3 ms·

4 digit code on 144mhz -- just sending a code alone triggers alert? Wouldn't it need a payload to describe the msg?

AdamJacobMuller 9y ago
Likely multiple codes, each one triggers a specific hardcoded message. I'm assuming this was from the past ("when i was a teenager") when the messages were much more generic and fixed than they are today.
- paulie_a 9y ago
  No it was the same 4 codes, and the same message: "loud' It definitely is from my teenage years but whenever I visit folks I drive by that tower a block away. You can tell nothing has been upgraded
  - AdamJacobMuller 9y ago
    This was just a siren then? Makes sense. Smart system, really. Very simple to install/maintain and very simple to have a robust transmitter infrastructure around. If you just substitute your 4-digit code for a longer, say, 64, digit one with some time-based component, and perhaps shift the required frequency too based on time, you actually end up with a very robust very simple system.
    - Double_a_92 9y ago
      https://en.wikipedia.org/wiki/Security_through_obscurity https://en.wikipedia.org/wiki/Security_through_obscurity
      - gnode 9y ago
        I disagree. The frequency hopping would make it harder for a signal jammer to prevent a legitimate transmission. If you can't predict the frequency on which the transmission is being listened for, you'd need to jam a broader spectrum, needing much more power to perform the attack.
phil21 9y ago
He likely means emergency sirens - I also had some friends I'd hang out with as a teenager who figured this out as well. As far as I'm aware this is still the case - but some sites are now encrypted radio. From what I've heard though, that encryption may not be the best implemented in all areas. It was pretty recently someone set off the civil warning sirens in I believe a city in Texas via this method as well. I'd like to say this was a one off experience in my "exploring civil infrastructure" days - but it's really just barely scraping the surface. The state of these systems makes you realize how much civilization is held together with tin cans and duct tape, and how much marketing fluff there truly is out there inspiring false confidence.
paulie_a 9y ago
The payload was the 4 digit code, it was a large tornado warning siren. The msg was "be loud". I lived 300 yards from it, and had a dad with a police scanner. I noticed a pattern after a while... Saturday's they ran some test of the system...4 digits at noon on the radio and a blasting sound would follow

Likely multiple codes, each one triggers a specific hardcoded message. I'm assuming this was from the past ("when i was a teenager") when the messages were much more generic and fixed than they are today.

paulie_a 9y ago
No it was the same 4 codes, and the same message: "loud' It definitely is from my teenage years but whenever I visit folks I drive by that tower a block away. You can tell nothing has been upgraded
- AdamJacobMuller 9y ago
  This was just a siren then? Makes sense. Smart system, really. Very simple to install/maintain and very simple to have a robust transmitter infrastructure around. If you just substitute your 4-digit code for a longer, say, 64, digit one with some time-based component, and perhaps shift the required frequency too based on time, you actually end up with a very robust very simple system.
  - Double_a_92 9y ago
    https://en.wikipedia.org/wiki/Security_through_obscurity https://en.wikipedia.org/wiki/Security_through_obscurity
    - gnode 9y ago
      I disagree. The frequency hopping would make it harder for a signal jammer to prevent a legitimate transmission. If you can't predict the frequency on which the transmission is being listened for, you'd need to jam a broader spectrum, needing much more power to perform the attack.

phil21 9y ago

He likely means emergency sirens - I also had some friends I'd hang out with as a teenager who figured this out as well. As far as I'm aware this is still the case - but some sites are now encrypted radio. From what I've heard though, that encryption may not be the best implemented in all areas. It was pretty recently someone set off the civil warning sirens in I believe a city in Texas via this method as well. I'd like to say this was a one off experience in my "exploring civil infrastructure" days - but it's really just barely scraping the surface. The state of these systems makes you realize how much civilization is held together with tin cans and duct tape, and how much marketing fluff there truly is out there inspiring false confidence.

paulie_a 9y ago

The payload was the 4 digit code, it was a large tornado warning siren. The msg was "be loud". I lived 300 yards from it, and had a dad with a police scanner. I noticed a pattern after a while... Saturday's they ran some test of the system...4 digits at noon on the radio and a blasting sound would follow