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10W Linear amp from Kits & Parts. Anyone tried it with SR yet?

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  • drmail377
    At: http://kitsandparts.com/linearamp.php There s a 10W HF linear (CW/SSB) amplifier kit that looks like it will drive with +1dBm. A 5W kit is coming out in
    Message 1 of 22 , Dec 29, 2008
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      At:

      http://kitsandparts.com/linearamp.php

      There's a 10W HF linear (CW/SSB) amplifier kit that looks like it will
      drive with +1dBm. A 5W kit is coming out in January 2009. There are
      LPF and BPF kits available on the site as well.

      Has anyone tried one of these with a Softrock radio yet?

      73's David
    • k5nwa
      ... I have used his bandpass filters for years, but they are rather tight, he has newer versions now that cover a bit more frequency. Unfortunately he doesn t
      Message 2 of 22 , Dec 29, 2008
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        On 12/29/2008 8:23 AM, drmail377 wrote:
        > At:
        >
        > http://kitsandparts.com/linearamp.php
        >
        > There's a 10W HF linear (CW/SSB) amplifier kit that looks like it will
        > drive with +1dBm. A 5W kit is coming out in January 2009. There are
        > LPF and BPF kits available on the site as well.
        >
        > Has anyone tried one of these with a Softrock radio yet?
        >
        > 73's David
        >
        I have used his bandpass filters for years, but they are rather tight,
        he has newer versions now that cover a bit more frequency.

        Unfortunately he doesn't carry it any more but he use to have a 10 band
        filter board which what I have used. I also have his 10 watt linear but
        I have not put it together yet. In a discussion with him the driver
        stage should not be installed, but the SoftRock should drive the finals
        directly otherwise you will overdrive the linear.

        --
        Cecil
        K5NWA
        www.softrockradio.org www.qrpradio.com
        < http://parts.softrockradio.org/>


        "Blessed are the cracked, for they shall let in the light."
      • Christos Nikolaou
        Hi Dave, I have 5 LPF filters from kitsandparts - http://kitsandparts.com/univlpfilter.php each for 160m/80m/40m/20m/10m and working wonderfully with a
        Message 3 of 22 , Dec 29, 2008
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          Hi Dave,

          I have 5 LPF filters from kitsandparts
          ->http://kitsandparts.com/univlpfilter.php
          each for 160m/80m/40m/20m/10m and working wonderfully with a
          4028/ULN2803/relays control (I've pushed them up to 100W).

          For PA I've got the QRP-Linear-PA (1,8 - 150 MHz) (PLB-15) from
          www.box73.de with exceptional gain and IMDs.

          73,
          Christos SV1EIA



          --- In softrock40@yahoogroups.com, "drmail377" <drmail377@...> wrote:
          >
          > At:
          >
          > http://kitsandparts.com/linearamp.php
          >
          > There's a 10W HF linear (CW/SSB) amplifier kit that looks like it will
          > drive with +1dBm. A 5W kit is coming out in January 2009. There are
          > LPF and BPF kits available on the site as well.
          >
          > Has anyone tried one of these with a Softrock radio yet?
          >
          > 73's David
          >
        • Ray
          ,There are two stages of driver - should both be eliminated or just the first (pre-driver)amplifier?? 73, Ray, N0FY SKCC 3704 FH 997 As senseless as the
          Message 4 of 22 , Dec 29, 2008
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            ,There are two stages of driver - should both be eliminated or just the
            first (pre-driver)amplifier??

            73, Ray, N0FY SKCC 3704 FH 997

            As senseless as the world may seem to you, never forget that you contribute
            a fair share to this senselessness by what you do as well as by what you
            don't do.
            Arthur Schnitzler (1867 - 1931)




            > -----Original Message-----
            > From: softrock40@yahoogroups.com
            > [mailto:softrock40@yahoogroups.com] On Behalf Of k5nwa
            > Sent: Monday, December 29, 2008 8:44 AM
            > To: softrock40@yahoogroups.com
            > Subject: Re: [softrock40] 10W Linear amp from Kits & Parts.
            > Anyone tried it with SR yet?
            >
            > On 12/29/2008 8:23 AM, drmail377 wrote:
            > > At:
            > >
            > > http://kitsandparts.com/linearamp.php
            > >
            > > There's a 10W HF linear (CW/SSB) amplifier kit that looks
            > like it will
            > > drive with +1dBm. A 5W kit is coming out in January 2009. There are
            > > LPF and BPF kits available on the site as well.
            > >
            > > Has anyone tried one of these with a Softrock radio yet?
            > >
            > > 73's David
            > >
            > I have used his bandpass filters for years, but they are
            > rather tight, he has newer versions now that cover a bit more
            > frequency.
            >
            > Unfortunately he doesn't carry it any more but he use to have
            > a 10 band filter board which what I have used. I also have
            > his 10 watt linear but I have not put it together yet. In a
            > discussion with him the driver stage should not be installed,
            > but the SoftRock should drive the finals directly otherwise
            > you will overdrive the linear.
            >
            > --
            > Cecil
            > K5NWA
            > www.softrockradio.org www.qrpradio.com
            > < http://parts.softrockradio.org/>
            >
            >
            > "Blessed are the cracked, for they shall let in the light."
            >
            >
            > ------------------------------------
            >
            > Yahoo! Groups Links
            >
            >
            >
          • k5nwa
            ... I was told to eliminate both, the SoftRock has about 1 Watt of power which will overdrive the drivers. -- Cecil K5NWA www.softrockradio.org
            Message 5 of 22 , Dec 29, 2008
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              On 12/29/2008 12:40 PM, Ray wrote:
              > ,There are two stages of driver - should both be eliminated or just the
              > first (pre-driver)amplifier??
              >
              > 73, Ray, N0FY SKCC 3704 FH 997
              >
              > As senseless as the world may seem to you, never forget that you contribute
              > a fair share to this senselessness by what you do as well as by what you
              > don't do.
              > Arthur Schnitzler (1867 - 1931)
              >
              >
              >
              >
              >
              >> -----Original Message-----
              >> From: softrock40@yahoogroups.com
              >> [mailto:softrock40@yahoogroups.com] On Behalf Of k5nwa
              >> Sent: Monday, December 29, 2008 8:44 AM
              >> To: softrock40@yahoogroups.com
              >> Subject: Re: [softrock40] 10W Linear amp from Kits& Parts.
              >> Anyone tried it with SR yet?
              >>
              >> On 12/29/2008 8:23 AM, drmail377 wrote:
              >>
              >>> At:
              >>>
              >>> http://kitsandparts.com/linearamp.php
              >>>
              >>> There's a 10W HF linear (CW/SSB) amplifier kit that looks
              >>>
              >> like it will
              >>
              >>> drive with +1dBm. A 5W kit is coming out in January 2009. There are
              >>> LPF and BPF kits available on the site as well.
              >>>
              >>> Has anyone tried one of these with a Softrock radio yet?
              >>>
              >>> 73's David
              >>>
              >>>
              >> I have used his bandpass filters for years, but they are
              >> rather tight, he has newer versions now that cover a bit more
              >> frequency.
              >>
              >> Unfortunately he doesn't carry it any more but he use to have
              >> a 10 band filter board which what I have used. I also have
              >> his 10 watt linear but I have not put it together yet. In a
              >> discussion with him the driver stage should not be installed,
              >> but the SoftRock should drive the finals directly otherwise
              >> you will overdrive the linear.
              >>
              >> --
              >> Cecil
              >> K5NWA
              >> www.softrockradio.org www.qrpradio.com
              >> < http://parts.softrockradio.org/>
              >>
              >>
              >> "Blessed are the cracked, for they shall let in the light."
              >>
              I was told to eliminate both, the SoftRock has about 1 Watt of power
              which will overdrive the drivers.


              --
              Cecil
              K5NWA
              www.softrockradio.org www.qrpradio.com
              < http://parts.softrockradio.org/>


              "Blessed are the cracked, for they shall let in the light."
            • drmail377
              If the amp is 10W out with 40dB gain as specified the input required is 0dBm. If the Softrock is 1W out which is 30dBm, then a fixed 30dB attenuator between
              Message 6 of 22 , Dec 30, 2008
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                If the amp is 10W out with 40dB gain as specified the input required
                is 0dBm. If the Softrock is 1W out which is 30dBm, then a fixed 30dB
                attenuator between the Softrock and the complete 10W amplifier should
                bring the levels in-line.

                I notice on the amplifier schematic that the transmit input is labeled
                as "to BPF" and the output is labeled to LPF. This seems like a
                non-optimal tx/rx switching arrangement to me; having both filter
                banks in-line during receive. Hmmm...

                David

                --- In softrock40@yahoogroups.com, "Christos Nikolaou" <sv1eia@...> wrote:
                >
                > Hi Dave,
                >
                > I have 5 LPF filters from kitsandparts
                > ->http://kitsandparts.com/univlpfilter.php
                > each for 160m/80m/40m/20m/10m and working wonderfully with a
                > 4028/ULN2803/relays control (I've pushed them up to 100W).
                >
                > For PA I've got the QRP-Linear-PA (1,8 - 150 MHz) (PLB-15) from
                > www.box73.de with exceptional gain and IMDs.
                >
                > 73,
                > Christos SV1EIA
                >
                >
                >
                > --- In softrock40@yahoogroups.com, "drmail377" <drmail377@> wrote:
                > >
                > > At:
                > >
                > > http://kitsandparts.com/linearamp.php
                > >
                > > There's a 10W HF linear (CW/SSB) amplifier kit that looks like it will
                > > drive with +1dBm. A 5W kit is coming out in January 2009. There are
                > > LPF and BPF kits available on the site as well.
                > >
                > > Has anyone tried one of these with a Softrock radio yet?
                > >
                > > 73's David
                > >
                >
              • Christos Nikolaou
                ... I ve measured the IMD from softrock PA and it is not even near the IMD performance of the driver stage from the PLB-15 (KT610: -50dBc) so I do not use the
                Message 7 of 22 , Dec 30, 2008
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                  --- In softrock40@yahoogroups.com, "drmail377" <drmail377@...> wrote:
                  >
                  > If the amp is 10W out with 40dB gain as specified the input required
                  > is 0dBm. If the Softrock is 1W out which is 30dBm, then a fixed 30dB
                  > attenuator between the Softrock and the complete 10W amplifier should
                  > bring the levels in-line.

                  I've measured the IMD from softrock PA and it is not even near the IMD
                  performance of the driver stage from the PLB-15 (KT610: -50dBc) so I
                  do not use the SR PA any more, I take direct output from the QSE and
                  everything is fine.
                  If you put attenuators, then you will just enhance the bad IMD
                  performance of the SR PA.

                  >
                  > I notice on the amplifier schematic that the transmit input is labeled
                  > as "to BPF" and the output is labeled to LPF. This seems like a
                  > non-optimal tx/rx switching arrangement to me; having both filter
                  > banks in-line during receive. Hmmm...


                  Probably we are not on the same page here, the PA I mention is
                  ->http://www.box73.de/catalog/pdf/PLB-15.pdf
                  and it is not saying that.
                • Simon.Bosworth
                  Is this http://www.box73.de/catalog/pdf/PLB-15.pdf available outside Germany? My German is non-existent so I was not able to decipher the shipping/payment
                  Message 8 of 22 , Dec 30, 2008
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                    Is this http://www.box73.de/catalog/pdf/PLB-15.pdf  available outside Germany? My German is non-existent so I was not able to decipher the shipping/payment policies.

                     

                    Cheers,

                    Simon  N0EPW

                     

                    From: softrock40@yahoogroups.com [mailto:softrock40@yahoogroups.com] On Behalf Of Christos Nikolaou
                    Sent: Tuesday, December 30, 2008 9:57 AM
                    To: softrock40@yahoogroups.com
                    Subject: [softrock40] Re: 10W Linear amp from Kits & Parts. Anyone tried it with SR yet?

                     

                    --- In softrock40@yahoogroups.com, "drmail377" <drmail377@...> wrote:

                    >
                    > If the amp is 10W out with 40dB gain as specified the input required
                    > is 0dBm. If the Softrock is 1W out which is 30dBm, then a fixed 30dB
                    > attenuator between the Softrock and the complete 10W amplifier should
                    > bring the levels in-line.

                    I've measured the IMD from softrock PA and it is not even near the IMD
                    performance of the driver stage from the PLB-15 (KT610: -50dBc) so I
                    do not use the SR PA any more, I take direct output from the QSE and
                    everything is fine.
                    If you put attenuators, then you will just enhance the bad IMD
                    performance of the SR PA.

                    >
                    > I notice on the amplifier schematic that the transmit input is labeled
                    > as "to BPF" and the output is labeled to LPF. This seems like a
                    > non-optimal tx/rx switching arrangement to me; having both filter
                    > banks in-line during receive. Hmmm...

                    Probably we are not on the same page here, the PA I mention is
                    ->http://www.box73.de/catalog/pdf/PLB-15.pdf
                    and it is not saying that.

                  • Christos Nikolaou
                    Simon, My german are the same as yours... the schematic though is a bit universal :-) Just send them an email regarding your inquiry (shop@funkamateur.de). I
                    Message 9 of 22 , Dec 30, 2008
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                      Simon,

                      My german are the same as yours... the schematic though is a bit
                      universal :-)
                      Just send them an email regarding your inquiry (shop@...).
                      I also had some questions and they reply in english.
                      At least for Athens/Greece (EU) they send it via registered postage
                      allright.

                      73,
                      Christos SV1EIA


                      --- In softrock40@yahoogroups.com, Simon.Bosworth <simon.bosworth@...>
                      wrote:
                      >
                      > Is this http://www.box73.de/catalog/pdf/PLB-15.pdf available
                      outside Germany? My German is non-existent so I was not able to
                      decipher the shipping/payment policies.
                      >
                      > Cheers,
                      > Simon N0EPW
                      >
                      >
                      > From: softrock40@yahoogroups.com [mailto:softrock40@yahoogroups.com]
                      On Behalf Of Christos Nikolaou
                      > Sent: Tuesday, December 30, 2008 9:57 AM
                      > To: softrock40@yahoogroups.com
                      > Subject: [softrock40] Re: 10W Linear amp from Kits & Parts. Anyone
                      tried it with SR yet?
                      >
                      >
                      > --- In
                      softrock40@yahoogroups.com<mailto:softrock40%40yahoogroups.com>,
                      "drmail377" <drmail377@> wrote:
                      > >
                      > > If the amp is 10W out with 40dB gain as specified the input required
                      > > is 0dBm. If the Softrock is 1W out which is 30dBm, then a fixed 30dB
                      > > attenuator between the Softrock and the complete 10W amplifier should
                      > > bring the levels in-line.
                      >
                      > I've measured the IMD from softrock PA and it is not even near the IMD
                      > performance of the driver stage from the PLB-15 (KT610: -50dBc) so I
                      > do not use the SR PA any more, I take direct output from the QSE and
                      > everything is fine.
                      > If you put attenuators, then you will just enhance the bad IMD
                      > performance of the SR PA.
                      >
                      > >
                      > > I notice on the amplifier schematic that the transmit input is labeled
                      > > as "to BPF" and the output is labeled to LPF. This seems like a
                      > > non-optimal tx/rx switching arrangement to me; having both filter
                      > > banks in-line during receive. Hmmm...
                      >
                      > Probably we are not on the same page here, the PA I mention is
                      > ->http://www.box73.de/catalog/pdf/PLB-15.pdf
                      > and it is not saying that.
                      >
                    • tj_alberta
                      I wonder if the bad IMD from the SR PA Christos is reporting is a general finding? I have not encountered any problems (bad IMD reports on hundreds of PSK31
                      Message 10 of 22 , Dec 30, 2008
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                        I wonder if the bad IMD from the SR PA Christos is reporting is a
                        general finding? I have not encountered any problems (bad IMD reports
                        on hundreds of PSK31 and SSB QSOs) using the SR V 6.2 PA @ 1 W to feed
                        an amplifier. Only if the supply voltage falls much below 12V do I
                        find problems with the transmitted signal.

                        Earl 4Z4TJ

                        --- In softrock40@yahoogroups.com, "Christos Nikolaou" <sv1eia@...> wrote:
                        >
                        > --- In softrock40@yahoogroups.com, "drmail377" <drmail377@> wrote:
                        > >
                        > > If the amp is 10W out with 40dB gain as specified the input required
                        > > is 0dBm. If the Softrock is 1W out which is 30dBm, then a fixed 30dB
                        > > attenuator between the Softrock and the complete 10W amplifier should
                        > > bring the levels in-line.
                        >
                        > I've measured the IMD from softrock PA and it is not even near the IMD
                        > performance of the driver stage from the PLB-15 (KT610: -50dBc) so I
                        > do not use the SR PA any more, I take direct output from the QSE and
                        > everything is fine.
                        > If you put attenuators, then you will just enhance the bad IMD
                        > performance of the SR PA.
                        >
                        > >
                        > > I notice on the amplifier schematic that the transmit input is labeled
                        > > as "to BPF" and the output is labeled to LPF. This seems like a
                        > > non-optimal tx/rx switching arrangement to me; having both filter
                        > > banks in-line during receive. Hmmm...
                        >
                        >
                        > Probably we are not on the same page here, the PA I mention is
                        > ->http://www.box73.de/catalog/pdf/PLB-15.pdf
                        > and it is not saying that.
                        >
                      • Christos Nikolaou
                        Earl, If you see in the files section there is a measured ~28dBc IMD from the SR PA. Compare that to the measurements on the PLB-15 document (-48dBc to
                        Message 11 of 22 , Dec 30, 2008
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                          Earl,

                          If you see in the files section there is a measured ~28dBc IMD from
                          the SR PA. Compare that to the measurements on the PLB-15 document
                          (-48dBc to -66dBc)and I hope that you understand what I am talking about.
                          In my case, I could not reach even the acclaimed -28dBc of the SR PA,
                          I had more like -20dBc but that might be due to local problems.
                          Either way the difference (-28dBc to -48dBc) is quite large, so I
                          decided to scrap the SR PA and stay with the KT610/RD16HHF1 combo
                          where the IMD to Watts ratio is something that (IMHO) I find much better.

                          73,
                          Christos SV1EIA



                          --- In softrock40@yahoogroups.com, "tj_alberta" <earl.rubin@...> wrote:
                          >
                          > I wonder if the bad IMD from the SR PA Christos is reporting is a
                          > general finding? I have not encountered any problems (bad IMD reports
                          > on hundreds of PSK31 and SSB QSOs) using the SR V 6.2 PA @ 1 W to feed
                          > an amplifier. Only if the supply voltage falls much below 12V do I
                          > find problems with the transmitted signal.
                          >
                          > Earl 4Z4TJ
                          >
                          > --- In softrock40@yahoogroups.com, "Christos Nikolaou" <sv1eia@> wrote:
                          > >
                          > > --- In softrock40@yahoogroups.com, "drmail377" <drmail377@> wrote:
                          > > >
                          > > > If the amp is 10W out with 40dB gain as specified the input required
                          > > > is 0dBm. If the Softrock is 1W out which is 30dBm, then a fixed 30dB
                          > > > attenuator between the Softrock and the complete 10W amplifier
                          should
                          > > > bring the levels in-line.
                          > >
                          > > I've measured the IMD from softrock PA and it is not even near the IMD
                          > > performance of the driver stage from the PLB-15 (KT610: -50dBc) so I
                          > > do not use the SR PA any more, I take direct output from the QSE and
                          > > everything is fine.
                          > > If you put attenuators, then you will just enhance the bad IMD
                          > > performance of the SR PA.
                          > >
                          > > >
                          > > > I notice on the amplifier schematic that the transmit input is
                          labeled
                          > > > as "to BPF" and the output is labeled to LPF. This seems like a
                          > > > non-optimal tx/rx switching arrangement to me; having both filter
                          > > > banks in-line during receive. Hmmm...
                          > >
                          > >
                          > > Probably we are not on the same page here, the PA I mention is
                          > > ->http://www.box73.de/catalog/pdf/PLB-15.pdf
                          > > and it is not saying that.
                          > >
                          >
                        • Mark GM4ISM
                          gents, My findings are similar to Christos, for the RXTX 6.2 The IMD performance is quite poor for the softrock PA I consider it s performance adequate up to
                          Message 12 of 22 , Dec 30, 2008
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                            gents,
                            My findings are similar to Christos, for the RXTX 6.2
                            The IMD performance is quite poor for the softrock PA
                            I consider it's performance adequate up to about 250mW, no more.
                            I have used it on 7MHz for test DRM transmissions, and could only get just under 100mW  with acceptable IPs (> -30dB) For a 1W Pa I would have expected to get within 6 to 7dB if it rating.
                            I would aim to run the softrock PA at about 100mw to drive subsequent stages, of course this takes careful set-up to ensure that the audio drive levels are correctly maintained
                            Regards
                            Mark GM4ISM
                             
                             
                             
                            ----- Original Message -----
                            Sent: Tuesday, December 30, 2008 5:50 PM
                            Subject: [softrock40] Re: 10W Linear amp from Kits & Parts. Anyone tried it with SR yet?

                            I wonder if the bad IMD from the SR PA Christos is reporting is a
                            general finding? I have not encountered any problems (bad IMD reports
                            on hundreds of PSK31 and SSB QSOs) using the SR V 6.2 PA @ 1 W to feed
                            an amplifier. Only if the supply voltage falls much below 12V do I
                            find problems with the transmitted signal.

                            Earl 4Z4TJ

                            --- In softrock40@yahoogro ups.com, "Christos Nikolaou" <sv1eia@...> wrote:
                            >
                            > --- In softrock40@yahoogro ups.com, "drmail377" <drmail377@> wrote:
                            > >
                            > > If the amp is 10W out with 40dB gain as specified the input required
                            > > is 0dBm. If the Softrock is 1W out which is 30dBm, then a fixed 30dB
                            > > attenuator between the Softrock and the complete 10W amplifier should
                            > > bring the levels in-line.
                            >
                            > I've measured the IMD from softrock PA and it is not even near the IMD
                            > performance of the driver stage from the PLB-15 (KT610: -50dBc) so I
                            > do not use the SR PA any more, I take direct output from the QSE and
                            > everything is fine.
                            > If you put attenuators, then you will just enhance the bad IMD
                            > performance of the SR PA.
                            >
                            > >
                            > > I notice on the amplifier schematic that the transmit input is labeled
                            > > as "to BPF" and the output is labeled to LPF. This seems like a
                            > > non-optimal tx/rx switching arrangement to me; having both filter
                            > > banks in-line during receive. Hmmm...
                            >
                            >
                            > Probably we are not on the same page here, the PA I mention is
                            > ->http://www.box73. de/catalog/ pdf/PLB-15. pdf
                            > and it is not saying that.
                            >



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                          • Mike Collins
                            ... about. ... better. Hi Guys and Happy New Year, The Softrock driver and PA stage is kind of average for IMD. I like the IMD performace with the Mits RD
                            Message 13 of 22 , Dec 30, 2008
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                              > If you see in the files section there is a measured ~28dBc IMD from
                              > the SR PA. Compare that to the measurements on the PLB-15 document
                              > (-48dBc to -66dBc)and I hope that you understand what I am talking
                              about.
                              > In my case, I could not reach even the acclaimed -28dBc of the SR PA,
                              > I had more like -20dBc but that might be due to local problems.
                              > Either way the difference (-28dBc to -48dBc) is quite large, so I
                              > decided to scrap the SR PA and stay with the KT610/RD16HHF1 combo
                              > where the IMD to Watts ratio is something that (IMHO) I find much
                              better.

                              Hi Guys and Happy New Year,

                              The Softrock driver and PA stage is kind of average for IMD. I like
                              the IMD performace with the Mits RD parts too.

                              One thing to put in perspective is that in the last several years, the
                              ARRL lab testing has reported TX 3rd order IMD levels from -21dBPEP to
                              -35dBPEP for the "top" commercial rigs. Even the highly desired
                              Elecraft K3 is reported at -27dBPEP, and the ICOM 7700 is -28dBPEP.
                              These are dBPEP numbers which are 6dB "better" than comparing to each
                              tone level. So if you don't like the Softrock TX IMD performance, you
                              better not XMIT with your commercial rig!!

                              73, Mike Collins KF4BQ
                            • cesco12342000
                              ... What does the 100mw refer to? Average or PEP ? If it s average that is what i would expect from a 1W PA. Drm has quite a crest factor. With 100mw average
                              Message 14 of 22 , Dec 30, 2008
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                                > I have used it on 7MHz for test DRM transmissions, and could
                                > only get just under 100mW with acceptable IPs (> -30dB)

                                What does the 100mw refer to? Average or PEP ?

                                If it's average that is what i would expect from a 1W PA. Drm has
                                quite a crest factor. With 100mw average there will be pep values in
                                excess of 1W (clipping).
                              • Mark GM4ISM
                                Hi, the value obtained was actually about 70mw mean power, measured on a modern spectrum analyser with an occupied channel power function Many simple diode
                                Message 15 of 22 , Dec 30, 2008
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                                  Hi, the value obtained was actually about 70mw mean power, measured on a modern spectrum analyser with an occupied channel power function
                                  Many simple diode detectors respond inaccurately to OFDM signals, although thermal power meters are OK.
                                  peak to mean ratio is nominally assumed to be 10dB for multi-carrier  OFDM type signals.  With good precorrection one can obtain good IPs with about 6dB headroom on the amplifier, but I don't have any precorrection available with Spark.
                                  30dB is a rather minimal figure, as a driver be it for SSB or DRM.
                                  I know a lot of commercial rigs are equally poor at the output of the final, and you sure can tell on the air with some stations :<)
                                  My point is that I find the level of IPs at 1w output from the softrock poorer than I am comfortable with when driving an amplifier. IPs don't usually get better if you add another stage.
                                  I would much rather under-run a stage and get good IMD than rely on the max power from each stage as the minimum drive requirement for the next.
                                  Of course with SDR, some clever person could build in precorrection routines :<)  please?
                                  mark GM4ISM
                                   
                                   
                                   
                                   
                                   
                                   
                                  ----- Original Message -----
                                  Sent: Tuesday, December 30, 2008 8:41 PM
                                  Subject: [softrock40] Re: 10W Linear amp from Kits & Parts. Anyone tried it with SR yet?

                                  > I have used it on 7MHz for test DRM transmissions, and could
                                  > only get just under 100mW with acceptable IPs (> -30dB)

                                  What does the 100mw refer to? Average or PEP ?

                                  If it's average that is what i would expect from a 1W PA. Drm has
                                  quite a crest factor. With 100mw average there will be pep values in
                                  excess of 1W (clipping).



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                                • Christos Nikolaou
                                  Hi Mike, I agree that the commercial rigs have these figures. One thing though needs to be noted, the ARRL numbers refer to full power eg 100W whereas here we
                                  Message 16 of 22 , Dec 30, 2008
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                                    Hi Mike,

                                    I agree that the commercial rigs have these figures.
                                    One thing though needs to be noted, the ARRL numbers refer to full
                                    power eg 100W whereas here we have 100mW-1W. :-)

                                    73,
                                    Christos SV1EIA

                                    --- In softrock40@yahoogroups.com, "Mike Collins" <mikecol@...> wrote:
                                    >
                                    > > If you see in the files section there is a measured ~28dBc IMD from
                                    > > the SR PA. Compare that to the measurements on the PLB-15 document
                                    > > (-48dBc to -66dBc)and I hope that you understand what I am talking
                                    > about.
                                    > > In my case, I could not reach even the acclaimed -28dBc of the SR PA,
                                    > > I had more like -20dBc but that might be due to local problems.
                                    > > Either way the difference (-28dBc to -48dBc) is quite large, so I
                                    > > decided to scrap the SR PA and stay with the KT610/RD16HHF1 combo
                                    > > where the IMD to Watts ratio is something that (IMHO) I find much
                                    > better.
                                    >
                                    > Hi Guys and Happy New Year,
                                    >
                                    > The Softrock driver and PA stage is kind of average for IMD. I like
                                    > the IMD performace with the Mits RD parts too.
                                    >
                                    > One thing to put in perspective is that in the last several years, the
                                    > ARRL lab testing has reported TX 3rd order IMD levels from -21dBPEP to
                                    > -35dBPEP for the "top" commercial rigs. Even the highly desired
                                    > Elecraft K3 is reported at -27dBPEP, and the ICOM 7700 is -28dBPEP.
                                    > These are dBPEP numbers which are 6dB "better" than comparing to each
                                    > tone level. So if you don't like the Softrock TX IMD performance, you
                                    > better not XMIT with your commercial rig!!
                                    >
                                    > 73, Mike Collins KF4BQ
                                    >
                                  • sivan_toledo
                                    Christos, how do you connect the output of the QSE to the PLB-15 ampifier? Do you use the tuned transformer of the SR between them? Thanks, Sivan
                                    Message 17 of 22 , Dec 31, 2008
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                                      Christos, how do you connect the output of the QSE to the PLB-15
                                      ampifier? Do you use the tuned transformer of the SR between them?

                                      Thanks, Sivan

                                      --- In softrock40@yahoogroups.com, "Christos Nikolaou" <sv1eia@...> wrote:
                                      >
                                      > I've measured the IMD from softrock PA and it is not even near the IMD
                                      > performance of the driver stage from the PLB-15 (KT610: -50dBc) so I
                                      > do not use the SR PA any more, I take direct output from the QSE and
                                      > everything is fine.
                                      > If you put attenuators, then you will just enhance the bad IMD
                                      > performance of the SR PA.
                                      >
                                      > ...
                                    • dick_faust
                                      ... Here is another 20W option based upon the G6ALU design for Pic-A-Star http://hpsdr.org/pennywhistle.html More info at the wiki
                                      Message 18 of 22 , Dec 31, 2008
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                                        --- In softrock40@yahoogroups.com, "drmail377" <drmail377@...> wrote:
                                        >
                                        > At:
                                        >
                                        > http://kitsandparts.com/linearamp.php
                                        >
                                        > There's a 10W HF linear (CW/SSB) amplifier kit that looks like it will
                                        > drive with +1dBm. A 5W kit is coming out in January 2009. There are
                                        > LPF and BPF kits available on the site as well.
                                        >
                                        > Has anyone tried one of these with a Softrock radio yet?
                                        >
                                        > 73's David
                                        >
                                        Here is another 20W option based upon the G6ALU design for Pic-A-Star
                                        http://hpsdr.org/pennywhistle.html
                                        More info at the wiki
                                        http://hpsdr.org/wiki/index.php?title=PENNYWHISTLE
                                        Dick K9IVB
                                      • Christos Nikolaou
                                        Hi Sivan, From the secondary winding of the QSE transformer get it with a .1uF blocking capacitor. In my case I ve also removed the provided transformer and
                                        Message 19 of 22 , Dec 31, 2008
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                                          Hi Sivan,

                                          From the secondary winding of the QSE transformer get it with a .1uF
                                          blocking capacitor.

                                          In my case I've also removed the provided transformer and placed a
                                          broadband MiniCircuits one in both Rx and Tx. You do not need to do
                                          that if you plan to have only the band that the SR is designed to.

                                          Best wishes for a Happy New Year
                                          Christos SV1EIA



                                          --- In softrock40@yahoogroups.com, "sivan_toledo" <sivan.toledo@...>
                                          wrote:
                                          >
                                          > Christos, how do you connect the output of the QSE to the PLB-15
                                          > ampifier? Do you use the tuned transformer of the SR between them?
                                          >
                                          > Thanks, Sivan
                                          >
                                          > --- In softrock40@yahoogroups.com, "Christos Nikolaou" <sv1eia@> wrote:
                                          > >
                                          > > I've measured the IMD from softrock PA and it is not even near the IMD
                                          > > performance of the driver stage from the PLB-15 (KT610: -50dBc) so I
                                          > > do not use the SR PA any more, I take direct output from the QSE and
                                          > > everything is fine.
                                          > > If you put attenuators, then you will just enhance the bad IMD
                                          > > performance of the SR PA.
                                          > >
                                          > > ...
                                          >
                                        • sivan_toledo
                                          Thanks, that s exactly what I wanted to know. I wanted to try something like this out but was wondering whether the tuned transformer was serving some
                                          Message 20 of 22 , Jan 1, 2009
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                                            Thanks, that's exactly what I wanted to know. I wanted to try
                                            something like this out but was wondering whether the tuned
                                            transformer was serving some necessary filtering function between the
                                            mixer and the driver and PA. From your reply I understand that a
                                            broadband path all the way from the mixer to the output LPF should
                                            work fine.

                                            Happy New Year, Sivan

                                            --- In softrock40@yahoogroups.com, "Christos Nikolaou" <sv1eia@...> wrote:
                                            >
                                            > Hi Sivan,
                                            >
                                            > From the secondary winding of the QSE transformer get it with a .1uF
                                            > blocking capacitor.
                                            >
                                            > In my case I've also removed the provided transformer and placed a
                                            > broadband MiniCircuits one in both Rx and Tx. You do not need to do
                                            > that if you plan to have only the band that the SR is designed to.
                                            >
                                            > Best wishes for a Happy New Year
                                            > Christos SV1EIA
                                            >
                                            >
                                            >
                                            > --- In softrock40@yahoogroups.com, "sivan_toledo" <sivan.toledo@>
                                            > wrote:
                                            > >
                                            > > Christos, how do you connect the output of the QSE to the PLB-15
                                            > > ampifier? Do you use the tuned transformer of the SR between them?
                                            > >
                                            > > Thanks, Sivan
                                            > >
                                            > > --- In softrock40@yahoogroups.com, "Christos Nikolaou" <sv1eia@>
                                            wrote:
                                            > > >
                                            > > > I've measured the IMD from softrock PA and it is not even near
                                            the IMD
                                            > > > performance of the driver stage from the PLB-15 (KT610: -50dBc)
                                            so I
                                            > > > do not use the SR PA any more, I take direct output from the QSE and
                                            > > > everything is fine.
                                            > > > If you put attenuators, then you will just enhance the bad IMD
                                            > > > performance of the SR PA.
                                            > > >
                                            > > > ...
                                            > >
                                            >
                                          • M0FMT
                                            Hi Christos (SV1EIA)   Tnx for the idea. Could you publish details like PN for the xformer etc?   Many thanks and Happy New Year to you and all on list and
                                            Message 21 of 22 , Jan 1, 2009
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                                              Hi Christos (SV1EIA)
                                               
                                              Tnx for the idea. Could you publish details like PN for the xformer etc?
                                               
                                              Many thanks and Happy New Year to you and all on list and Tony of course.
                                               
                                              73 petefmt
                                               
                                               

                                            • Christos Nikolaou
                                              This is used already in SDR-1000 in the QSE/QSD so it is a proven one http://www.minicircuits.com/pdfs/T4-1.pdf ... etc? ... course.
                                              Message 22 of 22 , Jan 1, 2009
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                                                This is used already in SDR-1000 in the QSE/QSD so it is a proven one

                                                http://www.minicircuits.com/pdfs/T4-1.pdf



                                                --- In softrock40@yahoogroups.com, M0FMT <m0fmt@...> wrote:
                                                >
                                                > Hi Christos (SV1EIA)
                                                >  
                                                > Tnx for the idea. Could you publish details like PN for the xformer
                                                etc?
                                                >  
                                                > Many thanks and Happy New Year to you and all on list and Tony of
                                                course.
                                                >  
                                                > 73 petefmt
                                                >  
                                                >  
                                                >
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