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Re: [softrock40] I-Q signal levels of SR v6.3?

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  • Sid Boyce
    ... The on air signal was around 59+20 dB which is ~0.5mV at the antenna - then I thought the LT6231CS8 gain would achieve a measurable signal on 10mV/div. 73
    Message 1 of 7 , Oct 24, 2009
      On 24/10/09 20:45, Dave - WB6DHW wrote:
      >
      >
      > Sid Boyce wrote:
      >> On 24/10/09 03:51, aa9wqham@... <mailto:aa9wqham%40aol.com> wrote:
      >>
      >>>
      >>>
      >>> Either side should be fine. The voltage might be lower on the other side
      >>> of the resistors because of loading from the sound card but won't make
      >>> any difference measuring phase difference.Tthat won't change on either
      >>> side of the resistor.
      >>>
      >>> Larry W9AMR
      >>>
      >>>
      >> Only problem with Alex's BPF installed, I can't get to the resistors and
      >> at the outputs there is 0V deflection at 0.1V/div both on RX and TX out
      >> of the rig, except on TX I don't get any RF out - suspect a software
      >> problem there as it used to work and I can back off the changes.
      >> 73 ... Sid.
      >>
      >>
      >>> In a message dated 10/23/2009 10:37:15 P.M. Eastern Daylight Time,
      >>> sboyce@... <mailto:sboyce%40blueyonder.co.uk> writes:
      >>>
      >>>
      >>>
      >>> I have been looking at I-Q signals at "AUDIO OUT" on the scope with
      >>> thumping great signals coming in, but I see 0V on my scope set at
      >>> .01V/div and as slow as 0.5 sec. sweep speed. Scope is HP 1725A with HP
      >>> 1Mohm 10:1 probes.
      >>> I was hoping to measure the I-Q phase difference, same on TX.
      >>> Should the measurements be made at the LT6231CS8 outputs ahead of the
      >>> 100 ohm resistors R55 and R56?
      >>> 73 ... Sid.
      >>> --
      >>>
      >>
      >>
      > How much RF are you putting into the antenna input. Unless you're
      > putting a strong signal in, your I/Q output will be microvolts, or at
      > most a few millivolts.
      >
      > Dave - WB6DHW
      > <http://wb6dhw.com <http://wb6dhw.com>>
      >

      The on air signal was around 59+20 dB which is ~0.5mV at the antenna -
      then I thought the LT6231CS8 gain would achieve a measurable signal on
      10mV/div.
      73 ... Sid.
      --
      Sid Boyce ... Hamradio License G3VBV, Licensed Private Pilot
      Emeritus IBM/Amdahl Mainframes and Sun/Fujitsu Servers Tech Support
      Specialist, Cricket Coach
      Microsoft Windows Free Zone - Linux used for all Computing Tasks
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