Loading ...
Sorry, an error occurred while loading the content.

A SoftRock TOP BAND QRO Ensemble for Christmas ? ( Part Two )

Expand Messages
  • Ed
    To continue from Part One: 6) CW TEST : Apply the 13.8 Volts to the Ensemble, Select the TUNE function and monitor the NO DRIVE current value. This should be
    Message 1 of 6 , Nov 21, 2012
    • 0 Attachment
      To continue from Part One:

      6) CW TEST : Apply the 13.8 Volts to the Ensemble, Select the TUNE function and monitor the NO DRIVE current value. This should be approximately 0.17 Amps. Measure the voltage across R48 and R49. I measured 0.027 and 0.029 Volts across the now 0.69 ohm source resistors.

      7) Connect an oscilloscope to a 50 ohm load fitted at the Antenna socket and gradually increase the TX Drive. My unit produced 44 Volts Peak to Peak at the output. The current measured 0.7 Amps and the voltages across R48, R49 now reading 0.207 and 0.214 Volts in this full drive condition. The power output was 4.838 Watts.

      8) TWO TONE TEST : Using the PSDR two tone test app, increase the drive level and monitor the waveform. My unit produced a clean waveform up to 41 Volts Peak to Peak before the start of limiting. The current measured 0.43 Amps at the maximum output of 5.94 Watts PEP.

      9 ) See in GM3SBC PHOTOS section for waveforms etc

      10 ) Under continuous CW maximum power the heatsink is only slightly warm. The two new transistors can be fitted with a flat sheet heatsink held by using a longer main heatsink screw. Thermal paste may be added under the flat side of the BS170.

      11 ) The Ensemble has been in use over the last days and is just a Blast !

      Thanks Tony for the spares !

      73s Ed GM3SBC
    • Alan
      ... Subject: [softrock40] A SoftRock TOP BAND QRO Ensemble for Christmas ? ( Part Two ) ... Ed , In fact the spares are supplied in case matching is required.
      Message 2 of 6 , Nov 21, 2012
      • 0 Attachment
        ----- Original Message -----
        Subject: [softrock40] A SoftRock TOP BAND QRO Ensemble for Christmas ? ( Part Two )


        >
        > Thanks Tony for the spares !
        >

        Ed ,

        In fact the spares are supplied in case matching is required. http://sites.google.com/site/g4zfqradio/matching-bs170-for-softrock

        Your use is interesting.
        Like Warren has said, on lower bands two BS170s will produce over two watts but this should not be attempted without testing on the
        higher frequencies.
        Warren's method looks good for those without scopes.
        I've never tested for maximum power, being content with one watt but I presume the maximum clean power drops as frequency rises.
        Mine, old multiband 6.3 Softrock, is only clean at 0.5 watts on 10m. (12V supply)

        73 Alan G4ZFQ
      • Ed
        Hi Alan, Yes I was aware of the matching saga and spares etc. In reality these devices have wide tolerance in most of the characteristics. It is well nigh
        Message 3 of 6 , Nov 21, 2012
        • 0 Attachment
          Hi Alan,
          Yes I was aware of the matching saga and spares etc. In reality these devices have wide tolerance in most of the characteristics. It is well nigh impossible to not only match the Pinch Off but also the Transconductance. Then even if that was possible what then happens with temperature variations ? So unless builders find themselves being unable to sleep at night for fear of their mismatch, its best to go to the pub and have a beer. There are ways to design all these variations out but it is beyond the scope of this type of application.

          I am glad that Tony only gave me the TWO spares, It was a no brainer on which ones I should fit !

          Regards
          Ed GM3SBC


          --- In softrock40@yahoogroups.com, "Alan" <alan4alan@...> wrote:
          >
          >
          > ----- Original Message -----
          > Subject: [softrock40] A SoftRock TOP BAND QRO Ensemble for Christmas ? ( Part Two )
          >
          >
          > >
          > > Thanks Tony for the spares !
          > >
          >
          > Ed ,
          >
          > In fact the spares are supplied in case matching is required. http://sites.google.com/site/g4zfqradio/matching-bs170-for-softrock
          >
          > Your use is interesting.
          > Like Warren has said, on lower bands two BS170s will produce over two watts but this should not be attempted without testing on the
          > higher frequencies.
          > Warren's method looks good for those without scopes.
          > I've never tested for maximum power, being content with one watt but I presume the maximum clean power drops as frequency rises.
          > Mine, old multiband 6.3 Softrock, is only clean at 0.5 watts on 10m. (12V supply)
          >
          > 73 Alan G4ZFQ
          >
        • Chris Wilson
          ... 21/11/2012 17:57 I have a RXTX V6.2 kit to build, for 160 meters, can I copy this mod onto that board, too? I haven t started the build yet, but have two
          Message 4 of 6 , Nov 21, 2012
          • 0 Attachment
            >
            > Hi Alan,
            > Yes I was aware of the matching saga and spares etc. In reality
            > these devices have wide tolerance in most of the characteristics. It
            > is well nigh impossible to not only match the Pinch Off but also the
            > Transconductance. Then even if that was possible what then happens
            > with temperature variations ? So unless builders find themselves
            > being unable to sleep at night for fear of their mismatch, its best
            > to go to the pub and have a beer. There are ways to design all these
            > variations out but it is beyond the scope of this type of application.

            > I am glad that Tony only gave me the TWO spares, It was a no
            > brainer on which ones I should fit !

            > Regards
            > Ed GM3SBC



            21/11/2012 17:57


            I have a RXTX V6.2 kit to build, for 160 meters, can I copy this mod
            onto that board, too? I haven't started the build yet, but have two
            transistors over from my higher band RXTX Ensemble V6.3 build. I am
            going to order the synthesizer board add on for the V6.2 tonight, then all I
            am short of is the time to build the thing ;)

            Thanks for posting this interesting mod.



            --
            Best Regards,
            Chris Wilson. 2E0ILY
          • Alan
            ... Subject: [softrock40] Re: A SoftRock TOP BAND QRO Ensemble for Christmas ? ( Part Two ) ... Ed, Right, others have expressed this opinion but not so
            Message 5 of 6 , Nov 21, 2012
            • 0 Attachment
              ----- Original Message -----
              Subject: [softrock40] Re: A SoftRock TOP BAND QRO Ensemble for Christmas ? ( Part Two )


              > I was aware of the matching saga and spares etc. In reality these devices have wide tolerance in most of the characteristics. It
              > is well nigh impossible to not only match the Pinch Off but also the Transconductance. Then even if that was possible what then
              > happens with temperature variations ? So unless builders find themselves being unable to sleep at night for fear of their
              > mismatch, its best to go to the pub and have a beer.

              Ed,

              Right, others have expressed this opinion but not so robustly.
              So Robby should relax his recommendation?
              I'm off to the pub.

              73 Alan G4ZFQ
            • Ed
              Hi Alan, Good on you, I m impressed, LoL, yes I am having a very nice English ale at this moment, Sure in the knowledge that I won t even attempt to match
              Message 6 of 6 , Nov 21, 2012
              • 0 Attachment
                Hi Alan,
                Good on you, I'm impressed, LoL, yes I am having a very nice English ale at this moment, Sure in the knowledge that I won't even attempt to match them. I must say though, it really has transformed the performance, Top band is going to be of great interest over this winter period. You noticed that I did not mention any other frequency band. These bands would be work in progress. Each band to be addressed in their own right. But you never know, I might be tempted. At this moment I am improving my 160 metre Antenna. I have had many great contacts since going 'QRO' on CW and SSB. I had a replay of my SSB transmission from the Outer Hebrides and it sounded just fine. I would be most interested in others of 'Braveheart' to report their results.
                To Tony, .... the softrock range has been an inspiration to hams the world over. It is entry level , yes, and that is its greatest strength. Bravo !

                Best Regards to all.

                Ed GM3SBC


                --- In softrock40@yahoogroups.com, "Alan" <alan4alan@...> wrote:
                >
                >
                > ----- Original Message -----
                > Subject: [softrock40] Re: A SoftRock TOP BAND QRO Ensemble for Christmas ? ( Part Two )
                >
                >
                > > I was aware of the matching saga and spares etc. In reality these devices have wide tolerance in most of the characteristics. It
                > > is well nigh impossible to not only match the Pinch Off but also the Transconductance. Then even if that was possible what then
                > > happens with temperature variations ? So unless builders find themselves being unable to sleep at night for fear of their
                > > mismatch, its best to go to the pub and have a beer.
                >
                > Ed,
                >
                > Right, others have expressed this opinion but not so robustly.
                > So Robby should relax his recommendation?
                > I'm off to the pub.
                >
                > 73 Alan G4ZFQ
                >
              Your message has been successfully submitted and would be delivered to recipients shortly.