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Re: [softrock40] Image rejection

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  • tom
    Alan, what do you mean by not using the monitor/mixer? Tom ... From: Alan To: softrock40@yahoogroups.com Sent: Monday, March 01, 2010 7:20 AM Subject: Re:
    Message 1 of 18 , Mar 1, 2010
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      Alan,
       
      what do you mean by not using the monitor/mixer?
       
      Tom
       
       
      ----- Original Message -----
      From: Alan
      Sent: Monday, March 01, 2010 7:20 AM
      Subject: Re: [softrock40] Image rejection

       


      ----- Original Message -----
      From: "wa1vta01452"
      Subject: [softrock40] Image rejection

      What particular card should not make any difference. But do NOT use the
      "Monitor/Mixer" of the D44.
      I do have D44s and on RX I get something like -30db BEFORE any software
      correction, then -50dB is easily achieved with any manual software
      adjustments. Often much more.

      Similarly on TX, about 30dB due to hardware, much better after adjusting.

      All audio cables should be shielded, make sure connections are good, 1/8
      jacks can be suspect.
      Ground loops will not affect image rejection, just create a lot of "hash"
      spreading from the centre.

      73 Alan G4ZFQ

    • Alan
      ... From: tom Subject: Re: [softrock40] Image rejection ... I m still using the old control panel so can t describe the new. The mixer controls should not
      Message 2 of 18 , Mar 1, 2010
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        ----- Original Message -----
        From: "tom"
        Subject: Re: [softrock40] Image rejection



        >what do you mean by not using the monitor/mixer?

        I'm still using the old control panel so can't describe the new.
        The mixer controls should not work. If they do you may not get any TX image
        rejection.
        If they do there is a way to disable them, a drop-down or box..

        73 Alan G4ZFQ
      • Ben Hall
        Good evening all, In the mail today arrived the final components to complete my electronically switched BPF for the my Lite+USB XTtall V9.0 receiver. While I
        Message 3 of 18 , Mar 1, 2010
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          Good evening all,

          In the mail today arrived the final components to complete my
          electronically switched BPF for the my Lite+USB XTtall V9.0 receiver.

          While I have no problems winding toroid inductors - meaning that I
          possess normal vision (albeit with fairly thick glasses) and normal
          manually dexterity (ok, I have moments of shakiness), I started
          wondering if anyone had substituted SMD inductors for the toroid
          inductors on the BPF.

          Dave WB6DHW uses SMD inductors on his successful WB6DHW
          Band Pass Filter Board. I've built one and it seems to work just fine.
          So I know that SMD inductors can be successfully used in RF bandpass
          filters.

          (Side Note: I seem to recall a section in the builders notes that state
          that toroids may have lower loss than the SMD parts. The AADE filter
          design software confirms this when I enter Q's of 25 from the data
          sheets of the WB6DHW design parts into the SoftRock bandpass
          configuration compared to an assumed infinite Q for a toroid.)

          So here's my crazy idea - has anyone built up an electrically switched
          SoftRock BPF substituting SMD inductors for the the wound toroids?

          I may just give this a whirl!

          thanks much,
          ben
          --
          Ben Hall, kd5byb@... - ALWAYS OUTNUMBERED, NEVER OUTGUNNED.
        • Jack Smith
          In addition to the Q loss (typical SMD RF choke type inductor in the 25-50 range, powdered iron cores in the 150-300 range depending on size and other
          Message 4 of 18 , Mar 1, 2010
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            In addition to the Q loss (typical SMD RF choke type inductor in the 25-50 range, powdered iron cores in the 150-300 range depending on size and other factors), many of SMD parts are wound on ferrite cores. If you are concerned with wringing the best intermodulation performance from a filter, it's best to avoid ferrite core inductors. Even powdered iron can be problems at some levels of performance, but powdered iron is clearly to be preferred over ferrite core parts.

            Jack K8ZOA


            On 3/1/2010 6:28 PM, Ben Hall wrote:
             

            Good evening all,

            In the mail today arrived the final components to complete my
            electronically switched BPF for the my Lite+USB XTtall V9.0 receiver.

            While I have no problems winding toroid inductors - meaning that I
            possess normal vision (albeit with fairly thick glasses) and normal
            manually dexterity (ok, I have moments of shakiness), I started
            wondering if anyone had substituted SMD inductors for the toroid
            inductors on the BPF.

            Dave WB6DHW uses SMD inductors on his successful WB6DHW
            Band Pass Filter Board. I've built one and it seems to work just fine.
            So I know that SMD inductors can be successfully used in RF bandpass
            filters.

            (Side Note: I seem to recall a section in the builders notes that state
            that toroids may have lower loss than the SMD parts. The AADE filter
            design software confirms this when I enter Q's of 25 from the data
            sheets of the WB6DHW design parts into the SoftRock bandpass
            configuration compared to an assumed infinite Q for a toroid.)

            So here's my crazy idea - has anyone built up an electrically switched
            SoftRock BPF substituting SMD inductors for the the wound toroids?

            I may just give this a whirl!

            thanks much,
            ben
            --
            Ben Hall, kd5byb@gmail. com - ALWAYS OUTNUMBERED, NEVER OUTGUNNED.

          • jorschei
            Hi Ben, SMD coils are usefull even when the Q factor is lower than Amidon torriods. For SDR we need no narrow passbands. I use COILCRAFT surface mount
            Message 5 of 18 , Mar 2, 2010
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              Hi Ben,

              SMD coils are usefull even when the Q factor is lower than Amidon torriods. For SDR we need no narrow passbands. I use COILCRAFT surface mount inductors High Q series 1812CS (4532) for the KTH-SDR wideband modulair receiver and it work well.See the KIT doc on Rob his site.
              http://home.kpn.nl/rw.engberts/sdr_kth_buyers.htm
              The have ceramic forms and no ferrite. Filter with 1.5 dB loss can be accepted.

              73' Joris PE1KTH



              > So I know that SMD inductors can be successfully used in RF

              --- In softrock40@yahoogroups.com, Ben Hall <kd5byb@...> wrote:
              >
              > Good evening all,
              >
              > In the mail today arrived the final components to complete my
              > electronically switched BPF for the my Lite+USB XTtall V9.0 receiver.
              >
              > While I have no problems winding toroid inductors - meaning that I
              > possess normal vision (albeit with fairly thick glasses) and normal
              > manually dexterity (ok, I have moments of shakiness), I started
              > wondering if anyone had substituted SMD inductors for the toroid
              > inductors on the BPF.
              >
              > Dave WB6DHW uses SMD inductors on his successful WB6DHW
              > Band Pass Filter Board. I've built one and it seems to work just fine.


              bandpass
              > filters.
              >
              > (Side Note: I seem to recall a section in the builders notes that state
              > that toroids may have lower loss than the SMD parts. The AADE filter
              > design software confirms this when I enter Q's of 25 from the data
              > sheets of the WB6DHW design parts into the SoftRock bandpass
              > configuration compared to an assumed infinite Q for a toroid.)
              >
              > So here's my crazy idea - has anyone built up an electrically switched
              > SoftRock BPF substituting SMD inductors for the the wound toroids?
              >
              > I may just give this a whirl!
              >
              > thanks much,
              > ben
              > --
              > Ben Hall, kd5byb@... - ALWAYS OUTNUMBERED, NEVER OUTGUNNED.
              >
            • netnovel2005
              Hello, I use chip inductor as BPF. There is few problem. 3 pole BPF has not enough rejection of 2 times of frequency. I add stop band filter to BPF of 80m
              Message 6 of 18 , Mar 2, 2010
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                Hello,

                I use chip inductor as BPF.

                There is few problem. 3 pole BPF has not enough rejection of 2 times of frequency. I add stop band filter to BPF of 80m against 40m.

                Please look my schematics.

                http://zao.jp/radio/GPS/schematics.jpg

                C51, L26 is stop band filter.

                This stop band filter is not complete. I design 5 pole BPF for next version now.

                73
                Miura
                JA7TDO
              • w0fms
                I m building the filter board myself right now... whereas the main board was fun to build, the filter board is a PITA.... I d take a lower Q 5 pole filter any
                Message 7 of 18 , Mar 3, 2010
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                  I'm building the filter board myself right now... whereas the main board was fun to build, the filter board is a PITA....

                  I'd take a lower Q 5 pole filter any day over 71 turns x2 plus 50 turns on a core form that's really not big enough for 71 turns anyway. And do I have 69 turns on one and 72 on the other? Maybe... From now on (the last three sections) I'm bringing the wound inductors into work and measuring them on a LCR bridge to make sure we are right. Really otherwise you are guessing. Repeat that 15 times and you have the board.

                  I do understand that going with good quality Coilcraft-type chip inductors would make the kit a little more expensive... more so if the fiter goes up to 5 poles on each band.. but reproducibility and quality of the product from both a mechanical and electrical standpoint goes up as well. I'd hate to try to run a vibe test on that filter board the way it is.

                  I hate winding toroids.. and really, to build this correctly one needs to be too careful or have a LCR bridge of some sort. Going to prewound transformers and inductors would help the more neophyte builders which I believe is one of the goals of the Softrocks, is it not?

                  The V9.0 receiver board converted to all SMT with the filters built in for HF and a plug in or two for VHF (Bigger AVR w/xtal and two more mux ic's.. 8 bands) would be an almost ideal project, IMHO. Yes I said SMT.. it's easier once you get used to it. Especially when the original design is a hybrid leaded/SMT design anyway. I also hate those leaded dipped ceramic caps.. they are way too easy to break.

                  I'm not faulting Tony (or Jan or anyone else) for the current design.. it makes perfectly good sense based on the evolution of the design. But switching over to all commercial components would almost make a SDR receiver for the masses out of the current design. Yup it might go up to $90 for the kit.. it'd be worth it. My time winding those cores are worth the $30 difference.

                  At least a new filter board would be a good idea.

                  Fred W0FMS

                  --- In softrock40@yahoogroups.com, "netnovel2005" <ja7tdo@...> wrote:
                  >
                  >
                  >
                  > Hello,
                  >
                  > I use chip inductor as BPF.
                  >
                  > There is few problem. 3 pole BPF has not enough rejection of 2 times of frequency. I add stop band filter to BPF of 80m against 40m.
                  >
                  > Please look my schematics.
                  >
                  > http://zao.jp/radio/GPS/schematics.jpg
                  >
                  > C51, L26 is stop band filter.
                  >
                  > This stop band filter is not complete. I design 5 pole BPF for next version now.
                  >
                  > 73
                  > Miura
                  > JA7TDO
                  >
                • Peter
                  I m using five 3rd-order filters, electronically switched, with SMT inductors, and it works fine. Also, Pulse Engineering makes a transformer which works as
                  Message 8 of 18 , Mar 3, 2010
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                    I'm using five 3rd-order filters, electronically switched, with SMT inductors, and it works fine. Also, Pulse Engineering makes a transformer which works as well as a hand-wound toroid. It's available from mouser in single quantity for less than $3.00.

                    --- In softrock40@yahoogroups.com, "w0fms" <fred@...> wrote:
                    >
                    >
                    >
                    >
                    >
                    >
                    > I'm building the filter board myself right now... whereas the main board was fun to build, the filter board is a PITA....
                    >
                    > I'd take a lower Q 5 pole filter any day over 71 turns x2 plus 50 turns on a core form that's really not big enough for 71 turns anyway. And do I have 69 turns on one and 72 on the other? Maybe... From now on (the last three sections) I'm bringing the wound inductors into work and measuring them on a LCR bridge to make sure we are right. Really otherwise you are guessing. Repeat that 15 times and you have the board.
                    >
                    > I do understand that going with good quality Coilcraft-type chip inductors would make the kit a little more expensive... more so if the fiter goes up to 5 poles on each band.. but reproducibility and quality of the product from both a mechanical and electrical standpoint goes up as well. I'd hate to try to run a vibe test on that filter board the way it is.
                    >
                    > I hate winding toroids.. and really, to build this correctly one needs to be too careful or have a LCR bridge of some sort. Going to prewound transformers and inductors would help the more neophyte builders which I believe is one of the goals of the Softrocks, is it not?
                    >
                    > The V9.0 receiver board converted to all SMT with the filters built in for HF and a plug in or two for VHF (Bigger AVR w/xtal and two more mux ic's.. 8 bands) would be an almost ideal project, IMHO. Yes I said SMT.. it's easier once you get used to it. Especially when the original design is a hybrid leaded/SMT design anyway. I also hate those leaded dipped ceramic caps.. they are way too easy to break.
                    >
                    > I'm not faulting Tony (or Jan or anyone else) for the current design.. it makes perfectly good sense based on the evolution of the design. But switching over to all commercial components would almost make a SDR receiver for the masses out of the current design. Yup it might go up to $90 for the kit.. it'd be worth it. My time winding those cores are worth the $30 difference.
                    >
                    > At least a new filter board would be a good idea.
                    >
                    > Fred W0FMS
                    >
                    > --- In softrock40@yahoogroups.com, "netnovel2005" <ja7tdo@> wrote:
                    > >
                    > >
                    > >
                    > > Hello,
                    > >
                    > > I use chip inductor as BPF.
                    > >
                    > > There is few problem. 3 pole BPF has not enough rejection of 2 times of frequency. I add stop band filter to BPF of 80m against 40m.
                    > >
                    > > Please look my schematics.
                    > >
                    > > http://zao.jp/radio/GPS/schematics.jpg
                    > >
                    > > C51, L26 is stop band filter.
                    > >
                    > > This stop band filter is not complete. I design 5 pole BPF for next version now.
                    > >
                    > > 73
                    > > Miura
                    > > JA7TDO
                    > >
                    >
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