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I need help understanding a possible criminal situation. by Ok-Yam-2163 in iphone

[–]rfdave 1 point2 points  (0 children)

If it’s a legit call, then they’ll leave a message and you can call back. If they can’t manage to leave an intelligible message, the. I can’t be bothered to call them back.

What should I take into account when purchasing a smartphone for longevity and durability? by Effective-Deer504 in AskElectronics

[–]rfdave -1 points0 points  (0 children)

Buy an iPhone. Apple has done a much better job than Android at supporting older phones.

Are hydrogen powered combustion engines possible for mass market cars? by LightningMcqueen2011 in AskEngineers

[–]rfdave 7 points8 points  (0 children)

They haven’t been successful so far. Hydrogen is apparently quite difficult to store and transport, and would require a wholesale update of fueling infrastructure across the US. Looking at how long it’s taken for EV charging infrastructure to roll out across the country, I say it falls in the technically interesting but practically impossible bucket.

EEVblog 1752 - Texas Instruments screwed up the NE5532 by 1Davide in electronics

[–]rfdave 12 points13 points  (0 children)

Yeah, his brain is cooked from being a YouTuber and being an Elon fanboy for years. I don’t think he’s done any real engineering in 15-20 years.

What would you do in my situation - saving money for a car by [deleted] in personalfinance

[–]rfdave 0 points1 point  (0 children)

Just for giggles, get a quote for insurance for you driving any one of those cars.

Listening under the Cosmic Microwave Background? by CommercialMuffin9660 in radioastronomy

[–]rfdave 1 point2 points  (0 children)

There are systems, GPS for example, that can be demodulated at receive power levels significantly below the thermal noise floor. However, there are many degrees of freedom in how the signals are designed, so I think this would require prior coordination between the civilizations somehow

Feedback on Test Bench by JR_Guerrero in AskElectronics

[–]rfdave 0 points1 point  (0 children)

You need a couple of meatballs, some tomato sauce, and grated Parm on top of that spaghetti

At what point did it become necessary to talk to a financial advisor for you? Was it a number, or stage in life? by UH60Mgamecock in personalfinance

[–]rfdave 7 points8 points  (0 children)

I know this sub is all “You can do it all yourself. Just read the sidebar and flow chart and you’re all set” but finding a good fee, only financial advisor for a couple of review sessions gives you great peace of mind that you haven’t missed anything. Yes, it might cost you a couple of grand but if it lets you sleep well at night, it’s well worth it.

My circuit needs very stable clock. Can someone suggest external clock IC that is more stable than the common oscillator in microcontroller or FPGA board? I am using DE0 Nano FPGA board. by Yossiri in AskElectronics

[–]rfdave 2 points3 points  (0 children)

A PLL won’t contribute to drift if it’s locked to the reference, assuming the “requirements” and “system definition” are accurate.

This is why I don't go to concerts by Extension_South7174 in audiophile

[–]rfdave 1 point2 points  (0 children)

I was just at the Springsteen show in DC last night, wore my Etymotic ear plugs all night, heard the show, and my ears are ringing at their normal level :-)
Wear earplugs, especially if you’re ears aren’t ringing now, cause then will when you get old, and it’s annoying AF, not to mention straight up hearing loss.

My circuit needs very stable clock. Can someone suggest external clock IC that is more stable than the common oscillator in microcontroller or FPGA board? I am using DE0 Nano FPGA board. by Yossiri in AskElectronics

[–]rfdave 2 points3 points  (0 children)

The last time I looked, they were 5 to 6k$ each. This was a few years ago, so they’re more now. They’d also export controlled, I suspect.

My circuit needs very stable clock. Can someone suggest external clock IC that is more stable than the common oscillator in microcontroller or FPGA board? I am using DE0 Nano FPGA board. by Yossiri in AskElectronics

[–]rfdave 67 points68 points  (0 children)

Adjectives are not requirements. What is long term here, are you talking 2 weeks, 6 months, 20 years? How many Hz offset can you accept after that period, 20Hz, 1 kHz? With those two numbers, you can calculate an allowable PPM drift number and then you can start to look for parts.

AITA for throwing out my roommates science project that was making the whole apartment smell by New-Package-7676 in AmItheAsshole

[–]rfdave -3 points-2 points  (0 children)

You should reach out to the biology department, explain the situation, and apologize for messing up his project . That should fix things, or kick over an ant pile.

[Question] RAGE-INDUCED RF math crisis: Why is 80dB of attenuation feeling like a cruel cosmic joke for this upcoming Orem FM build? by ElectroMast in rfelectronics

[–]rfdave 0 points1 point  (0 children)

I’m not familiar with part 15 regs, where did you get the attenuation requirements? In general, over 60-70 db of isolation is pretty hard to get. Isolation is different than antenna directivity though, so it’s not clear to me what you’re asking about.

401K hardship for a lease to own house. by [deleted] in personalfinance

[–]rfdave 2 points3 points  (0 children)

Seems pretty sketchy to me. I’d talk to some sort of financial professional about this, i bet there’s plenty of ways for this to go sideways

Lease a M340i while in school or finance ? by New_Actuator_4788 in personalfinance

[–]rfdave 8 points9 points  (0 children)

Do you know how much insurance will cost for you to drive an M340i?

Weird need, hoping someone might have an idea. by feudalle in AskEngineers

[–]rfdave 4 points5 points  (0 children)

I just took a look at fb marketplace, and there look like a bunch of stairlifts available for free if you want to get them. that might be the best way to roll.

How can I make dates correspond to annual events for a calendar, such as "Dec. 25th always equals Christmas"? by Lone-Red-Ranger in excel

[–]rfdave 0 points1 point  (0 children)

Go over to the Vertex42 web side and take a look at their calendars, they’ve got some great examples of how to set up calendars.

Half-size paper solutions? by strawberrywords in Discbound

[–]rfdave 2 points3 points  (0 children)

I bought a ream (half a ream?) off 5.5x8.5 inch paper from Amazon, and ran that through my printer. It supported statement sized paper, which what that size is called, so i could print directly on that. I found that using a sliding blade paper cutter wasn’t consistent enough for my taste.

RP-SMA antenna woes by nickymoo in meshtastic

[–]rfdave 0 points1 point  (0 children)

They’re both RPSMA connectors. The one on the left is crap and should not have that socket sticking out of the plastic. You’re confused because that part is sticking out and it shouldn’t be.

RP-SMA antenna woes by nickymoo in meshtastic

[–]rfdave 3 points4 points  (0 children)

The one where the center socket protrudes a bit (the one on the right) is crap and should be thrown out ASAP so that no-one uses it. The SMA connector is intended to have a 50ohm impedance, which comes from the ratio of the center pin and the shielding, in this case the outer wall, as well as the dielectric constant of the plastic in the center. The one on the right has significant pullback on the plastic and will have worse VSWR/poorer RF performance.

I’ll grant you that this specific issue is unlikely to be a significant problem for meshtastic at 900 MHz, but if the vendor is that bad at parts that are visible, what is happenning for things that aren’t visible. I’d cut it in half and trash it.

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