That was a verry nice compressed talk detailing the first issues to deal with using DVBT sticks for passive radar. This subject has intreged me for way over ten years and yet only now i'm trying to implement such a thing myselve.
I didn't quite follow what was meant about using an oscilloscope for 100x sample rate... Is he suggesting sampling the downconverted complex baseband this way?
I think this is a great achievement and there must be some fields in technology where this can be very useful, like espionage or warfare. There are also some limits, for instance when the received signal suddenly is being stopped for any reason, there is at the same time no passive RADAR image anymore. The classic active RADAR is much more reliable.
Thats why for military applications still a (expendable) transmitter is used, however on a seperate location. This avoids detection or location of the radar station.
But by using active RADAR you are telling everyone your exact position. And Chances are that they can detect your RADAR from much farther away than you can look with your own RADAR. Also, Passive RADARs powered by broadcast FM were already used in the 1930s
Wait, why is the bandwidth important for the resolution of static targets? Why is it a limiting factor for that, when the reference signal doesn’t even emit anything wider than a few kHz?
The signal you'r receiving is 'modulated' by the reflections. the more the phase difference, the more resolution, but also the more bandwidth. Otherwise said. the resuliotion is determt by the wave length.. the higher the resolution, the smaller the wavelength, so the higher the frequenty aka bandwidth. to bad... high resolution radar is not (yett) for the el-cheapo hobbyworld. Still it is cool (and not at all to easy) to play with
Can the tuner IC pll reference crystal pins be bypassed to use an external LO? Its not on the the data sheet, it a manufacturer test, it insider information. This will solve the phase coherent problem.
That was a verry nice compressed talk detailing the first issues to deal with using DVBT sticks for passive radar. This subject has intreged me for way over ten years and yet only now i'm trying to implement such a thing myselve.
how are the results?
I didn't quite follow what was meant about using an oscilloscope for 100x sample rate... Is he suggesting sampling the downconverted complex baseband this way?
I think this is a great achievement and there must be some fields in technology where this can be very useful, like espionage or warfare. There are also some limits, for instance when the received signal suddenly is being stopped for any reason, there is at the same time no passive RADAR image anymore. The classic active RADAR is much more reliable.
Thats why for military applications still a (expendable) transmitter is used, however on a seperate location.
This avoids detection or location of the radar station.
But by using active RADAR you are telling everyone your exact position. And Chances are that they can detect your RADAR from much farther away than you can look with your own RADAR. Also, Passive RADARs powered by broadcast FM were already used in the 1930s
Wait, why is the bandwidth important for the resolution of static targets? Why is it a limiting factor for that, when the reference signal doesn’t even emit anything wider than a few kHz?
The signal you'r receiving is 'modulated' by the reflections. the more the phase difference, the more resolution, but also the more bandwidth.
Otherwise said. the resuliotion is determt by the wave length.. the higher the resolution, the smaller the wavelength, so the higher the frequenty aka bandwidth.
to bad... high resolution radar is not (yett) for the el-cheapo hobbyworld.
Still it is cool (and not at all to easy) to play with
multiple receiver with a two mega hetz bandwidth and power of four thousand kilowatt
Can the tuner IC pll reference crystal pins be bypassed to use an external LO? Its not on the the data sheet, it a manufacturer test, it insider information. This will solve the phase coherent problem.
It's easyer to use a different solution like a usrp... maybe a plutoSDR can be modified
Cheat and convert the received signal for a fish finder with sidescan or 360. Much greater clarity.