Saturday, October 21, 2017

Stupidity on TV

My wife was watching a show called "Chicago Fire" where some people, including an off duty paramedic, were trapped in a building collapse of a parking garage. One of the vehicles had a CB radio in it. The trapped people were listening to the CB, and heard the rescuers on their radios outside saying they were pulling back.

This is stupid. CB radios operate in the 11 meter band, meaning that the wavelength is about 11 meters. That makes the frequency near 27 mHz. This band is exclusively used for CB radios. The signal is an AM analog signal.

Public safety radios are allocated different bands. Chicago is operating in the 460 mHz band, and they are using FM digital signals. There are some channels in Chicago that are analog, but they are still in the 460 mHz band.

This requires different radios, different antennas, and the two are nowhere near compatible.

In short, there is NO WAY that an AM CB radio in the 27mHz band can receive an FM digital signal in the 460 mHz band. 

3 comments:

  1. Just like all guns are autos, and scary, so all radios can hear and demod anything...

    whatever moves the plot along...

    n

    ReplyDelete
  2. Added- I'm reasonably certain that if anyone did raise the issue, they were shouted down and assured that no one in the audience would know.

    I recently was talking about the importance of radio in today's world and got nothing but blank stares of befuddlement when I told the person that their cell phone was a radio, and in fact had between 3 and 9 radios in it. This fairly intelligent person had NO IDEA that cell phones worked with radio, nor wifi, nor bluetooth. I didn't even get to NFC or that there are multiple radios for the different bands of cell service.

    Wireless has lost its meaning as a word and is just a noise people hear.

    n

    ReplyDelete
  3. Little late to the party, but I know a few people up here in Maine who just got combo CB/scanners in their trucks

    ReplyDelete

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