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Fw: [kalamazoohamradio] FDMDV plus Video

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  • Tom KD8DEG
    ... From: Bob, K8LR To: Bob Tinney Sent: Saturday, February 25, 2012 7:47 PM Subject: [kalamazoohamradio] FDMDV plus Video Hi, The first YouTube link in the
    Message 1 of 1 , Feb 25, 2012
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      ----- Original Message -----
      From: Bob, K8LR
      Sent: Saturday, February 25, 2012 7:47 PM
      Subject: [kalamazoohamradio] FDMDV plus Video

       

      Hi,
       
      The first YouTube link in the following info not only shows some experimental video that is being transmitted with digitalized audio over SSB, but it also shows a substantial improvement in the analog quality of the audio output of the new digital algorithm.
       

      Bob, K8LR, tinneyb@...
      ----- Original Message -----
      Sent: Saturday, February 25, 2012 6:11 PM
      Subject: [digitalvoice] Re: FDMDV plus Video

      Hello all,

      My previous post (11/1/11) introduced "FDMDV plus Video", which adds video to the FDMDV signal.

      The early version of the video software had a problem with corruption of the FDMDV signal by the adjacent video subcarriers.  An update to the video software corrects this problem by changing the video subcarrier spacing from 43.0664 Hz to 37.5 Hz, exactly half the spacing of the FDMDV subcarriers (thus retaining orthogonality in the composite signal).

      I've posted a demo screenshot video of the new version to YouTube at:

      http://www.youtube.com/watch?v=StQ_OIwocFU

      73, Rick, WA6NUT

      On Tuesday, November 1, 2011 11:29:09 AM UTC-6, wa6nut wrote:
        Hello all,
       
      Group members who use FDMDV may be interested in an experimental technique that adds simultaneous video to the voice signal.
       
      The technique, known as "FDMDV plus Video", provides low-resolution video (36 lines) at 1 frame/sec (like surveillance video).  The video software is a modified version of ZL2AFP's "Analog OFDM" NBTV.  The video software is run simultaneously with HB9TLK's software currently used for FDMDV.
       
      Separate PC's are used for transmitting and receiving (I use laptop PC's with 1.6 GHz minimum clock speed).
       
      The 15-subcarrier FDMDV signal is increased to 64 subcarriers total, requiring a baseband bandwidth from 0.38 to 3.7 kHz for transmitting and receiving (good with newer Ten Tec, FlexRadio and some other HF transceivers).  Unlike FDMDV alone, the operator should not transmit FDMDV plus Video unless all frequencies from 14236 to 14240 kHz are checked and found not to be in use!
       
      The signal has a high peak-to-average power ratio (PAPR), and requires high linearity in the transceiver's AF and RF transmitting stages.  Depending on your transceiver, external amplifiers may be required to obtain the required linearity.  I use a PA-100 and HF Packer 2 linear from HF Projects (K5OOR), giving 20-30 watts output (the HF Packer has the PSU-36V mod for operation from 36Vdc).
       
      Tony, K2MO, has included PathSim simulations for the FDMDV plus Video signal (without voice) at his YouTube pages:
       
       
       
      The simulations are computer-to-computer, and show the effects of propagation on the video portion of the FDMDV plus Video signal.  Because an actual RF link is not used for the simulation, the effects of frequency drift in the transmitter and receiver are not simulated.  Also, because the video software is run without the FDMDV software, the effects of interaction between the video and FDMDV subcarriers are not simulated.
       
      Software and information on FDMDV plus Video (an 840Kb zipped folder) can be downloaded from:
       
       
       
      Read the text file "FDMDV plus Video Info" first.
       
      More information is found at:
       
       
      If you're interested, you're invited to join the Yahoo! group.
       
       73, Rick Peterson, WA6NUT
       


       


        

       


      On Tuesday, November 1, 2011 11:29:09 AM UTC-6, wa6nut wrote:
        Hello all,
       
      Group members who use FDMDV may be interested in an experimental technique that adds simultaneous video to the voice signal.
       
      The technique, known as "FDMDV plus Video", provides low-resolution video (36 lines) at 1 frame/sec (like surveillance video).  The video software is a modified version of ZL2AFP's "Analog OFDM" NBTV.  The video software is run simultaneously with HB9TLK's software currently used for FDMDV.
       
      Separate PC's are used for transmitting and receiving (I use laptop PC's with 1.6 GHz minimum clock speed).
       
      The 15-subcarrier FDMDV signal is increased to 64 subcarriers total, requiring a baseband bandwidth from 0.38 to 3.7 kHz for transmitting and receiving (good with newer Ten Tec, FlexRadio and some other HF transceivers).  Unlike FDMDV alone, the operator should not transmit FDMDV plus Video unless all frequencies from 14236 to 14240 kHz are checked and found not to be in use!
       
      The signal has a high peak-to-average power ratio (PAPR), and requires high linearity in the transceiver's AF and RF transmitting stages.  Depending on your transceiver, external amplifiers may be required to obtain the required linearity.  I use a PA-100 and HF Packer 2 linear from HF Projects (K5OOR), giving 20-30 watts output (the HF Packer has the PSU-36V mod for operation from 36Vdc).
       
      Tony, K2MO, has included PathSim simulations for the FDMDV plus Video signal (without voice) at his YouTube pages:
       
       
       
      The simulations are computer-to-computer, and show the effects of propagation on the video portion of the FDMDV plus Video signal.  Because an actual RF link is not used for the simulation, the effects of frequency drift in the transmitter and receiver are not simulated.  Also, because the video software is run without the FDMDV software, the effects of interaction between the video and FDMDV subcarriers are not simulated.
       
      Software and information on FDMDV plus Video (an 840Kb zipped folder) can be downloaded from:
       
       
       
      Read the text file "FDMDV plus Video Info" first.
       
      More information is found at:
       
       
      If you're interested, you're invited to join the Yahoo! group.
       
       73, Rick Peterson, WA6NUT

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