> Here in Germany you have to be careful when setting up a homemade radio signal - it might be illegal depending on frequency and transmit power.
In Germany and everywhere else. The difference is how much it's enforced.
Note that this project isn't using that horrible Raspberry Pi GPIO PWM hack that shits all over RF but an off-the-shelf low power car FM transmitter product. I guess if someone knocks on your door you can point your finger to whoever in Germany sold you that.
At least in the U.S., it's a complete non-issue for an output power that can easily cover the size of a wedding reception as long as you're not using a wide-band transceiver.
You'll want to be "kind" to the extant spectrum and do a responsible frequency sweep to select the "quietest band" prior to broadcasting. And you'll only want to broadcast during the event itself.
The FCC has better things to do than to try and track down an ephemeral milliwatt infringer.
It's the tragedy of the commons. It's a complete non-issue for the offender because it's very unlikely they will face any consequences and less of a non-issue for their neighbor who suddenly can only receive this guy's Spotify on every channel instead of the public broadcast they wanted to listen (maybe exaggerating a bit, depending on the FM transmitter gizmo used, but maybe now it's all buried in noise when it was clear previously). Even the "size of a wedding reception" can cover several homes in a dense apartment block.
But don't underestimate the stubbornness and time some people can dedicate to complaining to authorities. You might have a neighbor that will send letters about how they have to pay mandatory monthly bills for the national public broadcast they now can't listen to. They will complain and complain enough that eventually the broadcaster will send someone over with a spectrum analyzer and then the ball starts rolling. There have been court cases over stuff like that in this corner of Europe.
But I agree, you can argue those offenders went out of their way to cause trouble. In the cases I read people kept doing stupid things even after several warnings and apparently only got their lesson only when dragged into court.
Yes, if you are careless it is possible for you to inconvenience your neighbours, you might even place them in actual danger if you mess with the right frequencies.
Don’t mess with radios if you’re not going to be mindful of your surroundings. But hey, we let people drive cars, those are vastly more dangerous.
I think solid state technology came too soon for the miniaturization of vacuum tube technology to be fully explored. Ken mentions in one of his older posts that even in these old tube-based IBM computers a lot of digital logic was in fact already done with semiconductor diodes, not vacuum tubes. Optimizations like the nuvistors never took off because semiconductors were already more economic.
I guess you could do a whole circuit on photo-etched or stamped sheet metal inside a glass envelope in a similar process that VFDs, although I don't know how you would implement cathode heating. It would be an interesting exercise to think where that could lead you, but I think modern VFDs date much later, when semiconductors already wholly replaced tubes in digital logic.
What fails in a tube is usually the heater filament, which is a wear part with a limited life. Where some (very) expensive tubes did go is to have replaceable heaters - so not more but less integration.
This one provides the source and asks you to build it yourself so at least it has some credibility for the "education use only" claim.
I've seen similar things posted on here before that had a binary build only and zero technical documentation. It was really hard to see any kind of research or education value in those.
Not to detract from the amazing success that is Voyager - I also still remember attending a lecture given by a JPL engineer that worked on one of the instruments - but I feel like the "Voyager has reached interstellar space" thing has been milked to death by PR. There was a period where I feel like there was one such announcement published in media each month with very unsatisfactory explanation (if any) how it differs from the last one.
Because this is getting downvoted, and to check if my memory serves me well:
Here's an excerpt from a 2013 article in Scientific American that appears on the first page of results when searching for "voyager left the solar system" [1]:
> Voyager 1 was starting to get a reputation as the spacecraft that cried wolf, after scientists repeatedly claimed it was leaving the solar system, only to change their minds and say it wasn’t quite there yet.
Somewhat related to spam coming from Google servers, maybe someone can shed some light on what could be the motivation behind this activity:
In recent months I'm seeing instances where random personal mail accounts on a server I run would receive a barrage of mail in a short amount of time.
Mail seems to be bounced via Google Groups - they are sent from Google's IPs and have headers like X-Google-Group-Id, List-*, etc. all pointing to Google Groups. The actual group ID changes after each individual instance of this. However when I actually check e.g. the List-Archive URL, the group appears to be already been deleted.
The content of mail looks like it originates from various (legit-looking) random public web services, support requests, issue trackers, web contact forms etc. For example, a common reoccurring one is Virginia Department of Motor Vehicles (as in something like "thank you for filing a document #123 with us").
No apparent phishing links, no attached malware, no short advertisements snuck into a text field etc. Just automated replies from "noreply@"-type addresses.
It does not seem to be the case of trying to hide another attack (as discussed here for example: https://news.ycombinator.com/item?id=47609882) - over many instances I've not seen any other malicious activity. And this mail is filtered out easily enough based on Google's headers.
It all looks like there is some bot that a) creates a Google group and subscribes (one or more) random email addresses to a Google group and then b) enters the group's mail address into a bunch of random web forms that then send their automated responses to the group.
What could be the motivation for this? After the fact it's filtered pretty easily based on headers. It's not nearly enough volume to DoS the server. But why would someone go through the trouble of setting this up?
This is almost certainly subscription bombing / email bombing. The goal is to flood someone's inbox with hundreds of legitimate-looking automated emails so they miss a real one - typically a password reset confirmation, a purchase receipt, or a "new device login" alert. The actual attack is happening on some other service where the victim has an account. The fact that you don't see it on your server doesn't mean much, the target is the victim's primary inbox elsewhere.
My thinking so far against was 1) after a few months I'm pretty sure I would hear about the real attack 2) Repeating too frequently. People aren't getting hacked all the time (I hope).
But who knows? Now I'm thinking that maybe some other step in the attack is failing and maybe the attackers just trigger the email bomb part pre-emptively in case they actually succeed in resetting the password/purchasing/whatever.
Yes. I got the same issue… and when someone replies, all users in the mailing list receive it… that’s why I would see a ton of replies saying please remove me from your mailing list. Very annoying. The only solution I found was to create an inbox rule to reject those, as I couldn’t unsubscribe
I just block the group address on the MTA, but it doesn't matter. In all instances so far when it came to my attention the group was already deleted. Next time they will use a different group and I don't want to blanket ban all Google Group mail for my users.
It's not even that much of a hassle. What worries me is that I don't understand why someone would go through the trouble of doing this for no apparent benefit. I hope I'm not somehow unknowingly enabling some sort of an attack on any of the entities sending these automated replies.
This complaint was sent to Google, probably because the cloudinary.com URL appeared in their search results.
It's doubtful anyone at Fiverr was made aware of this - unless Google typically forwards these complaints to the actual host of the offending URL. Even then, it would go to Cloudinary who would in turn need to notify their client. Many hops with plenty of "someone else's problem" barriers for the message to overcome.
Wiring mistakes can kill or burn down a house months or years after they have been done. You will not notice unconnected protective earth or badly dimensioned circuit breakers until something else breaks and the protective element is not there.
In Germany and everywhere else. The difference is how much it's enforced.
Note that this project isn't using that horrible Raspberry Pi GPIO PWM hack that shits all over RF but an off-the-shelf low power car FM transmitter product. I guess if someone knocks on your door you can point your finger to whoever in Germany sold you that.
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