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RF Systems DX-One Pro MkII - Bi-Loop or not ?

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  • Fraser
    Hi All, A new question to ponder for the Group. I own an RF Systems DX-ONE Pro MKII and have tried to establish exactly what it is from the manufacturer....
    Message 1 of 16 , May 13, 2007
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      Hi All,

      A new question to ponder for the Group.

      I own an RF Systems DX-ONE Pro MKII and have tried to establish
      exactly what it is from the manufacturer.... they are staying
      silent :-(

      For those not familiar with the DX-One, it looks like a giant egg
      beater and if you believe the sales blurb it uses a high performance,
      very low noise overload resistant amplifier designed for the Dutch
      Military. Yet another mystery amplifier design !!!!

      I can vouch for the low noise element of the claim and it does
      perform very well at my rural UK location with good rejection of the
      house noise field.

      What still mystifies me is exactly what it is in terms of antenna
      type.

      It looks like the Bellini Tosi crossed loop DF antennas that I used
      to use on ships so I wondered if it is a crossed Bi-Loop to give
      omnidirectional covereage ? I suggested this to the manufacturer and
      received no response. It could be a compound monopole (folded up into
      the diamond shape) but the antenna is ground independant and requires
      only a safety ground for it's inbuilt ESD protection.

      I have gone as far as X-Raying the antenna "guts" but that did not
      reveal it's secret. there is a complex amplifier and several
      torroids. One appears to connect to the "loop arms" and another is at
      the output connector end of the amp.

      I should be grateful for any comment that this groups members may
      have on this antenna and it's design principle. Loop or Not Loop
      antenna, that is the question :-)

      I will post a picture of the DX-One in the photos area of this group
      for those who do not know of it.

      Fraser
    • Fraser
      Ref the DX-One and what is it I see that Universal sell it so there web site gives a good view of it. I will upload the PDF instructions and specs to the
      Message 2 of 16 , May 13, 2007
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        Ref the DX-One and "what is it"

        I see that Universal sell it so there web site gives a good view of it.

        I will upload the PDF instructions and specs to the files area for
        Group comment.

        Cheers

        Fraser
      • Fraser
        CORRECTION..... ... it. ... OOOOPs, I forgot the url for Universal ! Here are some urls related to the DX-1 and a review :-)
        Message 3 of 16 , May 13, 2007
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          CORRECTION.....

          --- In loopantennas@yahoogroups.com, "Fraser" <fraser.castle@...> wrote:
          >
          > Ref the DX-One and "what is it"
          >
          > I see that Universal sell it so there web site gives a good view of
          it.
          >
          > I will upload the PDF instructions and specs to the files area for
          > Group comment.
          >
          > Cheers
          >
          > Fraser


          OOOOPs, I forgot the url for Universal !

          Here are some urls related to the DX-1 and a review :-)


          http://www.universal-radio.com/catalog/sw_ant/1246.html

          http://www.rf-systems.nl/DX-one.html

          http://www.ratzer.at/DX_One.php

          and a review here....

          http://www.dxing.info/equipment/dx1pro.dx

          fraser
        • Paul Birke
          Dear Fraser had a look and look at the specs I think there is a big clue in the gain as it is only 10 dB to me that indicates a David Norton Noiseless
          Message 4 of 16 , May 13, 2007
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            Dear Fraser

            had a look and look at the specs

            I think there is a big clue in the gain as it is only 10 dB

            to me that indicates a David Norton Noiseless Amplifier and likely very close to what
            Dallas Lankford laid down in early 1990s

            the transformers here should be three

            [1] a centre-tapped input
            [2] the norton transformer
            [3] the output transformer

            one of these transformers is a toroid for sure ie the norton although this could be made as a binocular

            however either of [1] or [3] could be a mini-circuits plastic block

            just my take

            Paul V Birke PEng
            Guelph ON Canada



            ----- Original Message ----
            From: Fraser <fraser.castle@...>
            To: loopantennas@yahoogroups.com
            Sent: Sunday, May 13, 2007 7:56:16 AM
            Subject: [loopantennas] Re: RF Systems DX-One Pro MkII - Bi-Loop or not ?













            CORRECTION.. ...



            --- In loopantennas@ yahoogroups. com, "Fraser" <fraser.castle@ ...> wrote:

            >

            > Ref the DX-One and "what is it"

            >

            > I see that Universal sell it so there web site gives a good view of

            it.

            >

            > I will upload the PDF instructions and specs to the files area for

            > Group comment.

            >

            > Cheers

            >

            > Fraser



            OOOOPs, I forgot the url for Universal !



            Here are some urls related to the DX-1 and a review :-)



            http://www.universa l-radio.com/ catalog/sw_ ant/1246. html



            http://www.rf- systems.nl/ DX-one.html



            http://www.ratzer. at/DX_One. php



            and a review here....



            http://www.dxing. info/equipment/ dx1pro.dx



            fraser














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          • n2chi
            Hi Fraser, I hadn t thought polarization fading to be a big problem, although a real phenomenom, else every antenna since Marconi would have been egg- shaped
            Message 5 of 16 , May 13, 2007
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              Hi Fraser,
              I hadn't thought "polarization fading" to be a big problem, although a
              real phenomenom, else every antenna since Marconi would have been egg-
              shaped I'm thinking. I'm no expert, however. I'd guess the low noise
              comes from the quiet electronics and/or the loop aspect of the antenna,
              if it is a loop.
              Universal's write-up calls the antenna omnidirectional without regard to
              frequency, so that doesn't sound like a loop. The manufacturer's write
              up says their antenna is a "....combination of 2 loops, radials and a
              vertical receiving element." If the antenna is simply a vertical, I
              could imagine the loops performing a Yagi-like reflector function. But I
              don't think they would affect the polarization or phase. I guess that
              like most antennas, one has to A/B it with another to compare. Bring it
              over to my deck and we'll try it against my Wellbrook.
              Dave

              --- In loopantennas@yahoogroups.com, "Fraser" <fraser.castle@...> wrote:
              >
              > Hi All,
              >
              > A new question to ponder for the Group.
              >
              > I own an RF Systems DX-ONE Pro MKII and have tried to establish
              > exactly what it is from the manufacturer.... they are staying
              > silent :-(
              >
              > For those not familiar with the DX-One, it looks like a giant egg
              > beater and if you believe the sales blurb it uses a high performance,
              > very low noise overload resistant amplifier designed for the Dutch
              > Military. Yet another mystery amplifier design !!!!
              >
              > I can vouch for the low noise element of the claim and it does
              > perform very well at my rural UK location with good rejection of the
              > house noise field.
              >
              > What still mystifies me is exactly what it is in terms of antenna
              > type.
              >
              > It looks like the Bellini Tosi crossed loop DF antennas that I used
              > to use on ships so I wondered if it is a crossed Bi-Loop to give
              > omnidirectional covereage ? I suggested this to the manufacturer and
              > received no response. It could be a compound monopole (folded up into
              > the diamond shape) but the antenna is ground independant and requires
              > only a safety ground for it's inbuilt ESD protection.
              >
              > I have gone as far as X-Raying the antenna "guts" but that did not
              > reveal it's secret. there is a complex amplifier and several
              > torroids. One appears to connect to the "loop arms" and another is at
              > the output connector end of the amp.
              >
              > I should be grateful for any comment that this groups members may
              > have on this antenna and it's design principle. Loop or Not Loop
              > antenna, that is the question :-)
              >
              > I will post a picture of the DX-One in the photos area of this group
              > for those who do not know of it.
              >
              > Fraser
              >
            • n2chi
              Hi Fraser, I hadn t thought polarization fading to be a big problem, although a real phenomenom, else every antenna since Marconi would have been egg- shaped
              Message 6 of 16 , May 13, 2007
              • 0 Attachment
                Hi Fraser,
                I hadn't thought "polarization fading" to be a big problem, although a
                real phenomenom, else every antenna since Marconi would have been egg-
                shaped I'm thinking. I'm no expert, however. I'd guess the low noise
                comes from the quiet electronics and/or the loop aspect of the antenna,
                if it is a loop.
                Universal's write-up calls the antenna omnidirectional without regard to
                frequency, so that doesn't sound like a loop. The manufacturer's write
                up says their antenna is a "....combination of 2 loops, radials and a
                vertical receiving element." If the antenna is simply a vertical, I
                could imagine the loops performing a Yagi-like reflector function. But I
                don't think they would affect the polarization or phase. I guess that
                like most antennas, one has to A/B it with another to compare. Bring it
                over to my deck and we'll try it against my Wellbrook.
                Dave

                --- In loopantennas@yahoogroups.com, "Fraser" <fraser.castle@...> wrote:
                >
                > Hi All,
                >
                > A new question to ponder for the Group.
                >
                > I own an RF Systems DX-ONE Pro MKII and have tried to establish
                > exactly what it is from the manufacturer.... they are staying
                > silent :-(
                >
                > For those not familiar with the DX-One, it looks like a giant egg
                > beater and if you believe the sales blurb it uses a high performance,
                > very low noise overload resistant amplifier designed for the Dutch
                > Military. Yet another mystery amplifier design !!!!
                >
                > I can vouch for the low noise element of the claim and it does
                > perform very well at my rural UK location with good rejection of the
                > house noise field.
                >
                > What still mystifies me is exactly what it is in terms of antenna
                > type.
                >
                > It looks like the Bellini Tosi crossed loop DF antennas that I used
                > to use on ships so I wondered if it is a crossed Bi-Loop to give
                > omnidirectional covereage ? I suggested this to the manufacturer and
                > received no response. It could be a compound monopole (folded up into
                > the diamond shape) but the antenna is ground independant and requires
                > only a safety ground for it's inbuilt ESD protection.
                >
                > I have gone as far as X-Raying the antenna "guts" but that did not
                > reveal it's secret. there is a complex amplifier and several
                > torroids. One appears to connect to the "loop arms" and another is at
                > the output connector end of the amp.
                >
                > I should be grateful for any comment that this groups members may
                > have on this antenna and it's design principle. Loop or Not Loop
                > antenna, that is the question :-)
                >
                > I will post a picture of the DX-One in the photos area of this group
                > for those who do not know of it.
                >
                > Fraser
                >
              • Paul Birke
                Hi Fraser and All sorry scratch all that I just transmitted the 10 dB is the antenna alone LOL oh well Paul ... From: Paul Birke To:
                Message 7 of 16 , May 13, 2007
                • 0 Attachment
                  Hi Fraser and All

                  sorry scratch all that I just transmitted

                  the 10 dB is the antenna alone LOL

                  oh well

                  Paul

                  ----- Original Message ----
                  From: Paul Birke <nonlinear@...>
                  To: loopantennas@yahoogroups.com
                  Sent: Sunday, May 13, 2007 12:00:04 PM
                  Subject: Re: [loopantennas] Re: RF Systems DX-One Pro MkII - Bi-Loop or not ?













                  Dear Fraser



                  had a look and look at the specs



                  I think there is a big clue in the gain as it is only 10 dB



                  to me that indicates a David Norton Noiseless Amplifier and likely very close to what

                  Dallas Lankford laid down in early 1990s



                  the transformers here should be three



                  [1] a centre-tapped input

                  [2] the norton transformer

                  [3] the output transformer



                  one of these transformers is a toroid for sure ie the norton although this could be made as a binocular



                  however either of [1] or [3] could be a mini-circuits plastic block



                  just my take



                  Paul V Birke PEng

                  Guelph ON Canada





                  ----- Original Message ----

                  From: Fraser <fraser.castle@ virgin.net>

                  To: loopantennas@ yahoogroups. com

                  Sent: Sunday, May 13, 2007 7:56:16 AM

                  Subject: [loopantennas] Re: RF Systems DX-One Pro MkII - Bi-Loop or not ?



                  CORRECTION.. ...



                  --- In loopantennas@ yahoogroups. com, "Fraser" <fraser.castle@ ...> wrote:



                  >



                  > Ref the DX-One and "what is it"



                  >



                  > I see that Universal sell it so there web site gives a good view of



                  it.



                  >



                  > I will upload the PDF instructions and specs to the files area for



                  > Group comment.



                  >



                  > Cheers



                  >



                  > Fraser



                  OOOOPs, I forgot the url for Universal !



                  Here are some urls related to the DX-1 and a review :-)



                  http://www.universa l-radio.com/ catalog/sw_ ant/1246. html



                  http://www.rf- systems.nl/ DX-one.html



                  http://www.ratzer. at/DX_One. php



                  and a review here....



                  http://www.dxing. info/equipment/ dx1pro.dx



                  fraser



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                • Fraser
                  ... Hi Paul, Thanks for the input. The DX-One base unit has unusual calibrations on the attenuator. Instead of just showing the inserted attenuation it shows
                  Message 8 of 16 , May 13, 2007
                  • 0 Attachment
                    --- In loopantennas@yahoogroups.com, Paul Birke <nonlinear@...> wrote:
                    >
                    > Hi Fraser and All
                    >
                    > sorry scratch all that I just transmitted
                    >
                    > the 10 dB is the antenna alone LOL
                    >
                    > oh well
                    >
                    > Paul
                    >


                    Hi Paul,

                    Thanks for the input.

                    The DX-One base unit has unusual calibrations on the attenuator.
                    Instead of just showing the inserted attenuation it shows the system
                    gain.

                    The +10dB position is a straight through connection and is described
                    as +10dB because the antenna head is stated as having a gain of 10
                    dB. The 0dB position on the base unit is actually an insertion of
                    10dB attenuation. Theoreticaly in this position the input to the
                    receiver splitter is the same as the signal strength at the antenna
                    elements without any gain. This does not take account of feeder
                    losses though.

                    The base unit is a work of art. It's a very solid affair and contains
                    a low noise 28 Volt d.c regulated power supply, a calibrated stepped
                    attenuator, A MW filter and a high quality splitter. I bought a
                    couple of extra base units from Lowe(UK) last year for £20 each. They
                    are easy to convert to 12V output and work very well with any phantom
                    powered active antennas.

                    I will have to look out the X-Rays that I took of the Head unit
                    electronics as they may be of interest.

                    I note that the review that I refered to states that the DX-One
                    requires an excellent ground plane. I have the DX-One MKII and the
                    only groundplane requirement detailed in the instructions is for
                    static discharge purposes. The same is not true of my RFS DX-500
                    which requires an excellent groundplane to perform well.

                    Fraser
                  • Paul Birke
                    Dear Fraser In this case for direct feedthru I guess I un-tract my retraction (LOL again) smells like a Norton amp with this gain range ie 8 to 12 although
                    Message 9 of 16 , May 13, 2007
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                      Dear Fraser

                      In this case for direct feedthru I guess I un-tract my retraction (LOL again)

                      smells like a Norton amp with this gain range ie 8 to 12 although with higher turns can get to near 20 however 10 is a clue to the noiseless Norton amp in my opinion

                      (not to say other configurations will not end up something like this, such as a grounded base bipolar perhaps optimized for low noise)

                      xrays might prove interesting

                      best
                      Paul



                      ----- Original Message ----
                      From: Fraser <fraser.castle@...>
                      To: loopantennas@yahoogroups.com
                      Sent: Sunday, May 13, 2007 4:09:03 PM
                      Subject: [loopantennas] Re: RF Systems DX-One Pro MkII - Bi-Loop or not ?













                      --- In loopantennas@ yahoogroups. com, Paul Birke <nonlinear@. ..> wrote:

                      >

                      > Hi Fraser and All

                      >

                      > sorry scratch all that I just transmitted

                      >

                      > the 10 dB is the antenna alone LOL

                      >

                      > oh well

                      >

                      > Paul

                      >



                      Hi Paul,



                      Thanks for the input.



                      The DX-One base unit has unusual calibrations on the attenuator.

                      Instead of just showing the inserted attenuation it shows the system

                      gain.



                      The +10dB position is a straight through connection and is described

                      as +10dB because the antenna head is stated as having a gain of 10

                      dB. The 0dB position on the base unit is actually an insertion of

                      10dB attenuation. Theoreticaly in this position the input to the

                      receiver splitter is the same as the signal strength at the antenna

                      elements without any gain. This does not take account of feeder

                      losses though.



                      The base unit is a work of art. It's a very solid affair and contains

                      a low noise 28 Volt d.c regulated power supply, a calibrated stepped

                      attenuator, A MW filter and a high quality splitter. I bought a

                      couple of extra base units from Lowe(UK) last year for £20 each. They

                      are easy to convert to 12V output and work very well with any phantom

                      powered active antennas.



                      I will have to look out the X-Rays that I took of the Head unit

                      electronics as they may be of interest.



                      I note that the review that I refered to states that the DX-One

                      requires an excellent ground plane. I have the DX-One MKII and the

                      only groundplane requirement detailed in the instructions is for

                      static discharge purposes. The same is not true of my RFS DX-500

                      which requires an excellent groundplane to perform well.



                      Fraser














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                      [Non-text portions of this message have been removed]
                    • Steve Ratzlaff
                      Hi, I m familiar with the circuits used in the head end of the older DX-1 Pro, and the receiver coupler/supply. The head end is a basic high-impedance active
                      Message 10 of 16 , May 13, 2007
                      • 0 Attachment
                        Hi,
                        I'm familiar with the circuits used in the head end of the older DX-1 Pro,
                        and the receiver coupler/supply.
                        The head end is a basic high-impedance active whip antenna. The circuit is
                        an exact clone of the old Ralph Burhans circuit he published back in the
                        1980's, using 100% negative feedback. That would account for one of the
                        transformers noted by Fraser. The other transformer is very likely a
                        common-mode choke on the output. My older unit did not have that common-mode
                        choke; it only had the one feedback transformer. I'm guessing the "MK II"
                        means the common-mode choke addition was the only improvement from the
                        original DX-1 Pro.
                        The active power jfet device RF Systems is using has significant gate-source
                        capacitance, which acts to shunt signals to ground the higher you go in
                        frequency, and loss in sensitivity begins from about 12 MHz and up. They
                        devised the very elaborate "egg beater" cage whip antenna in an attempt to
                        improve the antenna capacitance, to offset the active device shunting
                        effect. The bit in the advertising about reducing polarization effects is
                        purely smoke and mirrors nonsense, and has no effect whatsoever on various
                        signal polarization being received better with that cage whip antenna. There
                        is no voltage gain for this active amplifier circuit, only overall loss from
                        input to output.
                        The receiver coupler's "+10dB" input position is also a piece of fiction.
                        That position directly couples the antenna's output through the various
                        other parts (switchable BCB filter and dual-output splitter) to the output
                        to the receiver. The other positions, "0" to "-40" are all switched
                        attenuators before going to the BCB filter and splitter, with the "0"
                        position being either -3 dB or -6 dB attenuation ( I forget which). The BCB
                        filter is not designed for the NA BCB frequency range but for Europe.
                        The active device is very similar to the Crystalonics CP650 power jfet
                        device that Dallas Lankford first discovered would work well in the old
                        Burhans active whip circuit--it too has significant gate-source input
                        capacitance. (This is the device the AMRAD active whip is using; they got
                        their circuit from Dallas Lankford, who was never given proper credit in the
                        article.)
                        I have been building and experimenting with active whip antennas for a
                        number of years now; I've tested just about every commercially available
                        antenna on the market, from either a hobby standpoint or from when my old
                        company was building active antennas as a Defense Contractor. The DX-1 Pro
                        is the only commercially available antenna that I've tried that I would
                        recommend, despite its increasing loss of sensitivity as you go up the HF
                        frequency range. However, it's very expensive for most hobbyists to even
                        consider purchasing one. And any active antenna performs only as well as the
                        local noise environment it's used in, and of course must be used externally
                        from any dwelling with AC power. The farther from AC power you can mount
                        such an antenna, either horizontal or vertical distance from AC power, the
                        better it can work without being limited by local AC noise.
                        73,
                        Steve
                        ----- Original Message -----
                        From: "Fraser" <fraser.castle@...>
                        To: <loopantennas@yahoogroups.com>
                        Sent: Sunday, May 13, 2007 4:29 AM
                        Subject: [loopantennas] RF Systems DX-One Pro MkII - Bi-Loop or not ?


                        > Hi All,
                        >
                        > A new question to ponder for the Group.
                        >
                        > I own an RF Systems DX-ONE Pro MKII and have tried to establish
                        > exactly what it is from the manufacturer.... they are staying
                        > silent :-(
                        >
                        > For those not familiar with the DX-One, it looks like a giant egg
                        > beater and if you believe the sales blurb it uses a high performance,
                        > very low noise overload resistant amplifier designed for the Dutch
                        > Military. Yet another mystery amplifier design !!!!
                        >
                        > I can vouch for the low noise element of the claim and it does
                        > perform very well at my rural UK location with good rejection of the
                        > house noise field.
                        >
                        > What still mystifies me is exactly what it is in terms of antenna
                        > type.
                        >
                        > It looks like the Bellini Tosi crossed loop DF antennas that I used
                        > to use on ships so I wondered if it is a crossed Bi-Loop to give
                        > omnidirectional covereage ? I suggested this to the manufacturer and
                        > received no response. It could be a compound monopole (folded up into
                        > the diamond shape) but the antenna is ground independant and requires
                        > only a safety ground for it's inbuilt ESD protection.
                        >
                        > I have gone as far as X-Raying the antenna "guts" but that did not
                        > reveal it's secret. there is a complex amplifier and several
                        > torroids. One appears to connect to the "loop arms" and another is at
                        > the output connector end of the amp.
                        >
                        > I should be grateful for any comment that this groups members may
                        > have on this antenna and it's design principle. Loop or Not Loop
                        > antenna, that is the question :-)
                        >
                        > I will post a picture of the DX-One in the photos area of this group
                        > for those who do not know of it.
                        >
                        > Fraser
                        >
                        >
                        >
                        > If you've got links, post them in the Links section!
                        > http://groups.yahoo.com/group/loopantennas/links
                        >
                        > Post files here. If the file comes from a website, please put it in the
                        > Links rather than uploading the file.
                        > http://groups.yahoo.com/group/loopantennas/files
                        >
                        > You can now view images at higher resolution in Photos. Upload JPG and GIF
                        > into Photos. Please convert BMP or TIF to JPG or GIF before uploading.
                        > http://ph.groups.yahoo.com/group/loopantennas/photos
                        >
                        > And please trim all this when replying!
                        > Yahoo! Groups Links
                        >
                        >
                        >
                      • Steve Ratzlaff
                        As a postscript to the RF Systems DX-1 Pro active whip antenna comments I made, WRTH did an extensive review of various active whip antennas perhaps 5 or more
                        Message 11 of 16 , May 13, 2007
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                          As a postscript to the RF Systems DX-1 Pro active whip antenna comments I
                          made, WRTH did an extensive review of various active whip antennas perhaps 5
                          or more years ago. The DX-1 Pro was clearly identified as an active whip
                          antenna then, and was one of the antennas reviewed--it had a good review
                          rating. The newer "MK II" apparently is a recent variation of that same
                          active whip antenna. Perhaps the addition of a common-mode choke on the
                          output of the whipamp is the only change, as I suggested in my previous
                          post.

                          73,
                          Steve
                        • Fraser
                          ... DX-1 Pro, ... circuit is ... in the ... (SNIPPED) Hi Steve, Many thanks for that superb description of the DX-1. You have made my day as I have been
                          Message 12 of 16 , May 14, 2007
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                            --- In loopantennas@yahoogroups.com, "Steve Ratzlaff"
                            <steveratz@...> wrote:
                            >
                            > Hi,
                            > I'm familiar with the circuits used in the head end of the older
                            DX-1 Pro,
                            > and the receiver coupler/supply.
                            > The head end is a basic high-impedance active whip antenna. The
                            circuit is
                            > an exact clone of the old Ralph Burhans circuit he published back
                            in the
                            > 1980's, using 100% negative feedback.
                            (SNIPPED)


                            Hi Steve,

                            Many thanks for that superb description of the DX-1. You have made
                            my day as I have been scratching my head about this antennas design
                            for ages.

                            When I X-Rayed the mast section it had four wires interconnecting
                            the various 'loop' arms but I couldn't be sure how they were
                            connected. They certainly are not all wired in parallel in the MKII.
                            I was wondering if they had wired the 'loop' arms in series to
                            effectively compress a long whip into a small space. This bit of the
                            design still eludes me.

                            As for the amplifier... your information is invaluable. The MKII
                            amplifier is stated as providing 10dB gain whereas the MKI was
                            spec'ed at 6dB gain. The issue of input capacitance is very
                            interesting indeed. I have some NOS Motorola high power jFETs (or
                            tFETS ?) that were used in some Watkins Johnson amplifiers that I
                            maintained. I suspect that these will also exhibit higher than
                            desirable input capacitance so I will re think using them in any
                            antenna designs that I build.

                            Thank you for your excellent help with this question Steve. It does,
                            however, lead me to wonder about RF Systems performance claims. RFS
                            make the MLB1 and this has caused much discussion both positive and
                            negative. I like their AA-150 that was built for the Lowe HF-150 but
                            it may be no better than any other active whip on the market. It is
                            well built though. The DX-10 is basically an AA-150 in a different
                            shell. As for the passive HF magnetic whips and some of their other
                            exotic designs, I am not sure that these are not just well
                            engineered 'snake oil' antennas. I own an RF Systems DX-500 which is
                            beautifully constructed and claims to work upto 500 MHz. I have
                            found that it needs an excellent groundplane for HF work and is
                            really just an RF probe (it has an extremely short active element).

                            Oh well.... it looks like the DX-1 is just an exotic & expensive
                            active whip pretending to be a loop then :-(

                            Thanks to everyone for their input on this topic. I'm off to start
                            saving for a Wellbrook ALA1530+.

                            Fraser
                          • ulrich_ruch
                            Hi Fraser just once more browsing thru DX-one threads...: apparently you are in possession of Xrays! Could you please forward copies to my email address
                            Message 13 of 16 , Dec 30, 2013
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                              Hi Fraser

                               

                              just once more browsing thru DX-one threads...: apparently you are in possession of Xrays! Could you please forward copies to my email address ulrich.ruch@.... My headamplifier has been laying around defective for more than one year, and all my queries at RFS remained unanswered. I would therefore  like to have it repaired by some local - but for this I need to know how to get access to the amplifier resp. how disassembly is made without causing any damage to the rest of the antenna stub.

                               

                              Looking forward with keen interest to Hearing from you.

                               

                              73s and happy New Year

                              Ulrich Ruch

                              Hinterester 13

                              CH 8184 Bachenbülach

                            • ihmeyers19
                              I had a DX-One (MK2) for about two years. It worked very well but my HOA made me take in down and I ended up selling it. 1) It is ABSOLUTELY an omni-direction
                              Message 14 of 16 , Jan 1, 2014
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                                I had a DX-One (MK2) for about two years.  It worked very well but my HOA made me take in down and I ended up selling it.

                                1) It is ABSOLUTELY an omni-direction vertical.

                                2)  It was the best vertical I had ever used and I had most of them.  I now have a DX Engineering active whip because it is lower profile.  I would say it has 80%+ of the performance of the DX-One at 25% of the price.  Where the DX-One REALLY excelled was in the LW band where reception was significantly better than with any other antenna I ever used.

                                3) I seem to recall that the developer (and President) of RF Systems died earlier this year.  My understanding was that the company was no longer in business though it seems Universal Radio still carries their products.

                                73, and Happy New Year,
                                Ian Meyers
                                Boynton Beach, Flroida
                              • johnnyc604
                                Ian, Did you by any chance have a Wellbrook 330S or 1530S in the past collection of antennas you could compare the RF Systems to? Thanks, John
                                Message 15 of 16 , Jan 2, 2014
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                                  Ian,

                                  Did you by any chance have a Wellbrook 330S or 1530S in the past collection of antennas you could compare the RF Systems to?

                                  Thanks,

                                  John

                                  --- In loopantennas@yahoogroups.com, <ihmeyers19@...> wrote:
                                  >
                                  > I had a DX-One (MK2) for about two years. It worked very well but my HOA made me take in down and I ended up selling it.
                                  >
                                  > 1) It is ABSOLUTELY an omni-direction vertical.
                                  >
                                  > 2) It was the best vertical I had ever used and I had most of them. I now have a DX Engineering active whip because it is lower profile. I would say it has 80%+ of the performance of the DX-One at 25% of the price. Where the DX-One REALLY excelled was in the LW band where reception was significantly better than with any other antenna I ever used.
                                  >
                                  > 3) I seem to recall that the developer (and President) of RF Systems died earlier this year. My understanding was that the company was no longer in business though it seems Universal Radio still carries their products.
                                  >
                                  > 73, and Happy New Year,
                                  > Ian Meyers
                                  > Boynton Beach, Flroida
                                  >
                                • ihmeyers19
                                  Unfortunately not John. I do have a Pixel Pro 1B now. No comparison, the DX-One was WAY better. In fact I think all in my DX Engineering Active Vertical is
                                  Message 16 of 16 , Jan 3, 2014
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                                    Unfortunately not John.  I do have a Pixel Pro 1B now.  No comparison, the DX-One was WAY better.  In fact I think all in my DX Engineering Active Vertical is better than the Pixel as well.

                                    Maybe I am just lucky because this is a pretty low noise QTH but here at least the only thing I get out of the Pixel is directionality and that's just on BCB.  The overall signal levels on the Pixel are a few db lower than the vertical on anything above say 3 MHZ.  Not awful / unreadable but lower than on the vertical and of course there is virtually zero directionality on skywave.

                                    I guess if you lived in a noisy environment a loop would be much more beneficial but it hasn't been here,  Perhaps a Wellbrook would be better but there seems to be no consensus on that.  Guy Atkins' tests point to the Wellbrook, Jack Smith's to the Pixel and both of those guys are knowledgeable, creditable sources so maybe its a QTH specific thing.



                                    JMHO.


                                    73,

                                    Ian

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