3 ms·

There are tons of cheap electronics (including but not limited to switching power supplies) that are not properly EMI shielded or even not shielded at all. It w

by devy 10y ago

There are tons of cheap electronics (including but not limited to switching power supplies) that are not properly EMI shielded or even not shielded at all. It would be great to have a portable device that can detect and locate the EMI/RFIs. (Perhaps there are already some on kickstarter?)

cozzyd 10y ago
Raspberry pi + RTL-SDR + screen + battery?
- devy 10y ago
  Not for the faint of heart :) Is there a off the shelf product ?
  - dbcurtis 10y ago
    Spectrum analyzer and appropriate antenna.
  - deleted 10y ago
    [deleted]
  - cdawzrd 10y ago
    RF Explorer is a "budget" option at around $300-400: http://rfexplorer.com/models/ http://rfexplorer.com/models/ Professional handheld spectrum analyzers are in the $3k-50k range from the likes of Keysight, Anritsu, etc.
    - tegansnyder 10y ago
      Many vendors will also rent out them by the day. There used to be a company in Denver that did back in my WISP days.
  - Florin_Andrei 10y ago
    Plug a cheap SDR dongle into your laptop and install some free software SDR app. http://www.rtl-sdr.com/ http://www.rtl-sdr.com/ It might seem like the poor man's approach, but plug a good Yagi antenna into that dongle and it becomes quite powerful.
    - platz 10y ago
      with an android phone and a usb-otg cable, you can plug the rtl-sdr directly into your phone and use an app to view/listen to the spectrum
      - morganvachon 10y ago
        The rtl-sdr dongle I have (ATS-B receiver) draws too much current to be used with my tablet (Nexus 7 2013). At minimum, a powered USB hub would be required in this setup for it to work properly.
        platz 10y ago
        I have a RTL2832U/R820T reciever ( https://www.amazon.com/NooElec-NESDR-Mini-Compatible-Packages/dp/B009U7WZCA/ https://www.amazon.com/NooElec-NESDR-Mini-Compatible-Package...) (note - there are newer models now) and it works fine with a samsung galaxy note 3. http://sdrtouch.com/ http://sdrtouch.com/
    - superkuh 10y ago
      rtl_power frequency hops at about 80 MHz/s max. You can use https://github.com/xmikos/qspectrumanalyzer https://github.com/xmikos/qspectrumanalyzer or many other rtl_power frontends to see it in real time as you point the antenna. For windows there's https://github.com/pavels/spektrum https://github.com/pavels/spektrum Another approach seen on hackernews in the past had an omnidirectional antenna and used GPS tagging to make heatplots at different frequencies overlayed on a map. ref: http://www.tautology2.net/heatmap/ http://www.tautology2.net/heatmap/ It uses the http://eartoearoak.com/software/rtlsdr-scanner http://eartoearoak.com/software/rtlsdr-scanner software.
- viraptor 10y ago
  https://learn.adafruit.com/freq-show-raspberry-pi-rtl-sdr-scanner/overview https://learn.adafruit.com/freq-show-raspberry-pi-rtl-sdr-sc...
leetbulb 10y ago
The article states that they used "a Radar Engineers 240A Noise Signature Receiver and UHF Yagi antenna to survey the affected block." Looks like a somewhat portable device (MODEL 243): http://www.radarengineers.com/rfitvi.htm http://www.radarengineers.com/rfitvi.htm Although it's probably going to cost you $5-10k USD. Pretty easy to hook up a RTL-SDR ($10) to a cheap Android tablet loaded with SDR Touch for simple surveying.
- tzs 10y ago
  I tried to get a price check by dropping "Radar Engineers 240A Noise Signature Receiver" into Google's shopping search, and for some reason all it gave me was one result: a "My Little Pony Friendship is Magic Guardians of Harmony Fan Series Figure - Princess Celestia" from Toys'R'Us. Google is very weird sometimes. Note: I have never watched "My Little Pony", collected anything related, visited any My Little Pony fan sites, read any My Little Pony fan fiction (not even accidentally, via crossovers from fandoms whose fiction I do read), or done anything else to show any interest whatsoever in My Little Pony. Google has a ton of information about me with regards to things I might actually buy, so why the heck did they pick My Little Pony? (Heck, I'm pretty sure they have figure out that I have a ham license...surely they have something more relevant for me than My Little Pony).
  - dekhn 10y ago
    I get the same results so I let Google know the results weren't correct. If you drop any one word from the query, you get better results.
  - i_are_smart 10y ago
    Just one result? I wonder if it was one of their plant results. I've heard rumors of Google seeding some (just a few) obscured google searches with totally irrelevant results, so they can catch competitors scraping results from their site.
  - KMag 10y ago
    Back when I worked at Google on the indexing system, the guy who sat next to me introduced http://www.nextthing.org/archives/2006/10/26/rolling-garfield-ninja-turtles http://www.nextthing.org/archives/2006/10/26/rolling-garfiel... . In his defense, it was someone else's code that he started using more broadly, and there was a latent bug in the third person's code that didn't special-case a sentinel value used for one of the similarity metrics. So, he added some analysis, and all of a sudden Google thought all of the pages that didn't have this similarity metric calculated were all extremely similar. Our manager bought him a stuffed Garfield as a "prize" for breaking Google.
fixermark 10y ago
I grew up in a home with an early-model SyQuest cartridge drive hooked to a Macintosh via SCSI. When the rabbit-ears TV in the same room was turned on and tuned to the right frequency, you could hear the leakage from the drive; it sounded like lower-frequency modem chatter. Not entirely sure what part of the drive was leaking that much RF, but I don't think it was intended to work that way.

by devy 10y ago

cozzyd 10y ago

Raspberry pi + RTL-SDR + screen + battery?

devy 10y ago
Not for the faint of heart :) Is there a off the shelf product ?
- dbcurtis 10y ago
  Spectrum analyzer and appropriate antenna.
- deleted 10y ago
  [deleted]
- cdawzrd 10y ago
  RF Explorer is a "budget" option at around $300-400: http://rfexplorer.com/models/ http://rfexplorer.com/models/ Professional handheld spectrum analyzers are in the $3k-50k range from the likes of Keysight, Anritsu, etc.
  - tegansnyder 10y ago
    Many vendors will also rent out them by the day. There used to be a company in Denver that did back in my WISP days.
- Florin_Andrei 10y ago
  Plug a cheap SDR dongle into your laptop and install some free software SDR app. http://www.rtl-sdr.com/ http://www.rtl-sdr.com/ It might seem like the poor man's approach, but plug a good Yagi antenna into that dongle and it becomes quite powerful.
  - platz 10y ago
    with an android phone and a usb-otg cable, you can plug the rtl-sdr directly into your phone and use an app to view/listen to the spectrum
    - morganvachon 10y ago
      The rtl-sdr dongle I have (ATS-B receiver) draws too much current to be used with my tablet (Nexus 7 2013). At minimum, a powered USB hub would be required in this setup for it to work properly.
      - platz 10y ago
        I have a RTL2832U/R820T reciever ( https://www.amazon.com/NooElec-NESDR-Mini-Compatible-Packages/dp/B009U7WZCA/ https://www.amazon.com/NooElec-NESDR-Mini-Compatible-Package...) (note - there are newer models now) and it works fine with a samsung galaxy note 3. http://sdrtouch.com/ http://sdrtouch.com/
  - superkuh 10y ago
    rtl_power frequency hops at about 80 MHz/s max. You can use https://github.com/xmikos/qspectrumanalyzer https://github.com/xmikos/qspectrumanalyzer or many other rtl_power frontends to see it in real time as you point the antenna. For windows there's https://github.com/pavels/spektrum https://github.com/pavels/spektrum Another approach seen on hackernews in the past had an omnidirectional antenna and used GPS tagging to make heatplots at different frequencies overlayed on a map. ref: http://www.tautology2.net/heatmap/ http://www.tautology2.net/heatmap/ It uses the http://eartoearoak.com/software/rtlsdr-scanner http://eartoearoak.com/software/rtlsdr-scanner software.
viraptor 10y ago
https://learn.adafruit.com/freq-show-raspberry-pi-rtl-sdr-scanner/overview https://learn.adafruit.com/freq-show-raspberry-pi-rtl-sdr-sc...

leetbulb 10y ago

The article states that they used "a Radar Engineers 240A Noise Signature Receiver and UHF Yagi antenna to survey the affected block." Looks like a somewhat portable device (MODEL 243): http://www.radarengineers.com/rfitvi.htm http://www.radarengineers.com/rfitvi.htm Although it's probably going to cost you $5-10k USD. Pretty easy to hook up a RTL-SDR ($10) to a cheap Android tablet loaded with SDR Touch for simple surveying.

tzs 10y ago
I tried to get a price check by dropping "Radar Engineers 240A Noise Signature Receiver" into Google's shopping search, and for some reason all it gave me was one result: a "My Little Pony Friendship is Magic Guardians of Harmony Fan Series Figure - Princess Celestia" from Toys'R'Us. Google is very weird sometimes. Note: I have never watched "My Little Pony", collected anything related, visited any My Little Pony fan sites, read any My Little Pony fan fiction (not even accidentally, via crossovers from fandoms whose fiction I do read), or done anything else to show any interest whatsoever in My Little Pony. Google has a ton of information about me with regards to things I might actually buy, so why the heck did they pick My Little Pony? (Heck, I'm pretty sure they have figure out that I have a ham license...surely they have something more relevant for me than My Little Pony).
- dekhn 10y ago
  I get the same results so I let Google know the results weren't correct. If you drop any one word from the query, you get better results.
- i_are_smart 10y ago
  Just one result? I wonder if it was one of their plant results. I've heard rumors of Google seeding some (just a few) obscured google searches with totally irrelevant results, so they can catch competitors scraping results from their site.
- KMag 10y ago
  Back when I worked at Google on the indexing system, the guy who sat next to me introduced http://www.nextthing.org/archives/2006/10/26/rolling-garfield-ninja-turtles http://www.nextthing.org/archives/2006/10/26/rolling-garfiel... . In his defense, it was someone else's code that he started using more broadly, and there was a latent bug in the third person's code that didn't special-case a sentinel value used for one of the similarity metrics. So, he added some analysis, and all of a sudden Google thought all of the pages that didn't have this similarity metric calculated were all extremely similar. Our manager bought him a stuffed Garfield as a "prize" for breaking Google.

fixermark 10y ago

I grew up in a home with an early-model SyQuest cartridge drive hooked to a Macintosh via SCSI. When the rabbit-ears TV in the same room was turned on and tuned to the right frequency, you could hear the leakage from the drive; it sounded like lower-frequency modem chatter. Not entirely sure what part of the drive was leaking that much RF, but I don't think it was intended to work that way.