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Using rx ensemble II at Intermediate Frequencies.

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  • rahew1
    Hi all I am currently using an rx ensemble (HF) to tap into the IF of various valve receivers including a Drake R4B 5.645Mhz and a homebrew dual conversion at
    Message 1 of 2 , Mar 1, 2013
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      Hi all

      I am currently using an rx ensemble (HF) to tap into the IF of various valve receivers including a Drake R4B 5.645Mhz and a homebrew dual conversion at 1.62Mhz (1st IF).Both seem to work very well tapping in before the IF Filters allowing me "see" the whole band by setting the ensemble to 5.6 and 1.6Mhz respectively.Im not sure how to make meaningful snr measurements but the rocky spectrum clearly displays a 7.0 mhz signal into the antenna socket of the valve receiver as low as 0.016micro volts(As low as my sig gen will go)

      I am now about to build another ensemble LF as I understand the bandpass filters cover 1.6 and 450khz .

      QUESTION
      My question is : Would it be possible or even beneficial(for example in reducing Inter modulation products etc )for me to modify the bandpass filters to provide a narrower say, 100khz bandwidth at the Intermediate Frequencies of say 1.62 and 5.645Mhz.

      I am not clever enough to design the filters so if anyone could advise or point me in the right direction (or indeed say im wasting my time)! it would be much appreciated.Iknow there is some software called ELSIE..would this help?

      Thanks in advance

      Robert

      MOHFN
    • Alan
      ... Subject: [softrock40] Using rx ensemble II at Intermediate Frequencies. ... Robert, It really depends whether there are signals there to filter out. How
      Message 2 of 2 , Mar 1, 2013
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        ----- Original Message -----
        Subject: [softrock40] Using rx ensemble II at Intermediate Frequencies.


        >
        > I am currently using an rx ensemble (HF) to tap into the IF of various valve receivers including a Drake R4B 5.645Mhz and a
        > homebrew dual conversion at 1.62Mhz (1st IF).Both seem to work very well tapping in before the IF Filters allowing me "see" the
        > whole band by setting the ensemble to 5.6 and 1.6Mhz respectively.Im not sure how to make meaningful snr measurements but the
        > rocky spectrum clearly displays a 7.0 mhz signal into the antenna socket of the valve receiver as low as 0.016micro volts(As low
        > as my sig gen will go)
        >
        > I am now about to build another ensemble LF as I understand the bandpass filters cover 1.6 and 450khz .
        >
        > QUESTION
        > My question is : Would it be possible or even beneficial(for example in reducing Inter modulation products etc )for me to modify
        > the bandpass filters to provide a narrower say, 100khz bandwidth at the Intermediate Frequencies of say 1.62 and 5.645Mhz.
        >

        Robert,

        It really depends whether there are signals there to filter out. How much there is prior to your tap. Many older receivers have
        tuning, IF filters and BPFs.
        And if the Softrock is vulnerable to any frequencies there. Most commonly a problem are odd multiples of the tuned frequency.

        > I am not clever enough to design the filters so if anyone could advise or point me in the right direction (or indeed say im
        > wasting my time)! it would be much appreciated.Iknow there is some software called ELSIE..would this help?

        Yes, Elsie http://tonnesoftware.com/elsie.html (second down in my Google search but Google knows too much about what I search for!)
        is free unless you want advanced features. It will help once you can trust the results you get..

        73 Alan G4ZFQ
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