article is wrong tho. after compression carbon dioxide doesn’t stay at supercritical state, it gets cooled into liquid. text is slop and so are images. there’s more errors

Agents md file doesn’t actually do anything except using more tokens https://arxiv.org/pdf/2602.11988

LEDs themselves are quiet but some SMPSs generate RFI. You can find SMPS that is RF quiet, or since LED strips take so little power, you can make a tiny linear power supply for them, linear power supplies don’t have RF problems

Moxon is very slightly shortened 2el yagi. That other thing is effectively weird phased array of two almost halfwave dipoles, and it’s both worse and bigger, and also harder to make because it requires capacitors for gamma match

(Current rabbit hole: Should a HB9CV’s boom be conductive and electrically bonded to its elements?)

Yes it has to be, that’s how you feed its two elements. Boom is at zero electrical potential and forms half of transmission line that goes to gamma matches of both parts of antenna, and you can attach it to perpendicular conductive mast, or extend it for mounting to mast (has to be perpendicular if mast is metal)

Personally, i’d go with 4el yagi if we’re talking portable operation, because boom length is such that you can make it out of plastic tube and hide elements in it when moving around. Or moxon, if size of 4el yagi is prohibitive. Moxon gets you 2db more gain than HB9CV in similar footprint

openhamprep explanation is wrong

When you consider a segment of wire, it has some inductance and capacitance in that small segment, and the wider it is, the lower inductance and higher capacitance are. In other words, both X_L and X_C go down as diameter increases. Electric field lines within antenna are mostly perpendicular to wire everywhere except on ends, where they spread in all directions, which means that there’s some residual capacitance there that needs to be charged each cycle. This is called end effect and the wider wire is, the more of it you get. In fact, the same aspect ratio (length/diameter) gets you the same end effect ratio each time, and it’s usually in range of 0.98-0.95. If there’s insulation, then insulation has lower velocity of propagation as it has higher permittivity than air, and it is in place with highest electric field intensity, and this can also shorten necessary wire length a couple %. The more insulation there is, the more shortened antenna becomes. have a calculator: https://www.translatorscafe.com/unit-converter/en-US/calculator/dipole-antenna/

But wait, there’s more. We can think of antenna as a lossy RLC resonator (sort of), where R is Rrad which for halfwave dipole would be 72 ohms, + loss resistance which is smaller, and neither are changing fast with frequency. What is changing faster is X_L and X_C, and the wider wire is, the smaller both of them are (X_L = -X_C at resonance), and this means that you can go further off frequency and still have acceptable SWR, i.e. antenna made with wider wire has more bandwidth, or if we look at it as resonator, lower Q. For HF this means using masts or wire cages instead of single wire, but for VHF this gets more practical

Resistive part of antenna impedance near resonance depends on physical antenna length, and if antenna is shortened, then how it was done, but for the range we’re here it won’t change much. But also it will depend on height above ground, type of soil, antenna geometry and many other things. 72 ohm is in freespace only

you can consider antenna wire as a transmission line, but it will need to include ground as the other side of transmission line, and then impedance is dependent on wire diameter to height over ground ratio. it’s not very useful except when considering very large and currently uncommon types of antennas (beverage antenna and rhombic antenna, both of which are traveling wave antennas). other than that, transmission line interpretation only works when antenna is very close to ground in wavelength terms, and usually it’s way below what you need for radiation to work properly. when it’s way up there, or in free space, there’s another impedance that is specific to wire in free space only and not dependent on length, but it’s not very useful for explanation of anything in antennas

careful, they might like it

humans start breathing only when 3 years old, don’t you know?

there are photos of 16 different radios and a couple of antennas, but the one in thumbnail is Elecraft KH-1

It’s up for you to decide. On U/VHF you can talk to other people directly (locally) like on HF. But you can also do things that HF can’t provide, or provides with limitations, like talk through repeater (uncommon on HF), or to ISS, or through satellites (HF bounces from ionosphere) or do longer distance communications from mountaintops, or do image transmission or packet radio (HF has less bandwidth). On receive only you can also download NOAA weather satellite images, or whatever else data are emitted by them. You can make your own repeater from two baofengs. HF gets affected by space weather, U/VHF is not, and we’re entering solar minimum. 6m will take you far further than 2m but it’s usually bundled with HF radios

On higher end there’s also moonbounce, but it’s not in the budget category

e: there’s 50 things you can do with SDR only (many on U/VHF) https://blinry.org/50-things-with-sdr/

Depends on what you want to do. UHF/VHF handheld radio can be had for 20-30, uSDX or QMX type small low power HF radio is closer to 100. You’ll also need battery, antennas (perhaps tuner) and something to put data in and out (headphones and microphone or cw key or audio interface to laptop) (no idea if it’s good but people use it)

related phenomenon. at calm solar surface, there’s only hydrogen and helium. these are excited thermally and can emit radiation, but the highest energy photon they can emit is ca 13eV and 52eV respectively. this is vacuum UV, and this is what is responsible for ionisation of ionosphere even during solar minimum, mostly F layer. but when solar flare forms, there are these giant loops of charged particles, and when charged particles change direction or brake, they release a lot of high energy radiation, that is xrays. xrays just go everywhere and this is partially what is responsible for extra ionisation of ionosphere during solar maximum, and this contributes more to E layer ionisation. (because xrays can go further through air) when solar flare hits the earth, protons from it cause extra ionisation in D layer and this is why post-flare blackouts happen

this is also why one metric of solar activity is solar xray flux

there are also solar xrays, which also ionize ionosphere and are associated with CMEs (regular processes on surface of sun cannot make much xrays, it’s only when high energy particles are smashed back at the surface xrays are emitted. intense magnetic fields are needed for that)

medical chatbot would be malpractice lawsuit pinata

Man brings man to the brink of death, for profit

botnet builders don’t care, and they’re doing this because they started at some point and nobody stopped them

some people say it’s august 8 then august 20

Huh weird. There must be something evil in that pole, it might be a piece of metal or maybe it’s wet or rotting inside. I’d use plastic things to tie it, because natural fibers will remain wet some time after rain, that might degrade performance. (zipties or nylon fishing line or whatever preferably monofilament). I see that bottom is secured too, this is good because in wind antenna could flap around and would stop working if it’s too close to the pole. If twin lead is slightly twisted and under strain (half turn per 30cm or so) then it should flutter less in wind, but you’ve got it spliced and i’m not sure how that would work. This is likely fine as is

J-pole type antennas are effectively monoband. They might work on 3rd harmonic which would be here 70cm band, but most of signal in this case goes up and down that is it’s useless and the signal that goes out horizontally is 6db weaker than what it would be with J-pole for that band. So you can take more precise measurement by zooming in to 130-160MHz or even 140-150MHz, this way you’ll see how low does SWR go at band edges because now you can only see that there is minimum somewhere in the band. I don’t know how much your radio tolerates, but 1:1.5 is generally pretty good. On receive only it might be good also at other frequencies, but dedicated antenna would be likely better

I don’t know if you have calibrated your VNA with cable or not, you can use Smith chart if you do calibrate it with cable but without it, SWR shouldn’t change too hard with any reasonable length of cable (Smith chart rotates once per half wavelength of feedline). This is useful especially if you make your own antennas, but here it’s fine just to make sure that SWR is low