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Re: [tracker2] T2-301 Adjusting Audio Level / RX Sensitivity

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  • Scott Miller
    Hmm. Can you check the connection on the BNC? A few units have had a flaky solder joint there. On the bench they re tested at something like -60 dBm with a
    Message 1 of 2 , Nov 24, 2009
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      Hmm. Can you check the connection on the BNC? A few units have had a
      flaky solder joint there.

      On the bench they're tested at something like -60 dBm with a signal
      source that's just a bunch of copies of the same packet with increasing
      levels of noise. Of course, that doesn't do much to test the RF
      sensitivity of the radio, just the demodulator. I should probably set
      the test set to -105 dBm or so, where I know it should get solid copy if
      it's working right.

      I just copied the test setup I used for the T2-135's, but there testing
      the radio wasn't an issue. I've been trusting the radio manufacturer's
      QA, but it wouldn't cost me anything to crank the signal level way lower
      to weed out any weak ones.

      Scott

      g7iii wrote:
      >
      >
      > Hi All,
      >
      > Is there a pot or two inside the T2-301 where I can adjust the receive
      > audio level being fed into the T2 board ?
      >
      > I'm in a situation where:
      >
      > a) I don't hear many packets on the T2-301
      > b) If I turn PASSALL on, they all come flooding past in various states
      > of corruption
      > c) Plugging the D-710 into the same antenna results in many packets
      > being decoded from far stations (~25 miles plus) as well as near
      > stations (~5 miles)
      > d) I did try an external pre-amp (although admittedly, not mast-head
      > mounted), which did not improve the system at all)
      > e) A Very distant digi can hear me (although it is very high), but I
      > can't hear it (and w/o hearing many packets of course, I suspect the
      > CSMA gets stuffed up and I end up stomping,o r getting stomped on
      >
      > So I'm kinda wondering I have an RX Sensitivity issue, a S/N issue, or
      > if it's a situation where a bit more audio needs to be injected to the
      > T2, and if somehow I can twiddle the two at all ?
      >
      > 73s
      >
      > Iain
      >
      >
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