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2462Re: degrading Si570s?

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  • Henk
    May 1, 2012
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      Hello all,

      I built a LIMA-SDR. In this design by Bernd Wehner
      DL9WB, are 2 fat R's placed on the Si570 to heat the chip up. An NTC is also put on it to control temperature. Interested in LIMA or want to download schematics? Go to http://www.darc.de/distrikte/l/02/sdr/handbuecher/ (German site)

      73 de Henk - Parasetguy
      http://www.paraset.nl/



      --- In powersdr-iq@yahoogroups.com, "The Silver Fox" <alan.r.hill@...> wrote:
      >
      > The documentation implies that the chips are humidity sensitive and that
      > should they misbehave, put them in an oven for a while.
      >
      > 73,
      >
      > Alan - W6ARH
      >
      >
      >
      > From: powersdr-iq@yahoogroups.com [mailto:powersdr-iq@yahoogroups.com] On
      > Behalf Of sv1eia
      > Sent: Tuesday, May 01, 2012 4:29 AM
      > To: powersdr-iq@yahoogroups.com
      > Subject: [powersdr-iq] Re: degrading Si570s?
      >
      >
      >
      >
      >
      > Hi Owen,
      >
      > Yes, I've seen numbers like these, having used more than 20 Si570 here.
      > In the device datasheet
      > -> http://www.silabs.com/Support%20Documents/TechnicalDocs/si570.pdf
      > page 13 on the table item
      > "Internal Crystal Frequency Accuracy", it has 2000 ppm variation on
      > 114.285.000 Hz so that goes if I'm not mistaken to about 228000 max
      > variation, so since you're at about 60000 you're within limits.
      >
      > Most of the times, I've noticed higher variations with CMOS type whereas
      > less variation with LVDS.
      >
      > 73,
      > Christos SV1EIA
      >
      > --- In powersdr-iq@yahoogroups.com <mailto:powersdr-iq%40yahoogroups.com> ,
      > "owen1936" <owen1936@> wrote:
      > >
      > > Over the past few years I've built three or four Si-570-based SDRs. To
      > accurately calibrate them I've used a GPS-stabilized 10mHz reference input
      > to a counter and the Expert/Clock Offset input in PSDR-IQ to correct
      > frequency errors. Up until now I've never had to input any correction
      > greater than -3900. But today in setting up for a possible new radio using
      > PSDR-IQ v1.19.3.15 it required an offset of -60,530 to calibrate!
      > >
      > > I wonder if anybody else has seen this much required correction??
      > >
      > > 73,
      > > Owen
      > >
      >
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