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Making a SoftRock V6 and similar Multiband HF SDR RX

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  • Giancarlo
    Hi all, as promised to Kees a couple of weeks ago, I have arranged for a specific document reporting my idea of Digital Quadrature Generator with manual phase
    Message 1 of 25 , Apr 20 7:15 AM
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      Hi all,

      as promised to Kees a couple of weeks ago, I have arranged for a
      specific document reporting my idea of Digital Quadrature Generator
      with manual phase adjustment using a Local Oscillator with a
      frequency equal to Twice the Fundamental frequency required. This
      solution covers 1 to 30MHz and requires a VFO or DDS operating
      between 2MHz to 60MHz. The ideal solution for a DDS-60.
      Certainly we have vto compromise. All instruction to mods and
      adjustments are reported in the document loaded in File.
      You have also circuit diagram and screen shots using Winrad at taken
      at different bands.
      The 14MHz screen shots have the manual and the additional Winrad
      software adjustment.

      File: I7SWX_DQG_2xFo_HF improvexSoftRock.pdf

      Enjoy the reading and experimenting with it.

      73

      Gian
      I7SWX
    • Len Warner
      ... 5.1. New file uploaded to softrock40 ... Great work, Gian. A minor correction: page 2 says; ... The feedback resistors are shown as 4.99K in the schematic
      Message 2 of 25 , Apr 22 11:47 PM
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        At 08:44 07/04/21, Digest Number 1578 wrote:
        >4. Making a SoftRock V6 and similar Multiband HF SDR RX
        > Posted by: "Giancarlo" i7swx@... i7swx
        > Date: Fri Apr 20, 2007 7:16 am ((PDT))
        >
        >solution covers 1 to 30MHz and requires a VFO or DDS operating
        >between 2MHz to 60MHz.

        5.1. New file uploaded to softrock40
        > File : /I7SWX_DQG_2xFo_HF improvxSoftRock.pdf
        > Description : This is a note on how to modify a SoftRockV6 and similar
        > QSDs to operate as a Multiband HF SDR RX 73 Gian I7SWX
        >
        >You can access this file at the URL:
        >http://groups.yahoo.com/group/softrock40/files/I7SWX_DQG_2xFo_HF%20improvxSoftRock.pdf
        >

        Great work, Gian. A minor correction: page 2 says;

        > GAIN REDUCTION
        > I have also implemented a drastic gain reduction on the SoftRock V6
        > to reduce ADC saturation. I have added a 1.2kohm resistor in parallel
        > to each 49.9K feedback resistors on the OPAs.

        The feedback resistors are shown as 4.99K in the schematic so
        it's not as drastic a gain reduction as you seem to suggest ;-)


        Regards, LenW
        --
        Please trim quotes to minimum for context, then
        reply _below_ or interleave point-by-point replies.
      • Giancarlo
        ... similar ... 20improvxSoftRock.pdf ... Thanks Len, A minor correction: page 2 says; ... V6 ... parallel ... Yes, you are right .... 4.99K vs 49.9K like in
        Message 3 of 25 , Apr 23 3:24 AM
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          --- In softrock40@yahoogroups.com, Len Warner <novost@...> wrote:
          >
          > At 08:44 07/04/21, Digest Number 1578 wrote:
          > >4. Making a SoftRock V6 and similar Multiband HF SDR RX
          > > Posted by: "Giancarlo" i7swx@... i7swx
          > > Date: Fri Apr 20, 2007 7:16 am ((PDT))
          > >
          > >solution covers 1 to 30MHz and requires a VFO or DDS operating
          > >between 2MHz to 60MHz.
          >
          > 5.1. New file uploaded to softrock40
          > > File : /I7SWX_DQG_2xFo_HF improvxSoftRock.pdf
          > > Description : This is a note on how to modify a SoftRockV6 and
          similar
          > > QSDs to operate as a Multiband HF SDR RX 73 Gian I7SWX
          > >
          > >You can access this file at the URL:
          > >http://groups.yahoo.com/group/softrock40/files/I7SWX_DQG_2xFo_HF%
          20improvxSoftRock.pdf
          > >
          >
          > Great work, Gian.

          Thanks Len,


          A minor correction: page 2 says;
          >
          > > GAIN REDUCTION
          > > I have also implemented a drastic gain reduction on the SoftRock
          V6
          > > to reduce ADC saturation. I have added a 1.2kohm resistor in
          parallel
          > > to each 49.9K feedback resistors on the OPAs.
          >
          > The feedback resistors are shown as 4.99K in the schematic so
          > it's not as drastic a gain reduction as you seem to suggest ;-)

          Yes, you are right .... 4.99K vs 49.9K like in the SR V7 ... not so
          drastic...hi I will make correction.

          73

          Gian
          I7SWX




          >
          > Regards, LenW
          > --
          > Please trim quotes to minimum for context, then
          > reply _below_ or interleave point-by-point replies.
          >
        • neomag_magneo
          Dear Gian, Some comments/ questions about the multiband approach for Softrock. I have not constructed any SDR equipment yet (too busy with my other projects,
          Message 4 of 25 , Apr 24 2:36 AM
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            Dear Gian,

            Some comments/ questions about the multiband approach for Softrock. I
            have not constructed any SDR equipment yet (too busy with my other
            projects, see the EMRFD group), but strongly condsidering either a
            stand-alone RX/TX or a softrock module for IF processing.

            1) The divide-by-4 for the quadrature LO is quite feasible for the
            multiband also. If we forget the upper bands, 0-60 MHz LO available
            easily from an AD9951 is sufficient for 20 mb and below.

            2) The squarer/divider introduced in your article has a phasing
            adjustment. When compared with div-by-4, is this an advantage or a
            disadvantage. What I mean, in reality, can you expect to get better
            performance from a div-by-4 without any adjustments at all ?

            3) In your opinion, is there any difference in performance between the
            MUX circuits and the quad switches. It seems to me that the only
            practical difference is the LO signals required (2 phases contra 4
            phases). Since I do not anticipate to purchase any kits, I am quite
            free to choose the circuits and their combinations according to the
            availability and my own needs.

            4) About the AD9951 (although there is another group for this). My
            success rate with this chip is 50 % (one working, one failure). With
            the older 9850/1 the rate was 100 % (4 units working), are the new
            chips less tolerant for short circuits, overvoltages etc. If s, I may
            need take special precautions with my next trial, since there is not
            much You can do when the chip turns out to be dead !!!


            BR Heikki (OH2LZI)

            P.S. I have not tried the 2-T H-mode mixer yet but it is in my list !
            Unfortunately (???), the summer is approaching with more outdoor
            related activities...
          • Giancarlo
            Hi Heikki, thanks for your message. Your uestions are interesting and need to be answered properly (or as best as possible at least from me. I am sure there
            Message 5 of 25 , Apr 25 2:44 AM
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              Hi Heikki,

              thanks for your message. Your uestions are interesting and need to be
              answered properly (or as best as possible at least from me. I am sure
              there are others members of this group that can add comments)

              --- In softrock40@yahoogroups.com, "neomag_magneo" <oh2lzi@...> wrote:
              >
              > Dear Gian,
              >
              > Some comments/ questions about the multiband approach for Softrock.
              I
              > have not constructed any SDR equipment yet (too busy with my other
              > projects, see the EMRFD group), but strongly condsidering either a
              > stand-alone RX/TX or a softrock module for IF processing.

              I do believe a Softrock is a very interesting IF module. If you
              obviate to the large receiving bandwidth it can be used followed by a
              DSP-10 and avoid the use of a PC.

              >
              > 1) The divide-by-4 for the quadrature LO is quite feasible for the
              > multiband also. If we forget the upper bands, 0-60 MHz LO available
              > easily from an AD9951 is sufficient for 20 mb and below.

              Certainly the best quadrature signals are given by a divide by four.
              Again, forgetting the 50 MHz coverage ... with div-by-4 you still
              need an LO to generate 120 MHz. Not everyone has or can afford the
              buildin of a DDS using AD9951 (I0CG Design covers up to 200MHz). Many
              hams have already oscillators, PLL or DDS covering up to 60 MHz, like
              the DDS-60 by AmQRP.
              I am always looking to simple solutions although for these need
              to "compromise" ... we are not doing commercial business so
              compromise is not a negative solution. Then someone said SDR do not
              have knobs... well I7SWX says well we can have SDR with two knobs...
              LO and Manual phase adjustment ... (please forgive me for this) ...hi

              >
              > 2) The squarer/divider introduced in your article has a phasing
              > adjustment. When compared with div-by-4, is this an advantage or a
              > disadvantage. What I mean, in reality, can you expect to get better
              > performance from a div-by-4 without any adjustments at all ?

              I am not sure as I have not yet compared it with a divide by four.
              What I believe is that it could reduce the disadvantages between the
              two. It needs comparison.

              >
              > 3) In your opinion, is there any difference in performance between
              the
              > MUX circuits and the quad switches. It seems to me that the only
              > practical difference is the LO signals required (2 phases contra 4
              > phases).

              Again it is not an easy answer as we dio need to make comparisons
              between similar solution. I.e to compare the same circuit like SR V6
              using Mux FST3253 and FST3125 with 74AC00 decoder.
              The MUX internal decoding cannot be controlled as it may be possible,
              or not, with the 3125 and 00. With the manual adjustment we have the
              good adjustment of quadrature between 0° and 90° and also "correct"
              any unbalance of chip internal switching. On teh SR V6 I have better
              image rejection than the original div-by 4 solution at 7MHz, 5 to
              10dB.
              With the 4 phases we have the adjustment of quadrature between 0° and
              90° or 180° and 270° but not between all four phases. Going up on
              frequency the Q and NotQ phase is becoming a problem as it is not
              really complementary as normally there is a delay of 100pS (0.1nS)
              between the two when switching. I guess in the MUX this difference
              could be higher (???).
              I am working on a different kind of I-Q mixer that is apparently
              givig me and hdw image rejection around 60dB (<70) using the divide
              by two with manual adjustment. Winrad can reject into the LIVE24 USB
              noise line with a very small amplitude adjustment and a small phase
              adjust of less than 0.2° at 14MHz (28MHz LO).


              > Since I do not anticipate to purchase any kits, I am quite
              > free to choose the circuits and their combinations according to the
              > availability and my own needs.

              I do believe it is not necessary to purchase any kit if you can do
              your own PCB or ugly assy (like I do).

              > 4) About the AD9951 (although there is another group for this). My
              > success rate with this chip is 50 % (one working, one failure). With
              > the older 9850/1 the rate was 100 % (4 units working), are the new
              > chips less tolerant for short circuits, overvoltages etc. If s, I
              may
              > need take special precautions with my next trial, since there is not
              > much You can do when the chip turns out to be dead !!!

              I am sorry for the 50-50 (complementary) failures with AD9951. This
              DDS require an industrial type of PCB to reduce problems and in
              particular spur and also a very high frequency external X.O., the
              I0CG design is using an external oscillator of 500MHz and a special
              designed PCB.

              >
              >
              > BR Heikki (OH2LZI)
              >
              > P.S. I have not tried the 2-T H-mode mixer yet but it is in my
              list !

              I am sure you will enjoy the tial like done by many hams worldwide.

              > Unfortunately (???), the summer is approaching with more outdoor
              > related activities...

              Too bad for you ... but you could have a little tables outside your
              house and do some soldering ... like I do during the summer...hi

              73

              and keep all of us posted on your projects...there is always
              osmething to learn sharing information. To give you an idea.. a DL
              friend has applied a 2 T H-Mode Mixer mod to the 1st mixer and also
              1st IF mod to his TS940 ... and it has changed from night to day...

              73

              Gian
              I7SWX

              Solder and smokes are the future of amateur radio ... I blew up a lot
              of chips ...hi
              >
            • tom_iphi
              Hi Gian, have you ever performed IP3 measurements on your 2 T H-Mode Mixer ? 73, Tom DG8SAQ ... be ... sure ... Softrock. ... a ... available ... Many ... like
              Message 6 of 25 , Apr 25 7:31 AM
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                Hi Gian,

                have you ever performed IP3 measurements on your 2 T H-Mode Mixer ?

                73, Tom DG8SAQ


                --- In softrock40@yahoogroups.com, "Giancarlo" <i7swx@...> wrote:
                >
                > Hi Heikki,
                >
                > thanks for your message. Your uestions are interesting and need to
                be
                > answered properly (or as best as possible at least from me. I am
                sure
                > there are others members of this group that can add comments)
                >
                > --- In softrock40@yahoogroups.com, "neomag_magneo" <oh2lzi@> wrote:
                > >
                > > Dear Gian,
                > >
                > > Some comments/ questions about the multiband approach for
                Softrock.
                > I
                > > have not constructed any SDR equipment yet (too busy with my other
                > > projects, see the EMRFD group), but strongly condsidering either a
                > > stand-alone RX/TX or a softrock module for IF processing.
                >
                > I do believe a Softrock is a very interesting IF module. If you
                > obviate to the large receiving bandwidth it can be used followed by
                a
                > DSP-10 and avoid the use of a PC.
                >
                > >
                > > 1) The divide-by-4 for the quadrature LO is quite feasible for the
                > > multiband also. If we forget the upper bands, 0-60 MHz LO
                available
                > > easily from an AD9951 is sufficient for 20 mb and below.
                >
                > Certainly the best quadrature signals are given by a divide by four.
                > Again, forgetting the 50 MHz coverage ... with div-by-4 you still
                > need an LO to generate 120 MHz. Not everyone has or can afford the
                > buildin of a DDS using AD9951 (I0CG Design covers up to 200MHz).
                Many
                > hams have already oscillators, PLL or DDS covering up to 60 MHz,
                like
                > the DDS-60 by AmQRP.
                > I am always looking to simple solutions although for these need
                > to "compromise" ... we are not doing commercial business so
                > compromise is not a negative solution. Then someone said SDR do not
                > have knobs... well I7SWX says well we can have SDR with two
                knobs...
                > LO and Manual phase adjustment ... (please forgive me for
                this) ...hi
                >
                > >
                > > 2) The squarer/divider introduced in your article has a phasing
                > > adjustment. When compared with div-by-4, is this an advantage or a
                > > disadvantage. What I mean, in reality, can you expect to get
                better
                > > performance from a div-by-4 without any adjustments at all ?
                >
                > I am not sure as I have not yet compared it with a divide by four.
                > What I believe is that it could reduce the disadvantages between
                the
                > two. It needs comparison.
                >
                > >
                > > 3) In your opinion, is there any difference in performance
                between
                > the
                > > MUX circuits and the quad switches. It seems to me that the only
                > > practical difference is the LO signals required (2 phases contra 4
                > > phases).
                >
                > Again it is not an easy answer as we dio need to make comparisons
                > between similar solution. I.e to compare the same circuit like SR
                V6
                > using Mux FST3253 and FST3125 with 74AC00 decoder.
                > The MUX internal decoding cannot be controlled as it may be
                possible,
                > or not, with the 3125 and 00. With the manual adjustment we have
                the
                > good adjustment of quadrature between 0° and 90° and also "correct"
                > any unbalance of chip internal switching. On teh SR V6 I have
                better
                > image rejection than the original div-by 4 solution at 7MHz, 5 to
                > 10dB.
                > With the 4 phases we have the adjustment of quadrature between 0°
                and
                > 90° or 180° and 270° but not between all four phases. Going up on
                > frequency the Q and NotQ phase is becoming a problem as it is not
                > really complementary as normally there is a delay of 100pS (0.1nS)
                > between the two when switching. I guess in the MUX this difference
                > could be higher (???).
                > I am working on a different kind of I-Q mixer that is apparently
                > givig me and hdw image rejection around 60dB (<70) using the divide
                > by two with manual adjustment. Winrad can reject into the LIVE24
                USB
                > noise line with a very small amplitude adjustment and a small phase
                > adjust of less than 0.2° at 14MHz (28MHz LO).
                >
                >
                > > Since I do not anticipate to purchase any kits, I am quite
                > > free to choose the circuits and their combinations according to
                the
                > > availability and my own needs.
                >
                > I do believe it is not necessary to purchase any kit if you can do
                > your own PCB or ugly assy (like I do).
                >
                > > 4) About the AD9951 (although there is another group for this). My
                > > success rate with this chip is 50 % (one working, one failure).
                With
                > > the older 9850/1 the rate was 100 % (4 units working), are the new
                > > chips less tolerant for short circuits, overvoltages etc. If s, I
                > may
                > > need take special precautions with my next trial, since there is
                not
                > > much You can do when the chip turns out to be dead !!!
                >
                > I am sorry for the 50-50 (complementary) failures with AD9951. This
                > DDS require an industrial type of PCB to reduce problems and in
                > particular spur and also a very high frequency external X.O., the
                > I0CG design is using an external oscillator of 500MHz and a special
                > designed PCB.
                >
                > >
                > >
                > > BR Heikki (OH2LZI)
                > >
                > > P.S. I have not tried the 2-T H-mode mixer yet but it is in my
                > list !
                >
                > I am sure you will enjoy the tial like done by many hams worldwide.
                >
                > > Unfortunately (???), the summer is approaching with more outdoor
                > > related activities...
                >
                > Too bad for you ... but you could have a little tables outside your
                > house and do some soldering ... like I do during the summer...hi
                >
                > 73
                >
                > and keep all of us posted on your projects...there is always
                > osmething to learn sharing information. To give you an idea.. a DL
                > friend has applied a 2 T H-Mode Mixer mod to the 1st mixer and also
                > 1st IF mod to his TS940 ... and it has changed from night to day...
                >
                > 73
                >
                > Gian
                > I7SWX
                >
                > Solder and smokes are the future of amateur radio ... I blew up a
                lot
                > of chips ...hi
                > >
                >
              • Chris Albertson
                Maybe the answer is on fig 27, page 24 of the AD9951 data sheet? It shows how to make I and Q signals without using a divide by 4. What they do is sync two
                Message 7 of 25 , Apr 25 10:13 AM
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                  Maybe the answer is on fig 27, page 24 of the AD9951 data sheet?

                  It shows how to make I and Q signals without using a divide by 4.
                  What they do is sync two AD9951 and program one of them to be 90 out of
                  phase. The phase is under software control and can be anything you
                  want.

                  When you use a pair of DDS chips like this you can run them with
                  reduces REFCLK frequency. 4x slower then if you where feeding a devide
                  by four system. With a 20X multiplier selected you can get by using a
                  5Mhz Crystal (I think)

                  Yes, using two DDS chips is more expensive but only by the cost of one
                  chip ($13) and you save the phase adjustment stuff by directly
                  producing what you want




                  Chris Albertson
                  Home: 310-376-1029 chrisalbertson90278@...
                  Office: 310-336-5189 Christopher.J.Albertson@...

                  __________________________________________________
                  Do You Yahoo!?
                  Tired of spam? Yahoo! Mail has the best spam protection around
                  http://mail.yahoo.com
                • Giancarlo
                  ... Hi Tom, Yes, I have done measurement like others OM too. The G3XJP STAR using the 2T H-Mode Mixer has an IP3 of 36 or 38dBm. You may look at my web site
                  Message 8 of 25 , Apr 26 6:49 AM
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                    --- In softrock40@yahoogroups.com, "tom_iphi" <iphi@...> wrote:
                    >
                    > Hi Gian,
                    >
                    > have you ever performed IP3 measurements on your 2 T H-Mode Mixer ?
                    >
                    > 73, Tom DG8SAQ
                    >
                    >

                    Hi Tom,

                    Yes, I have done measurement like others OM too.

                    The G3XJP STAR using the 2T H-Mode Mixer has an IP3 of 36 or 38dBm.

                    You may look at my web site (not updated) www.qsl.net/i7swx look at
                    homebrew and will see the measurements done by JA9TTT or directly at
                    the JA9TTT web page.

                    I have loaded in Files a diagram of measurements done by I4SBX and
                    published in Radio Kit Elettronica (italian magazine march-april 2007)
                    You will see IMD measurments done comparing a 3T vs 2T using
                    different transformers (windings) the basic line of reference is
                    +40dBm

                    73

                    Gian
                    I7SWX
                  • tom_iphi
                    Hi Gian, thanks! The numbers are impressive! I m not sure if I really understand the plot you have posted: Does it show 3rd order IM mixer output power versus
                    Message 9 of 25 , Apr 26 12:32 PM
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                      Hi Gian,

                      thanks! The numbers are impressive!
                      I'm not sure if I really understand the plot you have posted:
                      Does it show 3rd order IM mixer output power versus mixer input power?

                      73, Tom DG8SAQ


                      > Hi Tom,
                      >
                      > Yes, I have done measurement like others OM too.
                      >
                      > The G3XJP STAR using the 2T H-Mode Mixer has an IP3 of 36 or 38dBm.
                      >
                      > You may look at my web site (not updated) www.qsl.net/i7swx look
                      at
                      > homebrew and will see the measurements done by JA9TTT or directly
                      at
                      > the JA9TTT web page.
                      >
                      > I have loaded in Files a diagram of measurements done by I4SBX and
                      > published in Radio Kit Elettronica (italian magazine march-april
                      2007)
                      > You will see IMD measurments done comparing a 3T vs 2T using
                      > different transformers (windings) the basic line of reference is
                      > +40dBm
                      >
                      > 73
                      >
                      > Gian
                      > I7SWX
                      >
                    • Giancarlo
                      ... Hi Tom, Yes, impressive numbers! The plot is simple ... hi... well in the bottom horizontal line you have the input power in dBm, while on the vertical the
                      Message 10 of 25 , Apr 27 8:00 AM
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                        --- In softrock40@yahoogroups.com, "tom_iphi" <iphi@...> wrote:
                        >
                        > Hi Gian,
                        >
                        > thanks! The numbers are impressive!
                        > I'm not sure if I really understand the plot you have posted:
                        > Does it show 3rd order IM mixer output power versus mixer input power?
                        >
                        > 73, Tom DG8SAQ
                        >

                        Hi Tom,

                        Yes, impressive numbers!

                        The plot is simple ... hi... well in the bottom horizontal line you
                        have the input power in dBm, while on the vertical the IMD 3rd order
                        values in dBm. From there you can calculate the IP3.
                        One of the interesting measurements done by I4SBX is the finding that
                        for input signal over +5dBm the curves do not respond anymore to the
                        3rd order but get steeper. This maybe due to the cores material (????)
                        but same risults are for grade #61; also a similar reaction is obtained
                        using toroids as core.

                        Hope to have clarified your questions.

                        Many friends have applied H-Mode Mixer replacement to commercial
                        equipment with results varying from very large improvement to not so
                        high as expected. Generally this latter problems is associated with
                        phase noise of PLL and LOs.
                        A TR7 was modified and the vy noisy PLL forced the owner to replace it
                        with a AD9951 DDS from I0CG.
                        A 1st Mixer mod on an IC706 risulted in an IP3 improvement of around
                        15dB while replacing the 1st LO with a Xtal Oscillator the improvement
                        was nearly as high as the H-Mode Mixer IP3, something around 30dB.
                        On the K2 from +15dBm (SBL1 with LO +7dBm)it went to +27dBm with 0dBm
                        LO, taking into account the 2t h-mode mixer was followed by a 2xtal
                        roofing filter so not a proper termination.

                        I believe the best is to do your own experimenting with the H-Mode
                        Mixer without listening too much to I7SWX ...hi

                        73

                        Gian
                        I7SWX
                      • Giancarlo
                        ... out of ... devide ... using a ... one
                        Message 11 of 25 , Apr 27 8:27 AM
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                          --- In softrock40@yahoogroups.com, Chris Albertson
                          <chrisalbertson90278@...> wrote:
                          >
                          > Maybe the answer is on fig 27, page 24 of the AD9951 data sheet?
                          >
                          > It shows how to make I and Q signals without using a divide by 4.
                          > What they do is sync two AD9951 and program one of them to be 90
                          out of
                          > phase. The phase is under software control and can be anything you
                          > want.
                          >
                          > When you use a pair of DDS chips like this you can run them with
                          > reduces REFCLK frequency. 4x slower then if you where feeding a
                          devide
                          > by four system. With a 20X multiplier selected you can get by
                          using a
                          > 5Mhz Crystal (I think)
                          >
                          > Yes, using two DDS chips is more expensive but only by the cost of
                          one
                          > chip ($13) and you save the phase adjustment stuff by directly
                          > producing what you want
                          >
                          >
                          >
                          >
                          > Chris Albertson
                          > Home: 310-376-1029 chrisalbertson90278@...
                          > Office: 310-336-5189 Christopher.J.Albertson@...
                          >
                          > __________________________________________________
                          > Do You Yahoo!?
                          > Tired of spam? Yahoo! Mail has the best spam protection around
                          > http://mail.yahoo.com
                          >
                        • tom_iphi
                          Hi Gian, thanks for your explanation. Now I fully understand the picture. I am currently doing my own experiments with mixers and I found that it s not so easy
                          Message 12 of 25 , Apr 27 12:00 PM
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                            Hi Gian,

                            thanks for your explanation. Now I fully understand the picture.
                            I am currently doing my own experiments with mixers and I found that
                            it's not so easy to measure IP3, even with proffesional test
                            equipment.

                            My HP spectrum analyzer only has about 70dB of IMD free dynamic range
                            and I can produce about a 10dBm IMD free two tone signal. So my
                            measurements are limited to about +35dBm IP3.

                            For training I took a TFM2 7dBm mixer and measured about 5dBm of IP3.
                            Strange thing: when I pump it with 20dBm LO power instead of 7dBm I
                            see 30dBm IP3. I'm not sure if this is an artefact or real. I also
                            tried to do an IP3 measurement on softrock, but failed so far. The
                            only source for nonlinearity I could spot was limiting of the IF
                            OpAmp. I wouldn't have had to use a spectrum analyzer on that. It can
                            be seen with a scope, too.

                            You mention improvements due to lower phase noise LOs. That has
                            nothing to do with IP3, right? You just get higher sensitivity next
                            to strong stations with lower phase noise LOs, correct?

                            Has ever anyone built a mixer with a high power MOSFET like IRF510?

                            73, Tom DG8SAQ

                            --- In softrock40@yahoogroups.com, "Giancarlo" <i7swx@...> wrote:
                            >
                            > --- In softrock40@yahoogroups.com, "tom_iphi" <iphi@> wrote:
                            > >
                            > > Hi Gian,
                            > >
                            > > thanks! The numbers are impressive!
                            > > I'm not sure if I really understand the plot you have posted:
                            > > Does it show 3rd order IM mixer output power versus mixer input
                            power?
                            > >
                            > > 73, Tom DG8SAQ
                            > >
                            >
                            > Hi Tom,
                            >
                            > Yes, impressive numbers!
                            >
                            > The plot is simple ... hi... well in the bottom horizontal line you
                            > have the input power in dBm, while on the vertical the IMD 3rd
                            order
                            > values in dBm. From there you can calculate the IP3.
                            > One of the interesting measurements done by I4SBX is the finding
                            that
                            > for input signal over +5dBm the curves do not respond anymore to
                            the
                            > 3rd order but get steeper. This maybe due to the cores material
                            (????)
                            > but same risults are for grade #61; also a similar reaction is
                            obtained
                            > using toroids as core.
                            >
                            > Hope to have clarified your questions.
                            >
                            > Many friends have applied H-Mode Mixer replacement to commercial
                            > equipment with results varying from very large improvement to not
                            so
                            > high as expected. Generally this latter problems is associated with
                            > phase noise of PLL and LOs.
                            > A TR7 was modified and the vy noisy PLL forced the owner to replace
                            it
                            > with a AD9951 DDS from I0CG.
                            > A 1st Mixer mod on an IC706 risulted in an IP3 improvement of
                            around
                            > 15dB while replacing the 1st LO with a Xtal Oscillator the
                            improvement
                            > was nearly as high as the H-Mode Mixer IP3, something around 30dB.
                            > On the K2 from +15dBm (SBL1 with LO +7dBm)it went to +27dBm with
                            0dBm
                            > LO, taking into account the 2t h-mode mixer was followed by a 2xtal
                            > roofing filter so not a proper termination.
                            >
                            > I believe the best is to do your own experimenting with the H-Mode
                            > Mixer without listening too much to I7SWX ...hi
                            >
                            > 73
                            >
                            > Gian
                            > I7SWX
                            >
                          • tom_iphi
                            P.S. ... From that I can only calculate the IP3 if I know the conversion loss of the mixer. Example: Say 10dBm input power, 6dB conversion loss = 4dBm output
                            Message 13 of 25 , Apr 27 12:06 PM
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                              P.S.

                              > The plot is simple ... hi... well in the bottom horizontal line you
                              > have the input power in dBm, while on the vertical the IMD 3rd order
                              > values in dBm. From there you can calculate the IP3.

                              From that I can only calculate the IP3 if I know the conversion loss of
                              the mixer.
                              Example:
                              Say 10dBm input power, 6dB conversion loss
                              => 4dBm output power
                              IMD3 at -50dBm
                              => IMD3 at -54dBc on output
                              => Input IP3 = 10dBm +54/2dBm = 37dBm

                              correct?

                              Tom DG8SAQ
                            • FRANCIS CARCIA
                              Tom, You will take out the diodes of that mixer after a while. I blew one with 16 diodes and series resistors with each diode bank. Type 3A DBM. I hit it with
                              Message 14 of 25 , Apr 27 3:47 PM
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                                Tom,
                                You will take out the diodes of that mixer after a while. I blew one with 16 diodes and series resistors with each diode bank. Type 3A  DBM. I hit it with a good watt. how about using FETs like CP640s. IRF510 will want some serious drive at the gates but sounds like a cool ideal...frank

                                tom_iphi <iphi@...> wrote:
                                Hi Gian,

                                thanks for your explanation. Now I fully understand the picture.
                                I am currently doing my own experiments with mixers and I found that
                                it's not so easy to measure IP3, even with proffesional test
                                equipment.

                                My HP spectrum analyzer only has about 70dB of IMD free dynamic range
                                and I can produce about a 10dBm IMD free two tone signal. So my
                                measurements are limited to about +35dBm IP3.

                                For training I took a TFM2 7dBm mixer and measured about 5dBm of IP3.
                                Strange thing: when I pump it with 20dBm LO power instead of 7dBm I
                                see 30dBm IP3. I'm not sure if this is an artefact or real. I also
                                tried to do an IP3 measurement on softrock, but failed so far. The
                                only source for nonlinearity I could spot was limiting of the IF
                                OpAmp. I wouldn't have had to use a spectrum analyzer on that. It can
                                be seen with a scope, too.

                                You mention improvements due to lower phase noise LOs. That has
                                nothing to do with IP3, right? You just get higher sensitivity next
                                to strong stations with lower phase noise LOs, correct?

                                Has ever anyone built a mixer with a high power MOSFET like IRF510?

                                73, Tom DG8SAQ

                                --- In softrock40@yahoogro ups.com, "Giancarlo" <i7swx@...> wrote:
                                >
                                > --- In softrock40@yahoogro ups.com, "tom_iphi" <iphi@> wrote:
                                > >
                                > > Hi Gian,
                                > >
                                > > thanks! The numbers are impressive!
                                > > I'm not sure if I really understand the plot you have posted:
                                > > Does it show 3rd order IM mixer output power versus mixer input
                                power?
                                > >
                                > > 73, Tom DG8SAQ
                                > >
                                >
                                > Hi Tom,
                                >
                                > Yes, impressive numbers!
                                >
                                > The plot is simple ... hi... well in the bottom horizontal line you
                                > have the input power in dBm, while on the vertical the IMD 3rd
                                order
                                > values in dBm. From there you can calculate the IP3.
                                > One of the interesting measurements done by I4SBX is the finding
                                that
                                > for input signal over +5dBm the curves do not respond anymore to
                                the
                                > 3rd order but get steeper. This maybe due to the cores material
                                (????)
                                > but same risults are for grade #61; also a similar reaction is
                                obtained
                                > using toroids as core.
                                >
                                > Hope to have clarified your questions.
                                >
                                > Many friends have applied H-Mode Mixer replacement to commercial
                                > equipment with results varying from very large improvement to not
                                so
                                > high as expected. Generally this latter problems is associated with
                                > phase noise of PLL and LOs.
                                > A TR7 was modified and the vy noisy PLL forced the owner to replace
                                it
                                > with a AD9951 DDS from I0CG.
                                > A 1st Mixer mod on an IC706 risulted in an IP3 improvement of
                                around
                                > 15dB while replacing the 1st LO with a Xtal Oscillator the
                                improvement
                                > was nearly as high as the H-Mode Mixer IP3, something around 30dB.
                                > On the K2 from +15dBm (SBL1 with LO +7dBm)it went to +27dBm with
                                0dBm
                                > LO, taking into account the 2t h-mode mixer was followed by a 2xtal
                                > roofing filter so not a proper termination.
                                >
                                > I believe the best is to do your own experimenting with the H-Mode
                                > Mixer without listening too much to I7SWX ...hi
                                >
                                > 73
                                >
                                > Gian
                                > I7SWX
                                >


                              • Giancarlo
                                ... you ... order ... loss of ... Hi Tom, that s right. BTW average conversion loss of 2T H-Mode Mixer is around -5dB or less.
                                Message 15 of 25 , May 1, 2007
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                                  --- In softrock40@yahoogroups.com, "tom_iphi" <iphi@...> wrote:
                                  >
                                  > P.S.
                                  >
                                  > > The plot is simple ... hi... well in the bottom horizontal line
                                  you
                                  > > have the input power in dBm, while on the vertical the IMD 3rd
                                  order
                                  > > values in dBm. From there you can calculate the IP3.
                                  >
                                  > From that I can only calculate the IP3 if I know the conversion
                                  loss of
                                  > the mixer.
                                  > Example:
                                  > Say 10dBm input power, 6dB conversion loss
                                  > => 4dBm output power
                                  > IMD3 at -50dBm
                                  > => IMD3 at -54dBc on output
                                  > => Input IP3 = 10dBm +54/2dBm = 37dBm
                                  >
                                  > correct?
                                  >
                                  > Tom DG8SAQ
                                  >

                                  Hi Tom,

                                  that's right. BTW average conversion loss of 2T H-Mode Mixer is
                                  around -5dB or less. <there is a configuration that may increase CL
                                  up to < -7dBm with generally an increase in IP3.

                                  "Voices" are saying that the H-Mode Mixer has been integrated in a
                                  new military receiver ... certainly the G3SBI 3 transformers
                                  version ... imagine the military winding the I7SWX special
                                  transformer ... it will never work ...hi !

                                  73

                                  Gian
                                  I7SWX
                                • FRANCIS CARCIA
                                  I have an old handbook that has 4 tubes configured as an h mode mixer to generate DSB. sorry a bit before FETS and switches. fc ... you ... order ... loss of
                                  Message 16 of 25 , May 1, 2007
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                                    I have an old handbook that has 4 tubes configured as an h mode mixer to generate DSB.
                                    sorry a bit before FETS and switches. fc

                                    Giancarlo <i7swx@...> wrote:
                                    --- In softrock40@yahoogro ups.com, "tom_iphi" <iphi@...> wrote:
                                    >
                                    > P.S.
                                    >
                                    > > The plot is simple ... hi... well in the bottom horizontal line
                                    you
                                    > > have the input power in dBm, while on the vertical the IMD 3rd
                                    order
                                    > > values in dBm. From there you can calculate the IP3.
                                    >
                                    > From that I can only calculate the IP3 if I know the conversion
                                    loss of
                                    > the mixer.
                                    > Example:
                                    > Say 10dBm input power, 6dB conversion loss
                                    > => 4dBm output power
                                    > IMD3 at -50dBm
                                    > => IMD3 at -54dBc on output
                                    > => Input IP3 = 10dBm +54/2dBm = 37dBm
                                    >
                                    > correct?
                                    >
                                    > Tom DG8SAQ
                                    >

                                    Hi Tom,

                                    that's right. BTW average conversion loss of 2T H-Mode Mixer is
                                    around -5dB or less. <there is a configuration that may increase CL
                                    up to < -7dBm with generally an increase in IP3.

                                    "Voices" are saying that the H-Mode Mixer has been integrated in a
                                    new military receiver ... certainly the G3SBI 3 transformers
                                    version ... imagine the military winding the I7SWX special
                                    transformer ... it will never work ...hi !

                                    73

                                    Gian
                                    I7SWX


                                  • Giancarlo
                                    ... mixer to generate DSB. ... Hi Francis, thanks for your note. I have not seen such circuit and it would be interesting to see it. My feeling is that such
                                    Message 17 of 25 , May 2, 2007
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                                      --- In softrock40@yahoogroups.com, FRANCIS CARCIA <carcia@...> wrote:
                                      >
                                      > I have an old handbook that has 4 tubes configured as an h mode
                                      mixer to generate DSB.
                                      > sorry a bit before FETS and switches. fc
                                      >

                                      Hi Francis,

                                      thanks for your note. I have not seen such circuit and it would be
                                      interesting to see it.

                                      My feeling is that such circuit could be similar to the original
                                      mixer developed by Oxner ... a guess.
                                      The H-Mode Mixer was developed by G3SBI, modifying the Oxner design
                                      in such a way that the LO signals do not modulate the RF one. This is
                                      done taking the transformer windings to ground. My contributions were
                                      only the use of Fast Bus Switches like FST3125 and the like, this
                                      time in 1998, and then the simplified version using two transformers.

                                      73

                                      Gian
                                      I7SWX
                                    • FRANCIS CARCIA
                                      Hi Gian, Look at page 338 and 339 of the Radio Handbook by Bill Orr. addition fifteen 1959 and you will see the H mode mixer and four phase switch (tubes) used
                                      Message 18 of 25 , May 2, 2007
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                                        Hi Gian,
                                        Look at page 338 and 339 of the Radio Handbook by Bill Orr. addition fifteen 1959
                                        and you will see the H mode mixer and four phase switch (tubes) used to generate SSB.
                                        No Oxner never thought of referencing the FETs to ground. He always did a ring or single balanced mixer. I have his app notes.
                                        The solid state H mode mixer is a very good idea but it isn't new. G3SBI did a good job on this mixer and the performance is hard to beat!  frank wa1gfz

                                        Giancarlo <i7swx@...> wrote:
                                        --- In softrock40@yahoogro ups.com, FRANCIS CARCIA <carcia@...> wrote:
                                        >
                                        > I have an old handbook that has 4 tubes configured as an h mode
                                        mixer to generate DSB.
                                        > sorry a bit before FETS and switches. fc
                                        >

                                        Hi Francis,

                                        thanks for your note. I have not seen such circuit and it would be
                                        interesting to see it.

                                        My feeling is that such circuit could be similar to the original
                                        mixer developed by Oxner ... a guess.
                                        The H-Mode Mixer was developed by G3SBI, modifying the Oxner design
                                        in such a way that the LO signals do not modulate the RF one. This is
                                        done taking the transformer windings to ground. My contributions were
                                        only the use of Fast Bus Switches like FST3125 and the like, this
                                        time in 1998, and then the simplified version using two transformers.

                                        73

                                        Gian
                                        I7SWX


                                      • Giancarlo
                                        ... addition fifteen 1959 ... used to generate SSB. ... always did a ring or single balanced mixer. I have his app notes. ... new. G3SBI did a good job on this
                                        Message 19 of 25 , May 2, 2007
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                                          --- In softrock40@yahoogroups.com, FRANCIS CARCIA <carcia@...> wrote:
                                          >
                                          > Hi Gian,
                                          > Look at page 338 and 339 of the Radio Handbook by Bill Orr.
                                          addition fifteen 1959
                                          > and you will see the H mode mixer and four phase switch (tubes)
                                          used to generate SSB.
                                          > No Oxner never thought of referencing the FETs to ground. He
                                          always did a ring or single balanced mixer. I have his app notes.
                                          > The solid state H mode mixer is a very good idea but it isn't
                                          new. G3SBI did a good job on this mixer and the performance is hard
                                          to beat! frank wa1gfz

                                          HI Frank,

                                          thanks for the info .... Bill Orr is in QRT somewhere ... but where
                                          do you think am I going to recuperate hi Radio Handbook date 1959 on
                                          this side of the pond? I am sorry I am not travelling anymore to W-
                                          land so I connot visit any library.

                                          It would be interesting if you could copy the two pages and upload
                                          the file in files.

                                          Thanks and 73

                                          Gian
                                          I7SWX


                                          >
                                          > Giancarlo <i7swx@...> wrote:
                                          > --- In softrock40@yahoogroups.com, FRANCIS CARCIA
                                          <carcia@> wrote:
                                          > >
                                          > > I have an old handbook that has 4 tubes configured as an h mode
                                          > mixer to generate DSB.
                                          > > sorry a bit before FETS and switches. fc
                                          > >
                                          >
                                          > Hi Francis,
                                          >
                                          > thanks for your note. I have not seen such circuit and it would be
                                          > interesting to see it.
                                          >
                                          > My feeling is that such circuit could be similar to the original
                                          > mixer developed by Oxner ... a guess.
                                          > The H-Mode Mixer was developed by G3SBI, modifying the Oxner design
                                          > in such a way that the LO signals do not modulate the RF one. This
                                          is
                                          > done taking the transformer windings to ground. My contributions
                                          were
                                          > only the use of Fast Bus Switches like FST3125 and the like, this
                                          > time in 1998, and then the simplified version using two
                                          transformers.
                                          >
                                          > 73
                                          >
                                          > Gian
                                          > I7SWX
                                          >
                                        • FRANCIS CARCIA
                                          http://www.tech-systems-labs.com/books.htm Hi Gian, go to the link above and down load it for free. frank ... addition fifteen 1959 ... used to generate SSB.
                                          Message 20 of 25 , May 2, 2007
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                                            Hi Gian,
                                            go to the link above and down load it for free. frank

                                            Giancarlo <i7swx@...> wrote:
                                            --- In softrock40@yahoogro ups.com, FRANCIS CARCIA <carcia@...> wrote:
                                            >
                                            > Hi Gian,
                                            > Look at page 338 and 339 of the Radio Handbook by Bill Orr.
                                            addition fifteen 1959
                                            > and you will see the H mode mixer and four phase switch (tubes)
                                            used to generate SSB.
                                            > No Oxner never thought of referencing the FETs to ground. He
                                            always did a ring or single balanced mixer. I have his app notes.
                                            > The solid state H mode mixer is a very good idea but it isn't
                                            new. G3SBI did a good job on this mixer and the performance is hard
                                            to beat! frank wa1gfz

                                            HI Frank,

                                            thanks for the info .... Bill Orr is in QRT somewhere ... but where
                                            do you think am I going to recuperate hi Radio Handbook date 1959 on
                                            this side of the pond? I am sorry I am not travelling anymore to W-
                                            land so I connot visit any library.

                                            It would be interesting if you could copy the two pages and upload
                                            the file in files.

                                            Thanks and 73

                                            Gian
                                            I7SWX

                                            >
                                            > Giancarlo <i7swx@...> wrote:
                                            > --- In softrock40@yahoogro ups.com, FRANCIS CARCIA
                                            <carcia@> wrote:
                                            > >
                                            > > I have an old handbook that has 4 tubes configured as an h mode
                                            > mixer to generate DSB.
                                            > > sorry a bit before FETS and switches. fc
                                            > >
                                            >
                                            > Hi Francis,
                                            >
                                            > thanks for your note. I have not seen such circuit and it would be
                                            > interesting to see it.
                                            >
                                            > My feeling is that such circuit could be similar to the original
                                            > mixer developed by Oxner ... a guess.
                                            > The H-Mode Mixer was developed by G3SBI, modifying the Oxner design
                                            > in such a way that the LO signals do not modulate the RF one. This
                                            is
                                            > done taking the transformer windings to ground. My contributions
                                            were
                                            > only the use of Fast Bus Switches like FST3125 and the like, this
                                            > time in 1998, and then the simplified version using two
                                            transformers.
                                            >
                                            > 73
                                            >
                                            > Gian
                                            > I7SWX
                                            >


                                          • Lawrence
                                            ... It just happens that I have a copy of that edition of the handbook. I will scan those pages for you. 73, Lawrence GJ3RAX
                                            Message 21 of 25 , May 2, 2007
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                                              > Giancarlo wrote:
                                              >
                                              > thanks for the info .... Bill Orr is in QRT somewhere ...
                                              > but where
                                              > do you think am I going to recuperate hi Radio Handbook
                                              > date 1959 on
                                              > this side of the pond? I am sorry I am not travelling
                                              > anymore to W-
                                              > land so I connot visit any library.

                                              It just happens that I have a copy of that edition of the
                                              handbook. I will scan those pages for you.

                                              73, Lawrence GJ3RAX
                                            • Giancarlo
                                              Hi Frank, thanks for the dowloading address. I have found the ARRL 1959 edition not Bill Orr Handbook. 73 Gian I7SWX ... on ... be ... design ... This
                                              Message 22 of 25 , May 3, 2007
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                                                Hi Frank,

                                                thanks for the dowloading address. I have found the ARRL 1959 edition
                                                not Bill Orr Handbook.

                                                73

                                                Gian
                                                I7SWX

                                                --- In softrock40@yahoogroups.com, FRANCIS CARCIA <carcia@...> wrote:
                                                >
                                                > http://www.tech-systems-labs.com/books.htm
                                                >
                                                > Hi Gian,
                                                > go to the link above and down load it for free. frank
                                                >
                                                > Giancarlo <i7swx@...> wrote:
                                                > --- In softrock40@yahoogroups.com, FRANCIS CARCIA
                                                <carcia@> wrote:
                                                > >
                                                > > Hi Gian,
                                                > > Look at page 338 and 339 of the Radio Handbook by Bill Orr.
                                                > addition fifteen 1959
                                                > > and you will see the H mode mixer and four phase switch (tubes)
                                                > used to generate SSB.
                                                > > No Oxner never thought of referencing the FETs to ground. He
                                                > always did a ring or single balanced mixer. I have his app notes.
                                                > > The solid state H mode mixer is a very good idea but it isn't
                                                > new. G3SBI did a good job on this mixer and the performance is hard
                                                > to beat! frank wa1gfz
                                                >
                                                > HI Frank,
                                                >
                                                > thanks for the info .... Bill Orr is in QRT somewhere ... but where
                                                > do you think am I going to recuperate hi Radio Handbook date 1959
                                                on
                                                > this side of the pond? I am sorry I am not travelling anymore to W-
                                                > land so I connot visit any library.
                                                >
                                                > It would be interesting if you could copy the two pages and upload
                                                > the file in files.
                                                >
                                                > Thanks and 73
                                                >
                                                > Gian
                                                > I7SWX
                                                >
                                                > >
                                                > > Giancarlo <i7swx@> wrote:
                                                > > --- In softrock40@yahoogroups.com, FRANCIS CARCIA
                                                > <carcia@> wrote:
                                                > > >
                                                > > > I have an old handbook that has 4 tubes configured as an h mode
                                                > > mixer to generate DSB.
                                                > > > sorry a bit before FETS and switches. fc
                                                > > >
                                                > >
                                                > > Hi Francis,
                                                > >
                                                > > thanks for your note. I have not seen such circuit and it would
                                                be
                                                > > interesting to see it.
                                                > >
                                                > > My feeling is that such circuit could be similar to the original
                                                > > mixer developed by Oxner ... a guess.
                                                > > The H-Mode Mixer was developed by G3SBI, modifying the Oxner
                                                design
                                                > > in such a way that the LO signals do not modulate the RF one.
                                                This
                                                > is
                                                > > done taking the transformer windings to ground. My contributions
                                                > were
                                                > > only the use of Fast Bus Switches like FST3125 and the like, this
                                                > > time in 1998, and then the simplified version using two
                                                > transformers.
                                                > >
                                                > > 73
                                                > >
                                                > > Gian
                                                > > I7SWX
                                                > >
                                                >
                                              • Giancarlo
                                                ... Hi Lawrence, thanks if it is not a problem. Was your long time ago (1996?) trip to VE good? 73 Gian I7SWX
                                                Message 23 of 25 , May 3, 2007
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                                                  --- In softrock40@yahoogroups.com, "Lawrence" <lawrence@...> wrote:
                                                  >
                                                  > > Giancarlo wrote:
                                                  > >
                                                  > > thanks for the info .... Bill Orr is in QRT somewhere ...
                                                  > > but where
                                                  > > do you think am I going to recuperate hi Radio Handbook
                                                  > > date 1959 on
                                                  > > this side of the pond? I am sorry I am not travelling
                                                  > > anymore to W-
                                                  > > land so I connot visit any library.
                                                  >
                                                  > It just happens that I have a copy of that edition of the
                                                  > handbook. I will scan those pages for you.
                                                  >
                                                  > 73, Lawrence GJ3RAX
                                                  >
                                                  Hi Lawrence,

                                                  thanks if it is not a problem.

                                                  Was your long time ago (1996?) trip to VE good?

                                                  73

                                                  Gian
                                                  I7SWX
                                                • FRANCIS CARCIA
                                                  Gian, You misread it. Check again. it was a bigger seller than the ARRL handbook Back then the West coast guys were the QRO kings.......The Bible for them
                                                  Message 24 of 25 , May 3, 2007
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                                                    Gian,
                                                    You misread it. Check again. "it was a bigger seller than the ARRL handbook"
                                                    Back then the West coast guys were the QRO kings.......The Bible for them was written by Bill Orr. It was often called the West coast Handbook. fc

                                                    Giancarlo <i7swx@...> wrote:
                                                    Hi Frank,

                                                    thanks for the dowloading address. I have found the ARRL 1959 edition
                                                    not Bill Orr Handbook.

                                                    73

                                                    Gian
                                                    I7SWX

                                                    --- In softrock40@yahoogro ups.com, FRANCIS CARCIA <carcia@...> wrote:
                                                    >
                                                    > http://www.tech- systems-labs. com/books. htm
                                                    >
                                                    > Hi Gian,
                                                    > go to the link above and down load it for free. frank
                                                    >
                                                    > Giancarlo <i7swx@...> wrote:
                                                    > --- In softrock40@yahoogro ups.com, FRANCIS CARCIA
                                                    <carcia@> wrote:
                                                    > >
                                                    > > Hi Gian,
                                                    > > Look at page 338 and 339 of the Radio Handbook by Bill Orr.
                                                    > addition fifteen 1959
                                                    > > and you will see the H mode mixer and four phase switch (tubes)
                                                    > used to generate SSB.
                                                    > > No Oxner never thought of referencing the FETs to ground. He
                                                    > always did a ring or single balanced mixer. I have his app notes.
                                                    > > The solid state H mode mixer is a very good idea but it isn't
                                                    > new. G3SBI did a good job on this mixer and the performance is hard
                                                    > to beat! frank wa1gfz
                                                    >
                                                    > HI Frank,
                                                    >
                                                    > thanks for the info .... Bill Orr is in QRT somewhere ... but where
                                                    > do you think am I going to recuperate hi Radio Handbook date 1959
                                                    on
                                                    > this side of the pond? I am sorry I am not travelling anymore to W-
                                                    > land so I connot visit any library.
                                                    >
                                                    > It would be interesting if you could copy the two pages and upload
                                                    > the file in files.
                                                    >
                                                    > Thanks and 73
                                                    >
                                                    > Gian
                                                    > I7SWX
                                                    >
                                                    > >
                                                    > > Giancarlo <i7swx@> wrote:
                                                    > > --- In softrock40@yahoogro ups.com, FRANCIS CARCIA
                                                    > <carcia@> wrote:
                                                    > > >
                                                    > > > I have an old handbook that has 4 tubes configured as an h mode
                                                    > > mixer to generate DSB.
                                                    > > > sorry a bit before FETS and switches. fc
                                                    > > >
                                                    > >
                                                    > > Hi Francis,
                                                    > >
                                                    > > thanks for your note. I have not seen such circuit and it would
                                                    be
                                                    > > interesting to see it.
                                                    > >
                                                    > > My feeling is that such circuit could be similar to the original
                                                    > > mixer developed by Oxner ... a guess.
                                                    > > The H-Mode Mixer was developed by G3SBI, modifying the Oxner
                                                    design
                                                    > > in such a way that the LO signals do not modulate the RF one.
                                                    This
                                                    > is
                                                    > > done taking the transformer windings to ground. My contributions
                                                    > were
                                                    > > only the use of Fast Bus Switches like FST3125 and the like, this
                                                    > > time in 1998, and then the simplified version using two
                                                    > transformers.
                                                    > >
                                                    > > 73
                                                    > >
                                                    > > Gian
                                                    > > I7SWX
                                                    > >
                                                    >


                                                  • Giancarlo
                                                    ... ARRL handbook ... for them was written by Bill Orr. It was often called the West coast Handbook. fc ... edition ... Hi Frank, thanks... I found the book.
                                                    Message 25 of 25 , May 4, 2007
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                                                      --- In softrock40@yahoogroups.com, FRANCIS CARCIA <carcia@...> wrote:
                                                      >
                                                      > Gian,
                                                      > You misread it. Check again. "it was a bigger seller than the
                                                      ARRL handbook"
                                                      > Back then the West coast guys were the QRO kings.......The Bible
                                                      for them was written by Bill Orr. It was often called the West coast
                                                      Handbook. fc
                                                      >
                                                      > Giancarlo <i7swx@...> wrote:
                                                      > Hi Frank,
                                                      >
                                                      > thanks for the dowloading address. I have found the ARRL 1959
                                                      edition
                                                      > not Bill Orr Handbook.
                                                      >
                                                      > 73
                                                      >
                                                      > Gian
                                                      > I7SWX
                                                      >
                                                      >

                                                      Hi Frank,

                                                      thanks... I found the book.

                                                      73
                                                      Gian
                                                      I7SWX
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