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Re: [softrock40] Re: Small RF amps for RXTX Ensemble?

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  • AI2Q
    Andy, the G6ALU amplifier, using MOSFETs, works really nicely. Easy to build, too. I etched my own PCB for it, using the image in the docs file. Photo
    Message 1 of 15 , Aug 18, 2012
    Andy, the G6ALU amplifier, using MOSFETs, works really nicely. Easy to build, too.  I etched my own PCB for it, using the image in the docs file.
     
    Photo attached.
     
    I use mine as an IPA to drive my EB-104 MRF-150 amplifier to 600W output from a homebrew G3XJP all-band 160-10M transceiver. I highly recommend the design.
     
     
    Vy 73, AI2Q, Alex
    Member: ARRL, FOC, RSGB, CWops, QRP-L, Antique Wireless Association, New England Radio Discussion Society, DXCC Honor Roll, 16ØM DXCC, 8ØM DXCC
    http://home.roadrunner.com/~alexmm
     
     
     
     
     
    ----- Original Message -----
    From: yl2gqn
    Sent: Saturday, August 18, 2012 7:15 AM
    Subject: [softrock40] Re: Small RF amps for RXTX Ensemble?

     

    Hi,

    I'm use WA2EBY PA with RXTX ensamble. Works great !!!!
    You can found a lot about this PA in google, one from them is http://www.golddredgervideo.com/kc0wox/wa2ebyamp/

    Regards,
    Andy YL2QN

    --- In softrock40@yahoogroups.com, Chris Wilson <chris@...> wrote:
    >
    >
    >
    > 18/08/2012 10:37
    >
    > What RF amplifiers are people trying with the Softrock RXTX Ensemble?
    > Either as a kit, from plans, or as a ready built device? Looking at
    > getting maybe 10 Watts or so. I am building mine for 30, 20 and 17 meter
    > bands. Thanks.
    >
    > --
    > Best Regards,
    > Chris Wilson. M6DFV
    > mailto: chris@...
    >

  • Peter Johnson
    Hi Christos. ... How did you modify the front end of the above amp as its drive requirments are very low for softrock use. Did you remove the the first stage
    Message 2 of 15 , Aug 18, 2012
      Hi Christos.
      On 18/08/2012 14:53, sv1eia wrote:
      >
      > 20W PA
      > -> http://myweb.tiscali.co.uk/radiokits/radio-related/20W_PA/
      >
      How did you modify the front end of the above amp as its drive
      requirments are very low for softrock use.
      Did you remove the the first stage or just increase the attenuation.

      Regards Peter F1VKK
    • sv1eia
      Hi Peter, Almost all of those qrp pa s have low input, so I used a simple attenuator pad. On some early experiments I bypassed the two BS170 of the softrocks
      Message 3 of 15 , Aug 18, 2012
        Hi Peter,

        Almost all of those qrp pa's have low input, so I used a simple attenuator pad.
        On some early experiments I bypassed the two BS170 of the softrocks and get the out from 2N2222 to feed the PAs.

        73,
        Christos SV1EIA


        --- In softrock40@yahoogroups.com, Peter Johnson <m1bcv@...> wrote:
        >
        > Hi Christos.
        > On 18/08/2012 14:53, sv1eia wrote:
        > >
        > > 20W PA
        > > -> http://myweb.tiscali.co.uk/radiokits/radio-related/20W_PA/
        > >
        > How did you modify the front end of the above amp as its drive
        > requirments are very low for softrock use.
        > Did you remove the the first stage or just increase the attenuation.
        >
        > Regards Peter F1VKK
        >
      • sv1eia
        Jerry, You can do it your own way, nobody stops you. Since you have spoken though about throw away RF, its the same as when you remove the first stages of the
        Message 4 of 15 , Aug 18, 2012
          Jerry,

          You can do it your own way, nobody stops you.

          Since you have spoken though about throw away RF, its the same as when you remove the first stages of the PA, exactly the same, you also throw away RF there mate if you remove it.
          You need to see though which stage introduces the largest IMD.. so to rectify it since we talk about PAs.

          73,
          Christos SV1EIA


          --- In softrock40@yahoogroups.com, "Jerry Kaidor" <jerry@...> wrote:
          >
          > > Hi Peter,
          > >
          > > Almost all of those qrp pa's have low input, so I used a simple attenuator
          > > pad.
          >
          > *** How about modifying one of those PAs and building it without the input
          > stage? Seems a shame to throw away RF.
          >
          > - Jerry Kaidor, KF6VB
          >
        • Jerry Kaidor
          ... *** How about modifying one of those PAs and building it without the input stage? Seems a shame to throw away RF. - Jerry Kaidor, KF6VB
          Message 5 of 15 , Aug 18, 2012
            > Hi Peter,
            >
            > Almost all of those qrp pa's have low input, so I used a simple attenuator
            > pad.

            *** How about modifying one of those PAs and building it without the input
            stage? Seems a shame to throw away RF.

            - Jerry Kaidor, KF6VB
          • sv1eia
            ..whatever
            Message 6 of 15 , Aug 18, 2012
              ..whatever


              --- In softrock40@yahoogroups.com, "Jerry Kaidor" <jerry@...> wrote:
              >
              > > Jerry,
              > >
              > > You can do it your own way, nobody stops you.
              > >
              > > Since you have spoken though about throw away RF, its the same as when you
              > > remove the first stages of the PA, exactly the same, you also throw away
              > > RF there mate if you remove it.
              >
              > *** No, you don't throw away RF that way - because you never created it in
              > the first place. As far as removing the stage from the Softrock - that's
              > all tied in with the rcv/xmit switching of the transceiver ( in my case
              > RXTX Ensemble ). If one is building a PA from scratch, it seems simpler
              > to
              > just build the right one.
              >
              > Every amplification stage introduces distortion and noise. All else
              > being equal, it seems a better design practice to get by with less
              > stages, rather than throw away RF ( so you get to use more stages ).
              >
              > - Jerry Kaidor, KF6VB
              >
            • Jerry Kaidor
              ... *** No, you don t throw away RF that way - because you never created it in the first place. As far as removing the stage from the Softrock - that s all
              Message 7 of 15 , Aug 18, 2012
                > Jerry,
                >
                > You can do it your own way, nobody stops you.
                >
                > Since you have spoken though about throw away RF, its the same as when you
                > remove the first stages of the PA, exactly the same, you also throw away
                > RF there mate if you remove it.

                *** No, you don't throw away RF that way - because you never created it in
                the first place. As far as removing the stage from the Softrock - that's
                all tied in with the rcv/xmit switching of the transceiver ( in my case
                RXTX Ensemble ). If one is building a PA from scratch, it seems simpler
                to
                just build the right one.

                Every amplification stage introduces distortion and noise. All else
                being equal, it seems a better design practice to get by with less
                stages, rather than throw away RF ( so you get to use more stages ).

                - Jerry Kaidor, KF6VB
              • MIKE DURKIN
                That link is outdated and redirects to MKARS80 Transceiver kit, Do you have an updated link? If the two BS170 s are bypassed... the drive must be close to what
                Message 8 of 15 , Aug 18, 2012
                  That link is outdated and redirects to MKARS80 Transceiver kit,
                  Do you have an updated link?

                  If the two BS170's are bypassed... the drive must be close to what a UHFSDR is ...?

                  Mike KC7NOA


                  To: softrock40@yahoogroups.com
                  From: sv1eia@...
                  Date: Sat, 18 Aug 2012 16:04:34 +0000
                  Subject: [softrock40] Re: Small RF amps for RXTX Ensemble?

                   
                  Hi Peter,

                  Almost all of those qrp pa's have low input, so I used a simple attenuator pad.
                  On some early experiments I bypassed the two BS170 of the softrocks and get the out from 2N2222 to feed the PAs.

                  73,
                  Christos SV1EIA

                  --- In softrock40@yahoogroups.com, Peter Johnson <m1bcv@...> wrote:
                  >
                  > Hi Christos.
                  > On 18/08/2012 14:53, sv1eia wrote:
                  > >
                  > > 20W PA
                  > > -> http://myweb.tiscali.co.uk/radiokits/radio-related/20W_PA/
                  > >
                  > How did you modify the front end of the above amp as its drive
                  > requirments are very low for softrock use.
                  > Did you remove the the first stage or just increase the attenuation.
                  >
                  > Regards Peter F1VKK
                  >


                • Jim Smith
                  Hi Mike, Try http://www.radio-kits.co.uk/ scroll left hand frame to G6ALU s Private Pages then click on 20W FET PA. I built one for my Pic-A-Star transceiver,
                  Message 9 of 15 , Aug 19, 2012
                    Hi Mike,

                    Try http://www.radio-kits.co.uk/ scroll left hand frame to G6ALU's
                    Private Pages then click on 20W FET PA.

                    I built one for my Pic-A-Star transceiver, works fb.

                    73

                    Jim - G3ZQC

                    MIKE DURKIN wrote:
                    >
                    >
                    > That link is outdated and redirects to MKARS80 Transceiver kit,
                    > Do you have an updated link?
                    >
                    > snip...
                  • Mike Loebl
                    We have a kit currently in beta testing by a few members on the SR list: http://www.hobbypcb.com/amateur-radio/amateur-radio/hardrock-50-hf-power-amp -kit.html
                    Message 10 of 15 , Aug 19, 2012
                      We have a kit currently in beta testing by a few members on the SR list:
                      http://www.hobbypcb.com/amateur-radio/amateur-radio/hardrock-50-hf-power-amp
                      -kit.html
                      and soon in a barebones kit will be offered without case, etc:
                      http://www.hobbypcb.com/amateur-radio/amateur-radio/barebones-hardrock-50-ki
                      t.html

                      160 - 6m, .5 or 5w drive options, 40-50W on 160-10M, 30-35W on 6M, and an
                      open source firmware...
                      http://code.google.com/p/hardrock-50/

                      It's based on Jim Veatch's (WA2EUJ) ARRL Homebrew Challenge winner.

                      -Mike
                      KB1MTS

                      -----Original Message-----
                      From: softrock40@yahoogroups.com [mailto:softrock40@yahoogroups.com] On
                      Behalf Of Chris Wilson
                      Sent: Saturday, August 18, 2012 5:41 AM
                      To: softrock40@yahoogroups.com
                      Subject: [softrock40] Small RF amps for RXTX Ensemble?



                      18/08/2012 10:37

                      What RF amplifiers are people trying with the Softrock RXTX Ensemble?
                      Either as a kit, from plans, or as a ready built device? Looking at getting
                      maybe 10 Watts or so. I am building mine for 30, 20 and 17 meter bands.
                      Thanks.

                      --
                      Best Regards,
                      Chris Wilson. M6DFV
                      mailto: chris@...



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