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Re: Revision E testing

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  • rubines2000
    Hi Scott Is there a chance you will sell also unpopulated pcbs? I would buy one immediately. Cheers Michael OE1MIS ... set ... network, ... easier to ... of an
    Message 1 of 7 , Aug 3, 2007
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      Hi Scott

      Is there a chance you will sell also unpopulated pcbs?
      I would buy one immediately.

      Cheers
      Michael OE1MIS

      --- In tracker2@yahoogroups.com, Scott Miller <scott@...> wrote:
      >
      > I got the first batch of Proto 'E' boards in, and built up six of them
      > for testing. Like Proto 'D', it's the same form factor as the previous
      > revisions but the components are all surface mount, with the exception
      > of the connectors, crystal, and LEDs.
      >
      > Changes from previous revisions include:
      >
      > - No tuning pot. In my testing, I found that there wasn't any real
      > benefit to being able to adjust the RX tuning, compared to having it
      set
      > with a precision resistor to the calculated optimum value. It seems to
      > perform well across the whole temperature range, and it eliminates one
      > of the more failure-prone parts.
      >
      > - Active RX filter. This takes the place of the passive filter
      network,
      > and seems to squeeze a bit more performance out of the demodulator.
      > Proto 'D' had a quad op amp, but Proto 'E' just has a single op amp in
      > an SOT-23 package.
      >
      > - Ferrites on all off-board signals to reduce RFI.
      >
      > - Red and green LEDs in the TX and RX holes instead of pots. A solid
      > green LED on receive, separate from the activity LED, makes it
      easier to
      > see what's going on and frees up the ACT LED for other signals.
      >
      > - Jumper arrangement changed to match the OT1+, with the exception
      of an
      > EQ jumper in place of A1/A2. This eliminates a few assembly steps and
      > takes up less space.
      >
      > So far, performance is looking good. I did discover something
      > interesting - if you remove the 510k resistor, it actually seems to
      > improve RX performance a bit. I haven't confirmed if this works on the
      > previous versions, and testing is inconclusive so far on the T2-135.
      >
      > I was just looking over my test result archives, and it occurs to me
      > that the decode performance is better than any other '2211-based TNC
      > I've seen, so maybe it's time to finally declare it 'good enough' and
      > get this thing in production!
      >
      > Scott
      >
    • Chris Kantarjiev
      ... Um, do tell. I d love to do anything I can to improve the receive performance of the Proto C at CDRVLY; it s in a rather marginal location, but the only
      Message 2 of 7 , Aug 3, 2007
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        >
        >
        > So far, performance is looking good. I did discover something
        > interesting - if you remove the 510k resistor, it actually seems to
        > improve RX performance a bit. I haven't confirmed if this works on the
        > previous versions, and testing is inconclusive so far on the T2-135.

        Um, do tell. I'd love to do anything I can to improve the receive
        performance of the Proto C at CDRVLY; it's in a rather
        marginal location, but the only igate in "sight" of the valley.

        73 de chris K6DBG
      • Curt, WE7U
        ... I was thinking the same thing... But don t want to take a bunch of Scott s time tweaking the old units to maximize performance. If there are easy tweaks
        Message 3 of 7 , Aug 3, 2007
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          On Fri, 3 Aug 2007, Chris Kantarjiev wrote:

          > Um, do tell. I'd love to do anything I can to improve the receive
          > performance of the Proto C at CDRVLY; it's in a rather
          > marginal location, but the only igate in "sight" of the valley.

          I was thinking the same thing... But don't want to take a bunch of
          Scott's time tweaking the "old" units to maximize performance.

          If there are easy tweaks that would translate to the Proto-A or
          Proto-C units, I'd like to hear about them.

          --
          Curt, WE7U: <www.eskimo.com/~archer/> XASTIR: <www.xastir.org>
          "Lotto: A tax on people who are bad at math." -- unknown
          "Windows: Microsoft's tax on computer illiterates." -- WE7U
          The world DOES revolve around me: I picked the coordinate system!
        • Scott Miller
          You can try clipping the 510k resistor, see if that makes any difference. Also, I replaced the 51k resistor with 100k and it seemed to make a slight
          Message 4 of 7 , Aug 3, 2007
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            You can try clipping the 510k resistor, see if that makes any
            difference. Also, I replaced the 51k resistor with 100k and it seemed
            to make a slight improvement. Both of those seem to affect the slew
            rate on the output of the 2211's FSK comparator.

            Scott

            Curt, WE7U wrote:
            >
            >
            > On Fri, 3 Aug 2007, Chris Kantarjiev wrote:
            >
            > > Um, do tell. I'd love to do anything I can to improve the receive
            > > performance of the Proto C at CDRVLY; it's in a rather
            > > marginal location, but the only igate in "sight" of the valley.
            >
            > I was thinking the same thing... But don't want to take a bunch of
            > Scott's time tweaking the "old" units to maximize performance.
            >
            > If there are easy tweaks that would translate to the Proto-A or
            > Proto-C units, I'd like to hear about them.
            >
            > --
            > Curt, WE7U: <www.eskimo.com/~archer/> XASTIR: <www.xastir.org>
            > "Lotto: A tax on people who are bad at math." -- unknown
            > "Windows: Microsoft's tax on computer illiterates." -- WE7U
            > The world DOES revolve around me: I picked the coordinate system!
            >
            >
          • Scott Miller
            I d rather not. Mostly because of the documentation and support requirements, but you d also have to hit 3 or 4 different distributors to get the required
            Message 5 of 7 , Aug 3, 2007
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              I'd rather not. Mostly because of the documentation and support
              requirements, but you'd also have to hit 3 or 4 different distributors
              to get the required parts if you go by my BOM, or you'd have to find
              substitutes. You'd also need a MON08 pod to program the chip once the
              board is assembled.

              Oh yeah, that's another change I forgot to mention. Proto D and the
              T2-135 both have in-circuit programming connectors, but Proto E is the
              first board with a standard MON08 16-pin header, so you can use it with
              a debug pod without an adapter. Not that anyone aside from me is
              necessarily going to use it, but it's there.

              Scott

              rubines2000 wrote:
              >
              >
              > Hi Scott
              >
              > Is there a chance you will sell also unpopulated pcbs?
              > I would buy one immediately.
              >
              > Cheers
              > Michael OE1MIS
              >
              > --- In tracker2@yahoogroups.com <mailto:tracker2%40yahoogroups.com>,
              > Scott Miller <scott@...> wrote:
              > >
              > > I got the first batch of Proto 'E' boards in, and built up six of them
              > > for testing. Like Proto 'D', it's the same form factor as the previous
              > > revisions but the components are all surface mount, with the exception
              > > of the connectors, crystal, and LEDs.
              > >
              > > Changes from previous revisions include:
              > >
              > > - No tuning pot. In my testing, I found that there wasn't any real
              > > benefit to being able to adjust the RX tuning, compared to having it
              > set
              > > with a precision resistor to the calculated optimum value. It seems to
              > > perform well across the whole temperature range, and it eliminates one
              > > of the more failure-prone parts.
              > >
              > > - Active RX filter. This takes the place of the passive filter
              > network,
              > > and seems to squeeze a bit more performance out of the demodulator.
              > > Proto 'D' had a quad op amp, but Proto 'E' just has a single op amp in
              > > an SOT-23 package.
              > >
              > > - Ferrites on all off-board signals to reduce RFI.
              > >
              > > - Red and green LEDs in the TX and RX holes instead of pots. A solid
              > > green LED on receive, separate from the activity LED, makes it
              > easier to
              > > see what's going on and frees up the ACT LED for other signals.
              > >
              > > - Jumper arrangement changed to match the OT1+, with the exception
              > of an
              > > EQ jumper in place of A1/A2. This eliminates a few assembly steps and
              > > takes up less space.
              > >
              > > So far, performance is looking good. I did discover something
              > > interesting - if you remove the 510k resistor, it actually seems to
              > > improve RX performance a bit. I haven't confirmed if this works on the
              > > previous versions, and testing is inconclusive so far on the T2-135.
              > >
              > > I was just looking over my test result archives, and it occurs to me
              > > that the decode performance is better than any other '2211-based TNC
              > > I've seen, so maybe it's time to finally declare it 'good enough' and
              > > get this thing in production!
              > >
              > > Scott
              > >
              >
              >
            • dk7xe
              Hi Scott, all, ... on the ... anyone who can confirm that removing the 510k brings really RX performance improvement on the older revisions? BTW: got my 2 OT2
              Message 6 of 7 , Aug 17, 2007
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                Hi Scott, all,
                > >
                > > So far, performance is looking good. I did discover something
                > > interesting - if you remove the 510k resistor, it actually seems to
                > > improve RX performance a bit. I haven't confirmed if this works
                on the
                > > previous versions, and testing is inconclusive so far on the T2-135.
                >
                > Um, do tell. I'd love to do anything I can to improve the receive
                > performance of the Proto C at CDRVLY; it's in a rather
                > marginal location, but the only igate in "sight" of the valley.
                >
                > 73 de chris K6DBG
                >
                anyone who can confirm that removing the 510k brings really RX
                performance improvement on the older revisions?

                BTW: got my 2 OT2 revD kits on Tuesday. Did assembly of one in a 2
                hour Morning session before going to work on Wed. Everything is
                working perfectly (see http://map.findu.com/dk7xe-8). Really a great
                device.

                73' Gerald
                dk7xe/oe6dld
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