Homemade device creates RF interference in Ohio, USA - Page 1
Forum section: electronics / general

author: sokoloff
author_rank: Super Contributor
timestamp: May 05, 2019, 01:32:20 pm
content: https://fox8.com/2019/05/04/source-of-key-fob-garage-opener-interference-solved-in-north-olmsted/Alright, which one of you guys was it?Quote

author: strangersound
author_rank: Regular Contributor
timestamp: May 05, 2019, 05:06:30 pm
content: That's funny. I wonder what error he made? I would assume his device was supposed to be like any other smart device and communicating with his network; but as much RF as he was generating, I'd wonder what the hell he had going on. The news video is funny. The officials were definitely amused. Said they killed power to the whole neighborhood trying to figure out where it was coming from, but it was on a battery setup. They said the signal was so strong you couldn't localize it. They had to go door to door as a last resort.That's pretty funny when your home made smart device jams a a whole frequency range in a few block radius. I can only guess this was going on for weeks on end until some quirky circumstances made a couple of affected people realize they had the same weird problem.

author: sokoloff
author_rank: Super Contributor
timestamp: May 05, 2019, 05:11:22 pm
content: I'm curious as well.I'm currently guessing that he bought an off the shelf 315MHz module and sent a continuous stream of data out of it inside an Arduino loop() function, blowing out the duty cycle limits on the band.

author: TheSteve
author_rank: Unknown
timestamp: May 05, 2019, 07:55:39 pm
content: Clearly the people looking for it didn't have the right equipment. With the proper stuff(and some experience) you can narrow it down to the part of the room it is in quite easily.

author: Lord of nothing
author_rank: Super Contributor
timestamp: May 05, 2019, 10:25:44 pm
content: Quote

author: coppercone2
author_rank: Super Contributor
timestamp: May 06, 2019, 04:51:38 am
content: a good reason why a hobbyist should have broad band antennas at his disposal (often cited as being useless), to detect problems.

author: Brumby
author_rank: Unknown
timestamp: May 06, 2019, 05:43:32 am
content: Quote from: TheSteve on May 05, 2019, 07:55:39 pmPerhaps - but the interviewee talked about conducted as well as radiated fields, which turned a lot of household wiring into antennae - plus - from the sounds of it, there was a lot of power in the transmitted signal. Maybe they needed a detector with a different sensitivity range - such as a piece of wet string tied to one leg of a neon bulb.

author: TheSteve
author_rank: Unknown
timestamp: May 06, 2019, 06:52:47 am
content: A directional antenna alone would not work. That will get you close but then the front end of the receiver would be swamped and even with high levels of attenuation the signal will leak into the receiver, coax etc and no longer provide a directional signal. You need to get a little more advanced and use what is often called an "offset attenuator". You vary the level of a mixed signal which then gives nearly infinite attenuation so even if the signal source is several watts and you are less then a meter away the directional properties of the antenna still work.Amateur radio fox hunts(hidden transmitters) use this setup quite often, it works extremely well.

author: Brumby
author_rank: Unknown
timestamp: May 06, 2019, 07:14:59 am
content: Ah. You learn something every day.Still, the conducted RF on wiring would make life interesting, I would think.

author: Dataforensics
author_rank: Unknown
timestamp: May 06, 2019, 07:20:56 am
content: Could not access in UK either until I changed VPN country to US. Perhaps still due to gdpr.

author: soldar
author_rank: Super Contributor
timestamp: May 06, 2019, 04:39:08 pm
content: Quote from: Lord of nothing on May 05, 2019, 10:25:44 pmI get the same message and I am getting it more and more. It is a result of the stupidity of EU legislation. American content providers find it easier to just not deliver their content to Europe.The solution, obviously, is to VPN to America.

author: TassiloH
author_rank: Regular Contributor
timestamp: May 06, 2019, 05:08:54 pm
content: For a quick peek at US news sites which block EU/Germany I usehttps://hide.me/en/proxy(select USA as proxy location)

author: soldar
author_rank: Super Contributor
timestamp: May 06, 2019, 05:16:55 pm
content: Quote from: TassiloH on May 06, 2019, 05:08:54 pmthanks! I bookmarked it.

author: Lord of nothing
author_rank: Super Contributor
timestamp: May 06, 2019, 06:17:30 pm
content: QuoteNope the dont show it so I dont need to see it.

author: soldar
author_rank: Super Contributor
timestamp: May 06, 2019, 06:41:52 pm
content: QuoteSome unspecified interference was being caused by some unspecified device owned by some unspecified person for some unspecified purpose. But don't worry, everything is OK now.Very poor reporting.

author: magic
author_rank: Super Contributor
timestamp: May 06, 2019, 08:18:05 pm
content: Quote from: soldar on May 06, 2019, 04:39:08 pmI don't understand what makes them feel compelled to comply with this bullshit rather than ignore it altogether. It's not like they care about compliance for the sake of staying in this market since they clearly don't give a damn.Maybe they just want to punish us

author: soldar
author_rank: Super Contributor
timestamp: May 06, 2019, 11:15:19 pm
content: Quote from: magic on May 06, 2019, 08:18:05 pmI don't know but it could be that large publishers may have a presence in Europe where the EU authorities could get at them.

author: soldar
author_rank: Super Contributor
timestamp: May 09, 2019, 06:01:35 pm
content: https://www.thestar.com/news/world/us/2019/05/05/a-mystery-frequency-disrupted-car-fobs-in-an-ohio-city-and-now-residents-know-why.htmlQuote

author: Richard Crowley
author_rank: Super Contributor
timestamp: May 09, 2019, 06:31:51 pm
content: Back in high school, I found a large (0.5 m3) navy gray high voltage transformer with 3 inch tall secondary ceramic output terminals. I got some 1/4 inch copper tubing and bolted a couple of 1m lengths onto the output standoff terminals. I bent them into a V shape and made a gigantic Jacob's Ladder. It was spectacular. By the time the arc reached the top of the V, it was a giant flame (reminiscent of the Eye of Sauron). We found out the next day that it knocked out radio and TV reception for several blocks in the neighborhood.