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RE: [softrock40] No. 5328 - EMU 0204 module

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  • Peter LB0K
    I purchased an EMU 0204 just before Xmas, and quickly came around to liking the 192KHz display and the seamless way it is tied in with HDSRD. This is the
    Message 1 of 1 , Feb 25, 2013
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      I purchased an EMU 0204 just before Xmas, and quickly came around to liking
      the 192KHz display and the seamless way it is tied in with HDSRD. This is
      the programme I'm using at the moment.
      Sensitivity is good and noise level very acceptable.
      While I haven't run any measurements or exacting tests yet, I have
      experienced that balancing the L and R (or I& Q) channels can be slightly
      touchy.

      Peter, LB0K

      -----Original Message-----
      From: softrock40@yahoogroups.com [mailto:softrock40@yahoogroups.com]
      Sent: 25. februar 2013 19:22
      To: softrock40@yahoogroups.com
      Subject: [softrock40] Digest Number 5328

      There are 3 messages in this issue.

      Topics in this digest:

      1a. E-MU 0204 USB 2.0
      From: pmackanos
      1b. Re: E-MU 0204 USB 2.0
      From: AK4ZW.net

      2a. Re: Anomalous R 32 and R 33 voltage versus frequency values
      From: Paul Marbourg


      Messages
      ________________________________________________________________________
      1a. E-MU 0204 USB 2.0
      Posted by: "pmackanos" k2db@... pmackanos
      Date: Mon Feb 25, 2013 7:42 am ((PST))

      Is anyone using one of these 192 Khz cards , if so how are they working for
      you. We want to put a skimmer up for 6 meters and cover 50.000 - 50.192
      We will be using the Ensemble VHF Receiver.
      Any info or feedback on any 192 Khz card will be welcomed.
      Paul K2DB






      Messages in this topic (2)
      ________________________________________________________________________
      1b. Re: E-MU 0204 USB 2.0
      Posted by: "AK4ZW.net" jhw@... ak4zw
      Date: Mon Feb 25, 2013 7:59 am ((PST))

      It works great and you get the full 192k of scope.

      Sent From My iPhone

      On Feb 25, 2013, at 10:42 AM, "pmackanos" <k2db@...> wrote:

      > Is anyone using one of these 192 Khz cards , if so how are they working
      for you. We want to put a skimmer up for 6 meters and cover 50.000 - 50.192
      > We will be using the Ensemble VHF Receiver.
      > Any info or feedback on any 192 Khz card will be welcomed.
      > Paul K2DB
      >
      >




      Messages in this topic (2)
      ________________________________________________________________________
      ________________________________________________________________________
      2a. Re: Anomalous R 32 and R 33 voltage versus frequency values
      Posted by: "Paul Marbourg" wn7t@... wn7t_paul
      Date: Mon Feb 25, 2013 8:58 am ((PST))

      Thanks for the reply, Alan. Do you think this is a part specific problem
      that may improve by swapping in another FST3253? Or, is this a general
      device/layout problem that is inescapable?
      I built a NorCal 2030 that used discrete architecture for each 90 degrees of
      wave sampling and combined wave phase externally for IQ generation. It is a
      sweet implementation straight from the inventor's bench.

      Perhaps this or even the double balanced QSD mixer approach would have
      yielded truer quadrature phase and amplitude relationships over the softrock
      ensemble's frequency domain.

      73 & thanks again, Alan
      Paul WN7T
      Sent from my iPhone

      On Feb 25, 2013, at 12:00 AM, Alan <alan4alan@...> wrote:

      >
      > ----- Original Message -----
      > Subject: [softrock40] Anomalous R 32 and R 33 voltage versus frequency
      values
      >
      > > Hello group. After assembling my ensemble 2 receiver, I tested the
      voltages on resistors R32 and R33 versus frequency. The R32
      > > voltage values changed considerably, while the voltage vs frequency for
      R33 remained very close to the nominal 2.50 volts. The V
      > > vs Freq remained within 0.3 V for R32 & R33 up until filter bands 2&3,
      when they began to diverge. There was a big broad dip
      > > between 8 MHz & 16 MHz bottoming at about 1.83 V @ 13.2 MHz for R32. R33
      @ this freq was 2.42 V on a Fluke 289 VOM.
      > >
      > > At 16Hz, R32 = 1.86 V, dropping from 2.18 V as the Freq passed into
      filter band 3.
      > >
      >
      > Paul,
      >
      > In fact this is not unusual. It is said to be due to a slight imbalance of
      stray capacitance in the mixer.
      >
      > > All other voltages are normal. The receiver works very well on the lower
      bands, but degrades with respect image suppression on 20
      > > meters and above.
      > >
      > > I reflowed T3's solder points to no avail. All pin/pad voltages are
      nominal. Soldier joints look good. Clock performance okay on
      > > my Tek 454 scope.
      > >
      >
      > Uncorrected image rejection may reduce at higher frequencies due to them
      being more affected by stray capacitance and tolerances.
      >
      > 73 Alan G4ZFQ
      >
      >




      Messages in this topic (3)





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