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Failing transformers can cause an incredible amount of RF noise. A couple years ago a failing fluorescent light ballast prevented my garage door opener remote f

Failing transformers can cause an incredible amount of RF noise. A couple years ago a failing fluorescent light ballast prevented my garage door opener remote from working until it finally gave out (this was when I discovered it as the cause), and it had enough residual power to maintain the interference for a while even after being turned off.

dsfyu404ed 8y ago
A grocery store has a lot of florescent lights. More opportunities for failure.
- samstave 8y ago
  IS this why cell signal always seem to be horrible in grocery stores (aside from them being large concrete-block buildings?
  - Pharmakon 8y ago
    That, and the automatic door sensors can be quite noisy.
  - Fjolsvith 8y ago
    Steel siding and roofing blocks cell signal, too? My home has aluminum siding and steel roof and until my wife and I got S9's we had horrible reception in the house. Had to install a cell booster with the antenna up on the roof.
    - markdown 8y ago
      > Had to install a cell booster with the antenna up on the roof. Where can I find such a thing?
      - fphhotchips 8y ago
        In Australia the carriers sell them. I'd start there.
        mynameisvlad 8y ago
        I believe all 4 of the major US carriers also sell or even just give them away. It's in their best interest for their customers to have good signal coverage in a place they spend a lot of time in. Although these days, with Wi-Fi calling for voice and Wi-Fi itself for data, the need for these devices is lower and lower.
        markdown 8y ago
        Thanks. Bugger, those prices! https://www.powertec.com.au/mobile-products/signal-repeaters/vodafone-repeaters https://www.powertec.com.au/mobile-products/signal-repeaters...
      - colanderman 8y ago
        I had one of these for a while: https://www.amazon.com/Wilson-Electronics-Signal-Booster-Office/dp/B0014KOB6Y https://www.amazon.com/Wilson-Electronics-Signal-Booster-Off... Worked well enough. Looks like 4G models are more expensive. (No longer need it as I'm with Republic Wireless now.)
        markdown 8y ago
        Thanks
      - swozey 8y ago
        Most cell providers will give you one for a deposit. I know tmobile does for something like $25.
        joecool1029 8y ago
        Ironically the booster that T-Mobile provides causes more issues. Unlike the old ones that brought the signal in from an antenna to the base using some coax, the current models link up the receiver to the amp using unlicensed 5GHZ. This killed my 802.11ac speeds when I had one. T-Mobile will now send a full femtocell that uses your ISP's net and broadcasts both WCDMA and LTE. It's much better.
phirschybar 8y ago
Same thing happened to me recently! :)
vvanders 8y ago
Yeah, in addition most cheap(< $200) wireless modules are pretty susceptible to front end overload. If strong enough the RF noise doesn't even need to be in the same spectrum. Even my 2m Kenwood D710 mobile in my car will break squelch on some drive throughs. Tesla had a similar issue when someone started taking them too close to radio towers up on the hills. Luckily they were able to build a foil shield so they could get the RFID spot to pick them up.
patcheudor 8y ago
Neon sign transformers are routinely the cause of such interference as well: https://www.schneier.com/blog/archives/2016/08/unintentional_d.html https://www.schneier.com/blog/archives/2016/08/unintentional...
throwaway2048 8y ago
AC Linear Transformers effectively are antennas, that is how they induce current in the tapped windings as far as i understand things.
birdman3131 8y ago
We have lights with newer electronic ballasts and some with the old magnetic ballasts. If you take the tracer part of https://www.amazon.com//dp/B0042VII7A/ https://www.amazon.com//dp/B0042VII7A/ you have to be within a few inches to pick up the electronic ballasts. You can pickup the magnetic ones from 10-20 feet away. (We have the LED's to replace them but finding times to do so is a problem.)
- userbinator 8y ago
  It's usually electronic ballasts that cause more interference since they have an oscillator that runs in the high kHz/MHz, while the magnetic ones don't oscillate at more than the 50/60Hz mains frequency.
Tiki 8y ago
(On a much smaller scale) - I had a plasma ball toy as a kid, the kind you put your finger on and the electricity arcs to your finger. One day I broke the glass housing. Curious what would happen, I plugged it in - the radio in the kitchen AND the TV in the living room both simultaneously wouldn't run when the broken plasma bulb was plugged in. I did this several times as a prank on unsuspecting family members and then the unit burned out/wouldn't turn on. I still don't know how dangerous this was to do(if at all).
- epaulson 8y ago
  I have always wanted a plasma globe but have never gotten one because I've been worried about how much radio noise they might generate and if it would interfere with WiFi etc.
- homero 8y ago
  My scale wouldn't record my body fat for months until i turned off my plasma ball and it started working again. I was livid thinking it broke.
- userbinator 8y ago
  The most dangerous part of that would probably be being caught by the FCC.
- borgel 8y ago
  I used to enjoy wrapping a metal slinky around the base of mine. Then whenever I touched metal to it I’d get little sparks. Must have been acting as an antenna, but I wonder what exactly was going on.
  - superkuh 8y ago
    It's acting like a capacitor.

dsfyu404ed 8y ago

A grocery store has a lot of florescent lights. More opportunities for failure.

samstave 8y ago
IS this why cell signal always seem to be horrible in grocery stores (aside from them being large concrete-block buildings?
- Pharmakon 8y ago
  That, and the automatic door sensors can be quite noisy.
- Fjolsvith 8y ago
  Steel siding and roofing blocks cell signal, too? My home has aluminum siding and steel roof and until my wife and I got S9's we had horrible reception in the house. Had to install a cell booster with the antenna up on the roof.
  - markdown 8y ago
    > Had to install a cell booster with the antenna up on the roof. Where can I find such a thing?
    - fphhotchips 8y ago
      In Australia the carriers sell them. I'd start there.
      - mynameisvlad 8y ago
        I believe all 4 of the major US carriers also sell or even just give them away. It's in their best interest for their customers to have good signal coverage in a place they spend a lot of time in. Although these days, with Wi-Fi calling for voice and Wi-Fi itself for data, the need for these devices is lower and lower.
      - markdown 8y ago
        Thanks. Bugger, those prices! https://www.powertec.com.au/mobile-products/signal-repeaters/vodafone-repeaters https://www.powertec.com.au/mobile-products/signal-repeaters...
    - colanderman 8y ago
      I had one of these for a while: https://www.amazon.com/Wilson-Electronics-Signal-Booster-Office/dp/B0014KOB6Y https://www.amazon.com/Wilson-Electronics-Signal-Booster-Off... Worked well enough. Looks like 4G models are more expensive. (No longer need it as I'm with Republic Wireless now.)
      - markdown 8y ago
        Thanks
    - swozey 8y ago
      Most cell providers will give you one for a deposit. I know tmobile does for something like $25.
      - joecool1029 8y ago
        Ironically the booster that T-Mobile provides causes more issues. Unlike the old ones that brought the signal in from an antenna to the base using some coax, the current models link up the receiver to the amp using unlicensed 5GHZ. This killed my 802.11ac speeds when I had one. T-Mobile will now send a full femtocell that uses your ISP's net and broadcasts both WCDMA and LTE. It's much better.

phirschybar 8y ago

Same thing happened to me recently! :)

vvanders 8y ago

Yeah, in addition most cheap(< $200) wireless modules are pretty susceptible to front end overload. If strong enough the RF noise doesn't even need to be in the same spectrum. Even my 2m Kenwood D710 mobile in my car will break squelch on some drive throughs. Tesla had a similar issue when someone started taking them too close to radio towers up on the hills. Luckily they were able to build a foil shield so they could get the RFID spot to pick them up.

patcheudor 8y ago

Neon sign transformers are routinely the cause of such interference as well: https://www.schneier.com/blog/archives/2016/08/unintentional_d.html https://www.schneier.com/blog/archives/2016/08/unintentional...

throwaway2048 8y ago

AC Linear Transformers effectively are antennas, that is how they induce current in the tapped windings as far as i understand things.

birdman3131 8y ago

We have lights with newer electronic ballasts and some with the old magnetic ballasts. If you take the tracer part of https://www.amazon.com//dp/B0042VII7A/ https://www.amazon.com//dp/B0042VII7A/ you have to be within a few inches to pick up the electronic ballasts. You can pickup the magnetic ones from 10-20 feet away. (We have the LED's to replace them but finding times to do so is a problem.)

userbinator 8y ago
It's usually electronic ballasts that cause more interference since they have an oscillator that runs in the high kHz/MHz, while the magnetic ones don't oscillate at more than the 50/60Hz mains frequency.

Tiki 8y ago

(On a much smaller scale) - I had a plasma ball toy as a kid, the kind you put your finger on and the electricity arcs to your finger. One day I broke the glass housing. Curious what would happen, I plugged it in - the radio in the kitchen AND the TV in the living room both simultaneously wouldn't run when the broken plasma bulb was plugged in. I did this several times as a prank on unsuspecting family members and then the unit burned out/wouldn't turn on. I still don't know how dangerous this was to do(if at all).

epaulson 8y ago
I have always wanted a plasma globe but have never gotten one because I've been worried about how much radio noise they might generate and if it would interfere with WiFi etc.
homero 8y ago
My scale wouldn't record my body fat for months until i turned off my plasma ball and it started working again. I was livid thinking it broke.
userbinator 8y ago
The most dangerous part of that would probably be being caught by the FCC.
borgel 8y ago
I used to enjoy wrapping a metal slinky around the base of mine. Then whenever I touched metal to it I’d get little sparks. Must have been acting as an antenna, but I wonder what exactly was going on.
- superkuh 8y ago
  It's acting like a capacitor.