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Re: [tracker2] AHAB

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  • Jeremy Day
    I guess I should clear up a few things: I meant that the GPS input would be NMEA protocol. Output from the TNC to the radio is (I assume) AX.25 standard. Also,
    Message 1 of 9 , Sep 6, 2007
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      I guess I should clear up a few things:

      I meant that the GPS input would be NMEA protocol. Output from
      the TNC to the radio is (I assume) AX.25 standard.

      Also, by restricted digipeat capability, I mean having the digipeater
      listen only for packets from our chase vehicles, which would (I hope)
      be the only packets on whatever frequency we chose. This frequency
      should be different from the national APRS frequency.

      Thanks to everyone for their input.

      Jeremy Day
      Communications Lead
      Auburn High Altitude Balloon Team
      space.auburn.edu
    • Scott Miller
      Ok. NMEA input is fine, of course. As I mentioned, Garmin binary mode will give you vertical speed, but you ll also get estimated position error rather than
      Message 2 of 9 , Sep 6, 2007
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        Ok. NMEA input is fine, of course. As I mentioned, Garmin binary mode
        will give you vertical speed, but you'll also get estimated position
        error rather than HDOP, and time will be off a bit due to the lack of
        leap second handling in the current firmware.

        You can restrict digipeating by using a non-standard alias. I think I
        used AIR for mine. You just need to set the path appropriately on the
        stations using it.

        And to clarify further on the NMEA thing, all APRS output is going to be
        AX.25 (well, unless you're running PSK31 anyway) - but APRS lets you use
        NMEA or one of three or four other position formats within that AX.25
        packet.

        Scott

        Jeremy Day wrote:
        >
        >
        > I guess I should clear up a few things:
        >
        > I meant that the GPS input would be NMEA protocol. Output from
        > the TNC to the radio is (I assume) AX.25 standard.
        >
        > Also, by restricted digipeat capability, I mean having the digipeater
        > listen only for packets from our chase vehicles, which would (I hope)
        > be the only packets on whatever frequency we chose. This frequency
        > should be different from the national APRS frequency.
        >
        > Thanks to everyone for their input.
        >
        > Jeremy Day
        > Communications Lead
        > Auburn High Altitude Balloon Team
        > space.auburn.edu
        >
      • Bob Burns W9RXR
        ... In the words of Jeff Foxworthy, you have my attention. Tell us more. How frequency agile will these RF boards be? How much current will they draw? What s
        Message 3 of 9 , Sep 7, 2007
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          At 04:25 PM 9/6/2007, Scott Miller wrote:
          >If and when I get a compact transceiver an all-in-one T2 would be a
          >possibility. In fact, I'm doing that with the more expensive
          >commercial 6-watt RF boards.

          In the words of Jeff Foxworthy, you have my attention.

          Tell us more. How frequency agile will these RF boards be? How much
          current will they draw? What's your time line for this project?

          Bob...
        • Scott Miller
          Catching up on email again... The commercial boards will do 136 to 162 MHz in 2.5 kHz steps. Transmitter attack time is under 15 ms. Current drain at 6 watts
          Message 4 of 9 , Sep 18, 2007
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            Catching up on email again...

            The commercial boards will do 136 to 162 MHz in 2.5 kHz steps.
            Transmitter attack time is under 15 ms. Current drain at 6 watts is a
            little over 2 amps. Receive current is about 80 mA.

            They're really not meant for high duty cycles - the PA starts heating up
            really fast. For testing, I've bolted a couple of the largest TO-220
            heatsinks I had on hand to the thing and it does much better - I don't
            have to worry about a software glitch locking it in transmit mode for 20
            seconds and cooking the board.

            Scott

            Bob Burns W9RXR wrote:
            >
            >
            > At 04:25 PM 9/6/2007, Scott Miller wrote:
            > >If and when I get a compact transceiver an all-in-one T2 would be a
            > >possibility. In fact, I'm doing that with the more expensive
            > >commercial 6-watt RF boards.
            >
            > In the words of Jeff Foxworthy, you have my attention.
            >
            > Tell us more. How frequency agile will these RF boards be? How much
            > current will they draw? What's your time line for this project?
            >
            > Bob...
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