.9ghz Security Camera signal

Discussion in 'VHF/UHF - 50Mhz and Beyond' started by KK6WKK, Dec 6, 2015.

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  1. KK6WKK

    KK6WKK Ham Member QRZ Page

    Yesterday I was given an old Gateway Server with Xeon CPU and 4 HDD scsi array along with a 60 inch plasma screen with vga/bnc inputs and a wireless security camera Astak CM 918T 900mhz wireless night vision color camera. I would like to use this on my robot and pipe the data back to my PC and openCV. Unfortunately the bandwidth is to wide for my dongle :/.

    There are white and yellow wires along with the 12v black and red, the camera says NTSC... I would suppose these are analog hook ups but when I probe them with my DSO via black as ground and yellow and white as the signal nothing changes when I put my fingre over the camera. Although I do see changes in the spectrum when I do this, so im not sure the thing works and I dont know how to even get it apart without a dremmel and angle grinder....

    I had to e-mail the company for the manual have not heard back I dont know if I will but I was hoping someone with better radio eyes could give me a start. I don't recognize modulations by eye yet. I would think this is FM but I guess it could be AM and it is 14mhz wide at 917 to 931mhz at least that is the straight green/blue in the water fall.

    [​IMG]

    So im thinking I first need to figure out modulations, then find some TI chip where I can get about 20mhz bandwidth in the subGhz region, and then next demodulate the AM/FM whatever, and lastly demodulate NTSC signal?

    Im sure this is not the regular QRZ type questions but im not sure where there is a device hacking forum for SDR lol :).
     
  2. KA9JLM

    KA9JLM Ham Member QRZ Page

    NTSC broadcast is sideband for video and FM for audio. 6 meg bandwidth per channel.

    The dongles are made for video in the first place. Just use one that does NTSC in its Virgin mode. :)

    Have Fun.

    P.S. QRZ does not allow Hacking Talk unless it is for Experimental Purposes only. :D
     
    Last edited: Dec 6, 2015
  3. KK6WKK

    KK6WKK Ham Member QRZ Page

    Well were expermenting with piping a wireless feed to a powerfull imaging computer! No dirty black hat tricks... just want to use the camera in a different way than intended.

    So they make a dongle for ntsc recption at 900mhz?? I had no idea... id even thought of ripping an old tv apart for thevdemodulator... although im not sure how id use that as an interface to my pc. I know all the SDR dongles ar for DAB or some non american broadcasts but i would have thought that when the us killed analog tv anything off the shelf to decode over the air ntsc would have been obsolete. Ill do a search, right now im on a lunch but if you could provide a link to one of the devices your talking about id be greatly intrested.
     
  4. KA9JLM

    KA9JLM Ham Member QRZ Page

    It would need to be one that covers the Higher Cable channels. Finding one that does NTSC should be no problem.

    The top of the Cable TV band is around 1 gig. Some VCR cable tuners may work, And they have a demodulator.

    Some of the old Radio Shack and X10 Video senders work on 900 also.

    Enjoy.
     
  5. KK4YWN

    KK4YWN Ham Member QRZ Page

    which dongle? i think the sdrplay has 10-12mhz bandwidth. i think the other dongles are limited to 2mhz?
     

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