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Ensemble RX II deaf from 4-8 MHz

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  • jmshaffer_pa
    I have a Softrock that I bought second-hand from another user last year. It seems to hardly receive anything from 4 to 8 MHz, the bandpass filter #1 range.
    Message 1 of 2 , Feb 23, 2013
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      I have a Softrock that I bought second-hand from another user last year. It seems to hardly receive anything from 4 to 8 MHz, the bandpass filter #1 range. I'll get a few strong broadcast stations (unless they're images... I haven't taken time to verify the frequencies on all of them) but hardly ever any hams or utilities. In fact, in some parts of the range, the signal display is virtually flat. All other bands work fine. And, if I manually set the bandpass filter selection from #1 to #2 (nominally 8-16 MHz), I get great, although sometimes image-plagued, reception from 4-8 also.

      I see comments here on the list about deafness being caused by failure to clean the enamel from the coil wire before soldering it in, so I pulled up the assembly instructions and schematics and tested for continuity through the filter #1 inductors. They're fine. I don't know what else to try, because I don't have a scope or a signal generator.

      So, is the 4-8 MHz filter just a particularly bad filter (which I can hardly believe would've been intentional, given the amount of activity on the 40m ham band), or do I have something else going on?
    • EB4APL
      I have seen your problem in the Softrock of a friend, it didn t select the BPF for that band, either automatically or manually. The problem was a bad
      Message 2 of 2 , Feb 23, 2013
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        I have seen your problem in the Softrock of a friend, it didn't select
        the BPF for that band, either automatically or manually. The problem
        was a bad optoisolator, it originally was ok but it became bad later, I
        don't know why. So your problem is either the filter itself, but you say
        that you tested the coils for continuity, or the optoisolator (very rare
        that this kind of failure repeats) or one of the switches . Without a
        scope you can check the output of the optos with a voltmeter while
        exercising the filters in manual. If ok then you can probe the
        corresponding pins in the switches. If the line that connects the opto
        to the switch chips is always low maybe it is connected to ground by a
        solder bridge, check with an ohmmeter with the power off. You can also
        monitor the DC levels of the working filters, both on and off, this can
        give us a clue.

        73 de Ignacio, EB4APL


        On 24/02/2013 1:11, jmshaffer_pa wrote:

        > I have a Softrock that I bought second-hand from another user last year.
        > It seems to hardly receive anything from 4 to 8 MHz, the bandpass filter
        > #1 range. I'll get a few strong broadcast stations (unless they're
        > images... I haven't taken time to verify the frequencies on all of them)
        > but hardly ever any hams or utilities. In fact, in some parts of the
        > range, the signal display is virtually flat. All other bands work fine.
        > And, if I manually set the bandpass filter selection from #1 to #2
        > (nominally 8-16 MHz), I get great, although sometimes image-plagued,
        > reception from 4-8 also.
        >
        > I see comments here on the list about deafness being caused by failure
        > to clean the enamel from the coil wire before soldering it in, so I
        > pulled up the assembly instructions and schematics and tested for
        > continuity through the filter #1 inductors. They're fine. I don't know
        > what else to try, because I don't have a scope or a signal generator.
        >
        > So, is the 4-8 MHz filter just a particularly bad filter (which I can
        > hardly believe would've been intentional, given the amount of activity
        > on the 40m ham band), or do I have something else going on?
        >
        >
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