4 ms·

I'm assuming he also didn't account for harmonics. It'd be interesting to see how dirty his transmissions made the spectrum.

sokoloff 7y ago
Given that he took out 315MHz in a pretty wide area, I'm wagering he was using a specific 315MHz module and was just transmitting a near-constant signal. (A duty cycle issue rather than a harmonics issue.) Something like this: https://www.aliexpress.com/item/NEW315mhz-rf-Transmitter-and-Receiver-superheterodyne-UHF-ASK-remote-control-Module-Kit-small-size-low-power/32665290214.html https://www.aliexpress.com/item/NEW315mhz-rf-Transmitter-and...
- riskable 7y ago
  Also don't rule out an incredibly poorly made 315Mhz transmitter. Chinese companies will see lots of bad reviews on their 315Mhz breakout board like, "Terrible product! Only works from within like 3 feet from the transmitter." So management gets mad at the engineer (who likely has no formal training or knowledge of FCC regulations) and says, "fix it!" "OK OK I'll just crank up the power!" Version 1.1 of the board is released on AliExpress a week later ("New version of board. We fixed weak signal!"). End users start getting the new board and like magic they can pick up a signal from like a mile away!
  - Cyph0n 7y ago
    Then the FCC comes knocking?
    - colejohnson66 7y ago
      FCC can’t really do anything about a Chinese person selling from China
      - azhenley 7y ago
        They can if someone is importing it.
        ajuc 7y ago
        Most hobbyst (at least where I live) order directly from China on ebay or aliexpress. It's cheapest this way.
        amingilani 7y ago
        That's what I do it almost all my equipment (not US, though)
        Freak_NL 7y ago
        Customs services worldwide probably won't even come close to inspecting even 1% of that unending stream of tiny plastic envelopes containing some sort of electronics heading for thousands of local hobbyists. It's a logistical impossibility.
        ajuc 7y ago
        They could blacklist everything and only pass-through stuff sent by trusted exporters I guess. Check 1% of the packages, if some exporter lied revoke his trusted status. But I highly doubt they will do it :)
      - morpheuskafka 7y ago
        They can send a BOLO to CBP and have the devices seized on import.
        myself248 7y ago
        HAHAHahahahaa. An entire bucket of Chinese electronic components in my living room begs to disagree.
        sokoloff 7y ago

sokoloff 7y ago

Given that he took out 315MHz in a pretty wide area, I'm wagering he was using a specific 315MHz module and was just transmitting a near-constant signal. (A duty cycle issue rather than a harmonics issue.) Something like this: https://www.aliexpress.com/item/NEW315mhz-rf-Transmitter-and-Receiver-superheterodyne-UHF-ASK-remote-control-Module-Kit-small-size-low-power/32665290214.html https://www.aliexpress.com/item/NEW315mhz-rf-Transmitter-and...

riskable 7y ago
Also don't rule out an incredibly poorly made 315Mhz transmitter. Chinese companies will see lots of bad reviews on their 315Mhz breakout board like, "Terrible product! Only works from within like 3 feet from the transmitter." So management gets mad at the engineer (who likely has no formal training or knowledge of FCC regulations) and says, "fix it!" "OK OK I'll just crank up the power!" Version 1.1 of the board is released on AliExpress a week later ("New version of board. We fixed weak signal!"). End users start getting the new board and like magic they can pick up a signal from like a mile away!
- Cyph0n 7y ago
  Then the FCC comes knocking?
  - colejohnson66 7y ago
    FCC can’t really do anything about a Chinese person selling from China
    - azhenley 7y ago
      They can if someone is importing it.
      - ajuc 7y ago
        Most hobbyst (at least where I live) order directly from China on ebay or aliexpress. It's cheapest this way.
        amingilani 7y ago
        That's what I do it almost all my equipment (not US, though)
        Freak_NL 7y ago
        Customs services worldwide probably won't even come close to inspecting even 1% of that unending stream of tiny plastic envelopes containing some sort of electronics heading for thousands of local hobbyists. It's a logistical impossibility.
        ajuc 7y ago
        They could blacklist everything and only pass-through stuff sent by trusted exporters I guess. Check 1% of the packages, if some exporter lied revoke his trusted status. But I highly doubt they will do it :)
    - morpheuskafka 7y ago
      They can send a BOLO to CBP and have the devices seized on import.
      - myself248 7y ago
        HAHAHahahahaa. An entire bucket of Chinese electronic components in my living room begs to disagree.
      - sokoloff 7y ago