Not directly electronics but many in the electronics world use 900MHz devices for all sorts of applications. As a license free band, it's attractive for experimental remote control, remote monitoring (my remote Cosmic Ray monitoring project uses a one way 900MHz data link, our church uses 900MHz wireless microphones, my wife has a a pair of 900MHz headphones that blow the socks off any Bluetooth device)

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There is an ISM allocation used for industrial, scientific and manufacturing. If NextNav succeeds in convincing the FCC to either sell or simply assign large parts of the 900MHz band, a lot of users are going to lose.

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https://www.eff.org/deeplinks/2024/09/nextnavs-callous-band-grab-privatize-900-mhz

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I'd say write the FCC to complain but the FCC appears to have become the federal governments frequency sales store.

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Look at the UHF repack as an example.

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I posted this more out of frustration then expecting anything any of us do to have any effect on the FCC. I expect them to go after the 2M and 70cm ham allocations any day now.

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I made a mistake, in my description of a ultra simple current limited LED driver.

Call the cyber police to take my PCs from me.

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[Me making a mistake ought to make at least one person in this group smile. I live to please.]

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I transposed the position of two components.

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The capacitor goes between the AC Hot and full wave bridge, not the other way around.

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The AC from the mains passes through the capacitor, the current is determined by the capacitor value (Xc) and mains frequency.

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Higher capacitance equals higher current.

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The now current limited AC passes through the full wave bridge producing 120Hz pulses of DC (100Hz pulses of DC in 50Hz nations]

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This safely (if the capacitor value isn't too large) provides current to power/drive a LED or LEDs. My fake florescent LED replacement tubes have a lot of small SMD LEDs. I quit counting at 50ish. I'd guess there are about 200.

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Note that is a guess and I won't pretend it is "mainly accurate," don't know, don't care.

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I laid it all out on my work bench, out of the protective plastic tube, and used a capacitor substitution box to pick the 'right' value capacitor.

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I kept feeling the LEDs and when they were just perceptible warm I backed down one step.

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Is the brightness optimal? Snort hardly.

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Is it efficient? Give me a break, nope, hardly.

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But 4 of them provide about 10% more light as 2 real florescent lamp tubes.

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Oh that 10% figure comes from a 50 or 60 year old professional light meter that, in 2008, agreed with a new, NIST traceable calibration, light meter, so I suspect it hasn't degraded in the 16 years....might well be wrong ...sort of "I hope it's mainly accurate."

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Best I could do on a moment's notice. I need to take it in to the lab for calibration....but then what does the odd spectra do to calibration....

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And yea I had to rewire the fixture. Oh how sad. I dispensed with sockets because it was cheaper and easier, I'd have had to go to a real electrical supply house for sockets and they might not sell to a civilian they don't know, my EE diploma would get laughs, and EE can't change a light switch for hire in Kentucky. So I hardwired everything and used home made Lexan spacers. Looks more then OK, actually looks store bought if you don't look too close....but who cranes their neck to inspect a florescent light fixture?

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The LEDs face down so the reflector is sort of useless.

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So yea WN4ISX made a mistake.

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Yawn.

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I'll tell on my self.... during a graduation when we used rented professional 2M business band radios and I ID with my ham call instead of my name. That was a really big no no, but I was used to using my ham call on an HT and habbit won over the law. And there were negative consequences.

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The company monitored all comss with their radios and reported me to the FCC. The company owner was beyond upset. I have no idea why, it wasn't like anyone was going to waste time listening to 3 TV crews rush from staging area to staging areas and trying to set up with zero time.

I was part of it and it was BORING!

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?But the Freaky Candy Company has zero sense of humor.

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I still have the pink ticket framed on my wall in a place of pride, Paraphrased is says "Thou shalt not make this mistake again upon risk of forfiture of license."

They get real twitchy over IDing the wrong license in the wrong radio service.

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[Again, damn sure wish I could spell.]

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Sorry I'm far from perfect but mainly accurate. At least I got the link to the graphic of the diagram right...

Again

From Kia

https://www.kia.com/us/en/privacy

Sensitive Personal Information.

This category may include Social Security number, driver’s license, state identification card, or passport number; account log-in, financial account, debit card, or credit card number in combination with any required security or access code, password, or credentials allowing access to an account; precise geolocation; racial or ethnic origin, religious or philosophical beliefs; union membership; genetic data; unique biometric information; citizenship or immigration status; contents of certain mail, emails, and text messages; or health, sex life or sexual orientation information.

?[Collected?] Yes

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--------------------------------------------------------------------------------

Please note the genetic data.

The privacy notice says the car can collect this data.

----------------------------------------------------------------------------------

https://owners.kia.com/us/en/privacy-policy.html?_cl=zUZJXivZklINSZMXXvgtS69w

-------------------------------

I'm only including " racial or ethnic origin;" which again requires a fairly complete/complex DNA analysis to determine.

----------------------------------------------------------------------------------

As to main accurate, I'm happy if I'm 95% accurate because accuracy depends on complete knowledge of a subject and knowledge is expanding at a geometric rate, I doubt if anyone can stay 99% accurate given the rapid expansion of knowledge.

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Consider the new magnetic phenomena...I had no idea it existed until it was mentioned here. I try to keep up with topics that interest me the most. I'm a lot more up to date on Clovis Amerind Culture and The Younger Dryas event then I am nuclear weapons.

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I am extremely familiar with the electrical system in our 2001 Volvo S60 and am woefully and willfully ignorant on the electrical system of a gasoline powered 2025 Volvo anything.

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Toyota apparently added CAN to the 2003 Echo, so my knowledge of 2001 Echoes would be mainly inaccurate, however that knowledge is "mainly accurate" for 2000 and 2002 Echos.

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So mainly accurate is probably good enough for my life and goals.

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Another real world example, let's say I need an emergency antenna for 3.58MHz, [300/3.58] divided by 2 would give me the approximate length of each leg of a dipole antenna in meters, and, while not perfect because of end effect and the effect of height over the earth and the conductivity of the earth below said dipole, the antenna would work reasonable well, probably as good as 95% as good as though I did everything absolutely right, measure the VSWR, adjust the leg length or change the height of the dipole to achieve a perfect 1:1 VSWR.

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Of course that 1:1 VSWR would be at the end of a feedline and, unless I used a matching transformer to transform the 72~75 ohms of the antenna to 50 ohm coax, or a balan (balanced to unbalanced) transformer to couple to 75 ohm coax, I couldn't be certain the 1:1 was really 1:1. One can spend a lot of time tweaking minor variables that will have no discernable influence on behavior or function.

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So, even if I do everything to the best of modern technology, it will only be 'mainly accurate.'

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I'd stick a piece about engineering back in the days of the slide rule when everything was mainly accurate.

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My Echo specs a tire pressure of 32 PSI. Will 32.1 or 31 or 33 make any difference in drivability? Gas mileage? Tire wear? Doubt it, don't care, is my gauge 100% accurate, can I trust it when it says 32PSI? We have 4 "identical" [of the same manufacturer bought at the same time...but are they the same inside?], they all give the same reading. Is it accurate? Is there a design flaw? How can I verify this one way or the other? My compressor also has gauges, they almost agree with our tire pressure gauges, they are about a half PSA [eye balling here] so which do I trust? Either? Both? Neither?

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I consider ~1/2PSA to be "mainly accurate" with our instrumentation and have way too many other things to worry about then "Which gauge is the most accurate?"

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Although I do wonder about the temperature effect on the little brass (probably brass, every gauge I've opened has brass) bulb that is filled, distended and the distortion produces the PSI indication.

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Is it the same at 0F and 100F?

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I've had to check tires at each extreme.

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I won't go into "Which of my voltmeters is really 100% accurate." I know which one I trust the most, it gets checked at the EE instrumentation and measurement lab every 6 months or so, has been accurate since March 1974, I expect any gross failure will be obvious...could be wrong.

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Or consider an oscilloscope, assuming the inards are 100% accurate, how accurate can I read a line of illuminated phosphor or simulation on a LCD screen.

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The line has a physical width, can I be certain it's 1V or might it be 1.001V or 99.09V. Assuming 1V is mainly accurate is probably the most logical thing to do.

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Although only a fool or new tech would try to achieve more then 0.1V mainly accurate on most scopes because they are not designed to give 5 digit accuracy.

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I suspect if you are honest, you'll admit most decisions in your life are based on the "mainly accurate" concept.

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BTW, I didn't come up with 'mainly accurate' it came from a presentation by some NASA/USAF engineers to my engineering class.

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One older guy said something like "Striving for perfection is a waste of time because you will never know all the variables to even 6 places, go for the best data you can obtain, do your math right and it will work out."

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Which can be translate to "mainly right."

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The orthopedist who replaced my knees had many responsibilities....some shared with other people like the anathesthologist. [God I wish I could SPELL!]

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But neither had ran into someone with congenital?methemoglobinemia [look it up, I am not wasting 20 pages with the boring details, let's just say my blood is a bit messed up]. They were uncertain how to sedate me for surgery. The normal method is? spinal block but the drug used might trigger a massive MH event...so they played it safe and knocked me out with a "probably safe medication." I had to sign a waiver acknowledging the limited knowledge on MH triggers.?

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Did they fail in their responsibility? My knees had to be replaced or I'd be in a wheel chair now.

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They went with the best data they could find, mainly accurate might well apply.

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And no one in the hospital knew a single color pulse oximeter is useless with MH attacks. I know quite a bit about MH, probably more then any single doctor or nurse because I have MH. I have over a terabyte of data on MH. There was honest to God near panic when I handed them the paperwork detailing weaknesses of single color pulse oximeters. They don't work too well on carbon monoxide poisoning either. I probably had the only dual color pulse oximeters in the city, quite likely the state. All because a former EE classmate works for a company that makes medical gear, I told him over lunch and he had his team design a dual color pulse oximeter and gave me one. They used theirs and mine, wanted to keep mine because I have cousins with MH and they might show up at the hospital. It might be selfish but I kept mine.?

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They bought 10.

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I've been pulled from swimming pools 3 or 4 times because the lifeguard thought I was having a heart attack because I'd gone cyonotic all over. Big Bad Bummer. Cold, intense emotion, fear, many solvents, can trigger MH events. Look up Blue Fugate. forget their geneology, they've got it all wrong. A nephew did not marry his aunt, he married his first cousin on his mothers side. BTW, many states allow first cousin marriages, only NC forbides double first cousin marriages.Bet you didn't know that. That's part of my mainly accurate knowledge of marriage laws in the USA. BTW, I married a nice woman from Northern Kentucky, totally unrelated, who puts up with me and my odd interests. I mean what normal EE cares about "Why did Clovis Culture end?"

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I could go on but I've beat this dead horse into nice jerky quite well...

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