amazing!
Mystery signal from a helicopter
31–40 of 83 posts
Re: Mystery signal from a helicopter
#32Anyone else see the cop hit him @ https://www.youtube.com/watch?v=TCKRe4jJ0Qk#t=1140 (19min)?
Re: Mystery signal from a helicopter
#33I'd had a copy of her dialup decoded poster on my wall for a while; forgot where I found it but it was immediately something I wanted to hang up... glad to see its being monetized via poster sales, its quite a lovely work of art. Of course, I also find chip tape outs beautiful, much to my wife's dismay. http://vlsiweb.stanford.edu/~jaeha/chip_gallery.html
It's sold here:
http://www.redbubble.com/people/windytan/works/9934517-the-s...
Re: Mystery signal from a helicopter
#34Another cool thing is that the author of Redis made a decoder for ADS-B to decode aircraft transponder signals: https://github.com/antirez/dump1090
Re: Mystery signal from a helicopter
#35Earlier quoted context omitted.
Not really a hack. Subcarriers are how they added color to TV, stereo to FM radio, and so on. WWV/WWVH also sends machine-readable time codes at 100Hz like this.
Indeed--it was more of a hack sixty years ago perhaps. Since then, similar tricks have been used for closed captions, Dolby surround (the original kind), Radio Data System (which puts song names on your car dashboard via FM radio), TV Second Audio Program (listen to shows dubbed in a second language, just press the SAP button on your ancient high-end TV!)....
Wow. I always thought SAP stood for Spanish Audio Program. TIL.
Re: Mystery signal from a helicopter
#36I love this:
Several people in the restaurant were waiting for orders with their similar devices, which suggested to me this could be a pager system of some sort. Turning the receiver over, we see stickers with interesting information, including a UHF carrier frequency. For this kind of situations I often carry my RTL2832U-based television receiver dongle with me (the so-called rtl-sdr).
I knew I was forgetting something.
Re: Mystery signal from a helicopter
#37Oona's work is always amazing. Loads of interesting hardware stuff in her blog. I wish I would be better at some mechanical engineering/electrical engineering stuff, my work is mostly web-related or big data stuff, never really get my hands dirty :(
You can basically reverse those terms for me. I'm a mech engineer who wished he knew more/was better at the web-dev / big data stuff.
Sounds like you guys should be friends.
Re: Mystery signal from a helicopter
#38Nice bit of reverse-engineering, and an impressive hack from whoever built the system.
Not really a hack. Subcarriers are how they added color to TV, stereo to FM radio, and so on. WWV/WWVH also sends machine-readable time codes at 100Hz like this.
>Subcarriers are how they added [...] stereo to FM radio...
Set your time machine for 1958, or follow this link [0] to see how RCA did both FM stereo (throughout the article they call it "multiplex") and 67 KHz "SCA" subcarriers. Admire the awesome 5KW FM transmitter cabinetry and transformer shielding.
Re: Mystery signal from a helicopter
#39I need to learn HW.
Could someone detail more information about the tools she used?
Re: Mystery signal from a helicopter
#40I love this: Several people in the restaurant were waiting for orders with their similar devices, which suggested to me this could be a pager system of some sort. Turning the receiver over, we see stickers with interesting information, including a UHF carrier frequency. For this kind of situations I often carry my RTL2832U-based television receiver dongle with me (the so-called rtl-sdr). I knew I was forgetting somet…
http://www.oz9aec.net/index.php/gnu-radio/gnu-radio-blog/464...
I think this is what she was talking about? Note to self: buy one! :D