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I read this story recently where a guy drove and jammed people's smartphones on a daily commute. So I was thinking he probably made his own jammer, but it turns out these jammers are readily available for purchase.

A simple google search netted bunch of sources. The first one being in the US ( just happily selling you RF jammers. They are even advertised on TV.

You technically can't even sell gear without FCC certification for EMC / EMI testing, yet these guys sell gear made precisely to do what it's not allowed.

What am I missing?

You've made the assumption that US laws actually apply globally. isn't based in the US (google tells me they're headquartered in Sweden), and they ship from japan, china, taiwan, or korea (that's stated on their site). For the most part, these laws you speak of don't actually apply to them. When you order from them, YOU become the importer and the breaker of applicable laws.
Look into if the transformer is a bit under-rated. If the transformer is going into saturation you may be getting that sound. Peak currents may be more than you expect.

Check the capacitors against the datasheet or reference design. Not sure how the circuit will behave if input or output capacitance is low at the operating frequency. Actually, because it's switching you will need it at a good 5x the switching frequency.

What is the nominal switching frequency compared to the reference design? Is it that spike around 500 kHz?

Are tracks between the switcher and the transformer nice and short, or is there some inadvertent large loop?
General Chat / Re: What did you buy today? Post your latest purchase!
« Last post by bitseeker on Today at 05:12:26 AM »
I still can't believe that Drok "sale." What a score.
Repair / Re: Tek TDS744A slow refresh or recovery
« Last post by Daxxin on Today at 05:12:25 AM »
::) i'm too late reading yours replies..  i have 2 M5M51008 but 100ns instead 70ns replaced alredy , well before the test very short (run 30 seconds without any graphical shapes tests) then i was getting
processor fail , now seems the test is running very long then at the end i'm getting the banner instead the result and the scope freeze stucking on the banner , do you think slower sram can cause this?
by the way ordered alredy the correct sram.

Is switch 3 on the dip switch set on or off?

this the actual dip switch positions

Test Equipment / Re: Test Equipment Anonymous (TEA) group therapy thread
« Last post by tautech on Today at 05:09:29 AM »
Don't think I'd like to go either when guns are so easy to get hold of, why the hell would you want to have gun about you anyway in a so called civilised country, beats the hell out of me.
Critters and RATTLESNAKES !  :scared:
Metrology / Re: Heated housing for voltage references
« Last post by Conrad Hoffman on Today at 05:09:10 AM »
Steel is a dreadful heat conductor. I'd use an aluminum box to even out the heat and give less delay. It makes sense to put the sensor at the point of interest, but you can often do better by closely coupling near the heater because of the reduced delay, as long as the box is highly conductive.
Beginners / Re: Getting started in Embedded Linux
« Last post by yashrk on Today at 05:08:39 AM »
Look into Toradex, they offer a wide variety of SOMs and carrier boards (which they market as custom SBCs). I have found their documentation to be pretty good so I'd recommend looking through their developer pages.

Octavo Systems makes a really cool product, I've never used it so I can't say how easy it would be to use it in a product. The Beaglebone Black and Beaglebone Pocket use it, so buying one of those boards could be a good starting point.

Thank you, buddy, you might just have solved my biggest problem  :-+ Emailing vendors now
Test Equipment / Re: Test Equipment Anonymous (TEA) group therapy thread
« Last post by BravoV on Today at 05:07:41 AM »
Guys, stick on the "Test Equipment" only, please.
For technical reference here is a triband jammer. Basically 3 tuned VCOs turned on and off. Lithium battery on the other side + 3 helix antennas

General Chat / Re: What did you buy today? Post your latest purchase!
« Last post by ChrisLX200 on Today at 05:07:26 AM »
Part 1 of the Great Amazon Drok £3.99-for-anything sale :)  5 x DPS5015, 15A motor controller, and a Tesla lighter. Also bought one case for a DPS5015 and a mini 3-jaw chuck (the latter 'cos the minimum size for my miller's main 16mm Albrecht chuck is 3mm and I got fed up with having to swap the chuck out for a smaller one when I want to drill/tap 3mm threaded holes).

Part 2 should arrive tomorrow..
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