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Galvanic Isolator

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  • stephen_qrp
    Hello These two items were recently drawn to my attention, does anybody have hands on experience of either or perhaps an informed opinion. 10KHz to 60MHz
    Message 1 of 17 , Sep 1, 2012
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      Hello

      These two items were recently drawn to my attention, does anybody have hands on experience of either or perhaps
      an informed opinion.

      10KHz to 60MHz Antenna Galvanic Isolator System for SDR radios

      USB Galvanic Digital Isolator for SDR radios

      http://www.herostechnology.co.uk/pages/RF_Filters/filters.html#DISO

      Regards to all

      Stephen

       
    • andrea montefusco
      ... Stephen, as previously mentioned on list (search for Perseus usb isolator ), this kind of USB isolator is not suitable for Perseus, and neither for
      Message 2 of 17 , Sep 1, 2012
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        On Sat, Sep 1, 2012 at 10:00 AM, stephen_qrp <stephen_qrp@...> wrote:

        Stephen,
        as previously mentioned on list (search for "Perseus usb isolator"), this kind of USB isolator is not suitable for Perseus, and neither for high-end DDC/QSD radios, because it doesn't support high speed data rate.

        In any case, I own this one (a kit, so it is cheaper):

        http://www.circuitsathome.com/products-page/usb-interfaces/adum4160-usb-isolator-board-bare-pcb-and-kits/

        I found it quite useful with the old versions of Softrock and PMSDR, together with a galvanic isolator on antenna side, in order  to delete the peak, and provide them clean power (instead of derive it from USB).
        The most recent versions of Softrock come already equipped with USB isolators.

        For what concern the antenna isolators, if you search into the list archive, Alberto I2PHD posted his single toroid design, cheap and effective.

          *am*

        --
        Andrea Montefusco IW0HDV

      • Alberto I2PHD
        ... It costs me very little to post again the photo of that simple galvanic isolator. Just make sure to use a high permeability ferrite, and maybe increase the
        Message 3 of 17 , Sep 1, 2012
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          On 9/1/2012 10:41 AM, andrea montefusco wrote:

          For what concern the antenna isolators, if you search into the list archive,
          Alberto I2PHD posted his single toroid design, cheap and effective.

          It costs me very little to post again the photo of that simple galvanic isolator.
          Just make sure to use a high permeability ferrite, and maybe increase the
          number of turns.  8 bifilar turns would be quite adequate.

          https://dl.dropbox.com/u/15089947/galvanic.jpg

          --
          73 Alberto I2PHD
        • maurits
          Are FT 114-43 also good ? have it still lying in the shack Thanks in advance 73, Maurits
          Message 4 of 17 , Sep 1, 2012
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             Are FT  114-43  also  good ?  have it still lying in the shack
             Thanks in advance
             73,
             Maurits
             

            On 9/1/2012 10:41 AM, andrea montefusco wrote:

            For what concern the antenna isolators, if you search into the list archive,
            Alberto I2PHD posted his single toroid design, cheap and effective.

            It costs me very little to post again the photo of that simple galvanic isolator.
            Just make sure to use a high permeability ferrite, and maybe increase the
            number of turns.  8 bifilar turns would be quite adequate.

            https://dl.dropbox.com/u/15089947/galvanic.jpg

            --
            73 Alberto I2PHD

        • Roelof Bakker
          Hello Maurits, The FT114-43 is fine. 10 turns is OK from 500 kHz and up. 73, Roelof
          Message 5 of 17 , Sep 1, 2012
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            Hello Maurits,

            The FT114-43 is fine.
            10 turns is OK from 500 kHz and up.

            73,
            Roelof
          • Mark D Mobile
            The USB Isolator appears to provide 100 milliamps current to the peripheral device; that’s far less than what the Perseus calls for (700 ma). Mark
            Message 6 of 17 , Sep 1, 2012
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              The USB Isolator appears to provide 100 milliamps current to the peripheral device; that’s far less than what the Perseus calls for (700 ma).
               
              Mark Durenberger
              On the Road
               
              Sent: Saturday, September 01, 2012 3:00 AM
              Subject: [perseus_SDR] Galvanic Isolator
               
               

              Hello

              These two items were recently drawn to my attention, does anybody have hands on experience of either or perhaps
              an informed opinion.

              10KHz to 60MHz Antenna Galvanic Isolator System for SDR radios

              USB Galvanic Digital Isolator for SDR radios

              http://www.herostechnology.co.uk/pages/RF_Filters/filters.html#DISO

              Regards to all

              Stephen

               

            • maurits
              Many thanks , Roelof Sunny days from Belgium 73, Maurits
              Message 7 of 17 , Sep 1, 2012
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                Many thanks , Roelof
                Sunny days from Belgium
                73,
                Maurits
                > Hello Maurits,
                >
                > The FT114-43 is fine.
                > 10 turns is OK from 500 kHz and up.
                >
                > 73,
                > Roelof
                >
                >
                > ------------------------------------
                >
                > Yahoo! Groups Links
                >
                >
                >
                >
              • Alberto I2PHD
                ... Roelof is right, the -43 material has less permeability of the -77 mix I used, but it can be used, unless you want to dig deep in the low LF realm.... For
                Message 8 of 17 , Sep 1, 2012
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                  On 9/1/2012 2:22 PM, Roelof Bakker wrote:
                  The FT114-43 is fine.
                  10 turns is OK from 500 kHz and up.

                  Roelof is right, the -43 material has less permeability of the -77 mix I used, but it
                  can be used, unless you want to dig deep in the low LF realm....
                  For example, a few German and UK amateurs are experimenting with the 8.97 kHz band.
                  For such low a frequency, you need the highest permeability material you can obtain,
                  like -77 or -J, and also increase the number of turns.

                  For the NDB band, probably the -43 ferrite would do, with 15 to 20 bifilar turns.

                  --
                  73 Alberto I2PHD
                • stephen_qrp
                  Hello Thank you for all the helpful and informative replies. Regards to all Stephen
                  Message 9 of 17 , Sep 2, 2012
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                    Hello

                    Thank you for all the helpful and informative replies.

                    Regards to all

                    Stephen
                  • Huw
                    There is no need to galvanicaly isolate the Perseus, just isolate the lowest frequency of interest. The simplest way of doing this is to have the antenna lead
                    Message 10 of 17 , Sep 2, 2012
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                      There is no need to galvanicaly isolate the Perseus, just isolate the lowest frequency of interest. The simplest way of doing this is to have the antenna lead go round a ferrite a few times, the ferrite isolates AC whereas the coax wound upon it transmits the RF without hinderence. Unlike transformers this can use an 'EMC' ferrite (one with loss) without causing problems. To make it easy thin coax is a good idea, I use some 50 ohm PTFE stuff that is 3.5mm diameter.

                      Huw
                      G7EBP


                      --- In perseus_SDR@yahoogroups.com, "stephen_qrp" <stephen_qrp@...> wrote:
                      >
                      > Hello
                      >
                      > Thank you for all the helpful and informative replies.
                      >
                      > Regards to all
                      >
                      > Stephen
                      >
                    • Huw
                      And the same can be done to the USB lead. I haven t found this nesessary though. Huw G7EBP
                      Message 11 of 17 , Sep 2, 2012
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                        And the same can be done to the USB lead. I haven't found this nesessary though.

                        Huw
                        G7EBP

                        --- In perseus_SDR@yahoogroups.com, "Huw" <huwfinney@...> wrote:
                        >
                        > There is no need to galvanicaly isolate the Perseus, just isolate the lowest frequency of interest. The simplest way of doing this is to have the antenna lead go round a ferrite a few times, the ferrite isolates AC whereas the coax wound upon it transmits the RF without hinderence. Unlike transformers this can use an 'EMC' ferrite (one with loss) without causing problems. To make it easy thin coax is a good idea, I use some 50 ohm PTFE stuff that is 3.5mm diameter.
                        >
                        > Huw
                        > G7EBP
                        >
                        >
                        > --- In perseus_SDR@yahoogroups.com, "stephen_qrp" <stephen_qrp@> wrote:
                        > >
                        > > Hello
                        > >
                        > > Thank you for all the helpful and informative replies.
                        > >
                        > > Regards to all
                        > >
                        > > Stephen
                        > >
                        >
                      • dl4raj
                        ... Maybe Stephen is looking for a device which prevents Perseus front end from being damaged by static voltage so that he hasn t to sell any more a Perseus
                        Message 12 of 17 , Sep 2, 2012
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                          > There is no need to galvanicaly isolate the Perseus,

                          Maybe Stephen is looking for a device which prevents Perseus'
                          front end from being damaged by static voltage so that he hasn't
                          to sell any more a Perseus with a smoked fronted on this list.

                          73
                          Clemens
                          DL4RAJ


                          --- In perseus_SDR@yahoogroups.com, "Huw" <huwfinney@...> wrote:
                          >
                          > There is no need to galvanicaly isolate the Perseus, just isolate the lowest frequency of interest. The simplest way of doing this is to have the antenna lead go round a ferrite a few times, the ferrite isolates AC whereas the coax wound upon it transmits the RF without hinderence. Unlike transformers this can use an 'EMC' ferrite (one with loss) without causing problems. To make it easy thin coax is a good idea, I use some 50 ohm PTFE stuff that is 3.5mm diameter.
                          >
                          > Huw
                          > G7EBP
                          >
                          >
                          > --- In perseus_SDR@yahoogroups.com, "stephen_qrp" <stephen_qrp@> wrote:
                          > >
                          > > Hello
                          > >
                          > > Thank you for all the helpful and informative replies.
                          > >
                          > > Regards to all
                          > >
                          > > Stephen
                          > >
                          >
                        • Huw
                          My ALA100 loop usues four diodes in series parellel to limit the volts, surly the same thin could be applied to the input of a Perseus. A transformer will
                          Message 13 of 17 , Sep 3, 2012
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                            My ALA100 loop usues four diodes in series parellel to limit the volts, surly the same thin could be applied to the input of a Perseus. A transformer will still pass a big voltage spike.

                            Huw
                            G7EBP

                            --- In perseus_SDR@yahoogroups.com, "dl4raj" <cpaul@...> wrote:
                            >
                            > > There is no need to galvanicaly isolate the Perseus,
                            >
                            > Maybe Stephen is looking for a device which prevents Perseus'
                            > front end from being damaged by static voltage so that he hasn't
                            > to sell any more a Perseus with a smoked fronted on this list.
                            >
                            > 73
                            > Clemens
                            > DL4RAJ
                            >
                            >
                            > --- In perseus_SDR@yahoogroups.com, "Huw" <huwfinney@> wrote:
                            > >
                            > > There is no need to galvanicaly isolate the Perseus, just isolate the lowest frequency of interest. The simplest way of doing this is to have the antenna lead go round a ferrite a few times, the ferrite isolates AC whereas the coax wound upon it transmits the RF without hinderence. Unlike transformers this can use an 'EMC' ferrite (one with loss) without causing problems. To make it easy thin coax is a good idea, I use some 50 ohm PTFE stuff that is 3.5mm diameter.
                            > >
                            > > Huw
                            > > G7EBP
                            > >
                            > >
                            > > --- In perseus_SDR@yahoogroups.com, "stephen_qrp" <stephen_qrp@> wrote:
                            > > >
                            > > > Hello
                            > > >
                            > > > Thank you for all the helpful and informative replies.
                            > > >
                            > > > Regards to all
                            > > >
                            > > > Stephen
                            > > >
                            > >
                            >
                          • Alberto I2PHD
                            ... Usually the purpose of a galvanic insulator is not that of protecting the radio from spikes, but rather that of preventing ground loops. -- /*73 Alberto
                            Message 14 of 17 , Sep 3, 2012
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                              On 9/3/2012 5:50 PM, Huw wrote:
                              My ALA100 loop usues four diodes in series parellel to limit the volts, surly the same thin 
                              could be applied to the input of a Perseus.  A transformer will still pass a big voltage spike.
                              Usually the purpose of a galvanic insulator is not that of protecting the radio from spikes,
                              but rather that of preventing ground loops.

                              --
                              73 Alberto I2PHD
                            • Huw
                              ... Yes I agree (hence the inductive isolation I suggested), but another poster said it may be for stopping the front end blowing up. Huw G7EBP
                              Message 15 of 17 , Sep 4, 2012
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                                > Usually the purpose of a galvanic insulator is not that of protecting the radio from spikes,
                                > but rather that of preventing ground loops.

                                Yes I agree (hence the inductive isolation I suggested), but another poster said it may be for stopping the front end blowing up.

                                Huw
                                G7EBP
                              • dl4raj
                                ... Huw, this was meant ironically to stephen-qrp who sold a perseus with a blown front end on this list without telling it was defective and a few weeks later
                                Message 16 of 17 , Sep 4, 2012
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                                  > Yes I agree (hence the inductive isolation I suggested), but another >poster said it may be for stopping the front end blowing up.

                                  Huw,

                                  this was meant ironically to stephen-qrp who sold
                                  a perseus with a blown front end on this list
                                  without telling it was defective and a few weeks later
                                  he offered another perseus for sale on the list.
                                  Hmmm?

                                  73
                                  Clemens

                                  --- In perseus_SDR@yahoogroups.com, "Huw" <huwfinney@...> wrote:
                                • Huw
                                  I was always told (by my mum) to take sarcasm and the like literally! Still, the technology works the same. Huw G7EBP
                                  Message 17 of 17 , Sep 5, 2012
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                                    I was always told (by my mum) to take sarcasm and the like literally!

                                    Still, the technology works the same.

                                    Huw
                                    G7EBP

                                    --- In perseus_SDR@yahoogroups.com, "dl4raj" <cpaul@...> wrote:
                                    >
                                    >
                                    > > Yes I agree (hence the inductive isolation I suggested), but another >poster said it may be for stopping the front end blowing up.
                                    >
                                    > Huw,
                                    >
                                    > this was meant ironically to stephen-qrp who sold
                                    > a perseus with a blown front end on this list
                                    > without telling it was defective and a few weeks later
                                    > he offered another perseus for sale on the list.
                                    > Hmmm?
                                    >
                                    > 73
                                    > Clemens
                                    >
                                    > --- In perseus_SDR@yahoogroups.com, "Huw" <huwfinney@> wrote:
                                    >
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