The RadioInstigator: A $150 Signals Intelligence Platform
1–10 of 23 posts
Re: The RadioInstigator: A $150 Signals Intelligence Platform
#2Wait, an antenna connected to the GPIO pin on a RaspberryPi for transmissions? Correct me if I'm wrong, but doesn't the Pi output square waves, that would cause harmonics if transmitted?
Re: The RadioInstigator: A $150 Signals Intelligence Platform
#3Wait, an antenna connected to the GPIO pin on a RaspberryPi for transmissions? Correct me if I'm wrong, but doesn't the Pi output square waves, that would cause harmonics if transmitted?
You need a band-filter. In the simplest case, the antenna is one. I haven't looked into it in more detail, but I would guess that they exploit the higher harmonics of the square wave to actually reach the 1.5GHz.
Re: The RadioInstigator: A $150 Signals Intelligence Platform
#4Wait, an antenna connected to the GPIO pin on a RaspberryPi for transmissions? Correct me if I'm wrong, but doesn't the Pi output square waves, that would cause harmonics if transmitted?
Yep, if you know the carrier frequency of your mobile you can jam it from a few feet away with those harmonics.
Re: The RadioInstigator: A $150 Signals Intelligence Platform
#5Wait, an antenna connected to the GPIO pin on a RaspberryPi for transmissions? Correct me if I'm wrong, but doesn't the Pi output square waves, that would cause harmonics if transmitted?
Yes, the Pi only has digital pins. I didn't really watch the video but I assume any antenna is connected to another board and that board is controlled through the Pi pins.
Actually, looking at the photo of the internals, it looks like the only thing connected to GPIO is the GPS board, all the radio hardware is connected to USB ports.
Re: The RadioInstigator: A $150 Signals Intelligence Platform
#6Wait, an antenna connected to the GPIO pin on a RaspberryPi for transmissions? Correct me if I'm wrong, but doesn't the Pi output square waves, that would cause harmonics if transmitted?
Yes, the Pi only has digital pins. I didn't really watch the video but I assume any antenna is connected to another board and that board is controlled through the Pi pins. Actually, looking at the photo of the internals, it looks like the only thing connected to GPIO is the GPS board, all the radio hardware is connected to USB ports.
He says he uses the GPIO 4 pin[0], and recommends using a bandpass filter
Re: The RadioInstigator: A $150 Signals Intelligence Platform
#7Wait, an antenna connected to the GPIO pin on a RaspberryPi for transmissions? Correct me if I'm wrong, but doesn't the Pi output square waves, that would cause harmonics if transmitted?
With low cost transmit capable SDR's now available, nobody should be transmitting trash from a GPIO pin.
https://www.digikey.com/product-detail/en/analog-devices-inc...
Re: The RadioInstigator: A $150 Signals Intelligence Platform
#8[deleted]
Re: The RadioInstigator: A $150 Signals Intelligence Platform
#9Wait, an antenna connected to the GPIO pin on a RaspberryPi for transmissions? Correct me if I'm wrong, but doesn't the Pi output square waves, that would cause harmonics if transmitted?
There was an old RPi project released a while ago (PiRadio I think?) which simply involved attaching a jump lead to GPIO pin 4 which allowed the transmission of FM radio signals.
It worked on the principal that the Pi had a stupidly powerful clock and thus could be used as a transmitter.
I did a little experiment where I hooked it up to a yagi antenna and asked my dad to set his cars radio to the frequency I set the software to transmit on and drive around the block to test the distance.
Not only did it work well but I think I heard someone listening to the radio in their home near mine open their front door and yell out "who ever is doing that could you please stop it!" as it was interfering/jamming what they were listening to.
I'm definitely checking this project out though, thanks for posting.
Re: The RadioInstigator: A $150 Signals Intelligence Platform
#10Wait, an antenna connected to the GPIO pin on a RaspberryPi for transmissions? Correct me if I'm wrong, but doesn't the Pi output square waves, that would cause harmonics if transmitted?
There was an old RPi project released a while ago (PiRadio I think?) which simply involved attaching a jump lead to GPIO pin 4 which allowed the transmission of FM radio signals. It worked on the principal that the Pi had a stupidly powerful clock and thus could be used as a transmitter. I did a little experiment where I hooked it up to a yagi antenna and asked my dad to set his cars radio to the frequency I set the…
"There was an old RPi project..."
Is this it?
http://icrobotics.co.uk/wiki/index.php/Turning_the_Raspberry...