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Tamura MET-46 transformer sources?

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  • pond.james_pond
    Does anyone know of a UK supplier of these components with reasonable delivery charges? I flat refuse to pay the £12 delivery Mouser are asking for 2 £7.92
    Message 1 of 13 , Dec 9, 2010
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      Does anyone know of a UK supplier of these components with reasonable delivery charges? I flat refuse to pay the £12 delivery Mouser are asking for 2 £7.92 items.

      Thanks and 73.
    • Sid Boyce
      ... Tamura UK in Swindon only seem to stock power transformers. Both Mouser and Digikey will stitch you up for £12 shipping. At RS Components the Triad
      Message 2 of 13 , Dec 9, 2010
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        On 09/12/10 21:37, pond.james_pond wrote:
        > Does anyone know of a UK supplier of these components with reasonable
        > delivery charges? I flat refuse to pay the £12 delivery Mouser are
        > asking for 2 £7.92 items.
        >
        > Thanks and 73.
        >

        Tamura UK in Swindon only seem to stock power transformers. Both Mouser
        and Digikey will stitch you up for £12 shipping. At RS Components the
        Triad Magnetics SP-70 ones are £12.66 each (plus VAT??) shipped within
        10 working days, so there seems to be no reasonably priced ones
        available over here.
        73 ... Sid.
        --
        Sid Boyce ... Hamradio License G3VBV, Licensed Private Pilot
        Emeritus IBM/Amdahl Mainframes and Sun/Fujitsu Servers Tech Support
        Senior Staff Specialist, Cricket Coach
        Microsoft Windows Free Zone - Linux used for all Computing Tasks
      • g8voip
        Hi James, I wonder if you were planning to try and use those transformers in the I/Q lines? Looking at the data sheet, the only reference to bandwidth is 300Hz
        Message 3 of 13 , Dec 9, 2010
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          Hi James,

          I wonder if you were planning to try and use those transformers in the I/Q lines? Looking at the data sheet, the only reference to bandwidth is 300Hz to 3.5kHz, so probably pretty useless for SDR use.

          A better bet might be from Farnell, part number 1689035, OEP Oxford Electric Products A262A7E 600 ohm transformer, quoted spec 35Hz to 35kHz. Like all of these, not cheap £10.10 ex VAT each.

          A friend did bring his to show me, and I was surprised to see some improvement when fitting them to my SDR set up. Whether the small improvement is worth the expense is another matter.

          73, Bob G8VOI


          --- In softrock40@yahoogroups.com, Sid Boyce <sboyce@...> wrote:
          >
          > On 09/12/10 21:37, pond.james_pond wrote:
          > > Does anyone know of a UK supplier of these components with reasonable
          > > delivery charges? I flat refuse to pay the £12 delivery Mouser are
          > > asking for 2 £7.92 items.
          > >
          > > Thanks and 73.
          > >
          >
          > Tamura UK in Swindon only seem to stock power transformers. Both Mouser
          > and Digikey will stitch you up for £12 shipping. At RS Components the
          > Triad Magnetics SP-70 ones are £12.66 each (plus VAT??) shipped within
          > 10 working days, so there seems to be no reasonably priced ones
          > available over here.
          > 73 ... Sid.
          > --
          > Sid Boyce ... Hamradio License G3VBV, Licensed Private Pilot
          > Emeritus IBM/Amdahl Mainframes and Sun/Fujitsu Servers Tech Support
          > Senior Staff Specialist, Cricket Coach
          > Microsoft Windows Free Zone - Linux used for all Computing Tasks
          >
        • Alan
          ... From: g8voip Subject: [softrock40] Re: Tamura MET-46 transformer sources? ... I have tried a couple of transformer types. One the usual 600/600 modem,
          Message 4 of 13 , Dec 10, 2010
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            ----- Original Message -----
            From: "g8voip"
            Subject: [softrock40] Re: Tamura MET-46 transformer sources?


            >I wonder if you were planning to try and use those transformers in the I/Q
            >lines? Looking at the data sheet, the only reference to bandwidth is 300Hz
            >to 3.5kHz, so probably pretty useless for SDR use.
            > and I was surprised to see some improvement when fitting them to my SDR
            > set up. Whether the small improvement is worth the expense is another
            > matter.


            I have tried a couple of transformer types.
            One the usual 600/600 modem, the other Pico with a poorer LF like the one
            above.
            Both seemed to work satisfactorily within their limits but neither would
            allow decoding of DRM.

            73 Alan G4ZFQ
          • pond.james_pond
            Hi all, and thanks for the comments. Yes I intend to use these for IQ audio isolation. The frequency range stated on the Mouser website for these transformers
            Message 5 of 13 , Dec 10, 2010
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              Hi all, and thanks for the comments. Yes I intend to use these for IQ audio isolation. The frequency range stated on the Mouser website for these transformers is 300 Hz to 100 KHz (http://www.mouser.com/ProductDetail/Tamura/MET-46/?qs=BMSuqZ76GYQKF8a%252b2t3qoA%3D%3D), which differs from the spec' sheet. The response figures on the spec' sheet however are relative to +-1dB at 1 KHz, perhaps this is where the confusion arises. Anyone with further info'?

              --- In softrock40@yahoogroups.com, "g8voip" <g8voi.reeves59@...> wrote:
              >
              > Hi James,
              >
              > I wonder if you were planning to try and use those transformers in the I/Q lines? Looking at the data sheet, the only reference to bandwidth is 300Hz to 3.5kHz, so probably pretty useless for SDR use.
              >
              > A better bet might be from Farnell, part number 1689035, OEP Oxford Electric Products A262A7E 600 ohm transformer, quoted spec 35Hz to 35kHz. Like all of these, not cheap £10.10 ex VAT each.
              >
              > A friend did bring his to show me, and I was surprised to see some improvement when fitting them to my SDR set up. Whether the small improvement is worth the expense is another matter.
              >
              > 73, Bob G8VOI
              >
              >
              > --- In softrock40@yahoogroups.com, Sid Boyce <sboyce@> wrote:
              > >
              > > On 09/12/10 21:37, pond.james_pond wrote:
              > > > Does anyone know of a UK supplier of these components with reasonable
              > > > delivery charges? I flat refuse to pay the £12 delivery Mouser are
              > > > asking for 2 £7.92 items.
              > > >
              > > > Thanks and 73.
              > > >
              > >
              > > Tamura UK in Swindon only seem to stock power transformers. Both Mouser
              > > and Digikey will stitch you up for £12 shipping. At RS Components the
              > > Triad Magnetics SP-70 ones are £12.66 each (plus VAT??) shipped within
              > > 10 working days, so there seems to be no reasonably priced ones
              > > available over here.
              > > 73 ... Sid.
              > > --
              > > Sid Boyce ... Hamradio License G3VBV, Licensed Private Pilot
              > > Emeritus IBM/Amdahl Mainframes and Sun/Fujitsu Servers Tech Support
              > > Senior Staff Specialist, Cricket Coach
              > > Microsoft Windows Free Zone - Linux used for all Computing Tasks
              > >
              >
            • Alan
              ... From: pond.james_pond Subject: [softrock40] Re: Tamura MET-46 transformer sources? Hi all, and thanks for the comments. Yes I intend to use these for IQ
              Message 6 of 13 , Dec 10, 2010
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                ----- Original Message -----
                From: "pond.james_pond"
                Subject: [softrock40] Re: Tamura MET-46 transformer sources?


                Hi all, and thanks for the comments. Yes I intend to use these for IQ audio
                isolation. The frequency range stated on the Mouser website for these
                transformers is 300 Hz to 100 KHz >>. Anyone with further info'?


                <http://www.cliftonlaboratories.com/softrock_lite_6_2.htm> looks into it
                well. I think he says the response is better if impedances are higher.

                73 Alan G4ZFQ
              • g8voip
                Hi James, I would take any spec the seller provides with a pinch of salt! There is no mention of bandwidth at all on the manufacturers datasheet. The only
                Message 7 of 13 , Dec 10, 2010
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                  Hi James,

                  I would take any spec the seller provides with a pinch of salt!

                  There is no mention of bandwidth at all on the manufacturers datasheet. The only reference is to the flatness of the response over the limited range 300Hz to 3.5kHz being within 1dB.

                  Who knows what the variation is over a much wider range. Ultimately if you use two of them in the I/Q lines, the main importance is the matcing of the characteristics between two random samples over the whole spectrum.

                  The often quoted figures to achieve 60dB image rejection of needing the I/Q signals matched in gain to 0.01dB and phase to 0.1 degree sort of put things into perspective.

                  73, Bob G8VOI


                  --- In softrock40@yahoogroups.com, "pond.james_pond" <crusty@...> wrote:
                  >
                  > Hi all, and thanks for the comments. Yes I intend to use these for IQ audio isolation. The frequency range stated on the Mouser website for these transformers is 300 Hz to 100 KHz (http://www.mouser.com/ProductDetail/Tamura/MET-46/?qs=BMSuqZ76GYQKF8a%252b2t3qoA%3D%3D), which differs from the spec' sheet. The response figures on the spec' sheet however are relative to +-1dB at 1 KHz, perhaps this is where the confusion arises. Anyone with further info'?
                  >
                  > --- In softrock40@yahoogroups.com, "g8voip" <g8voi.reeves59@> wrote:
                  > >
                  > > Hi James,
                  > >
                  > > I wonder if you were planning to try and use those transformers in the I/Q lines? Looking at the data sheet, the only reference to bandwidth is 300Hz to 3.5kHz, so probably pretty useless for SDR use.
                  > >
                  > > A better bet might be from Farnell, part number 1689035, OEP Oxford Electric Products A262A7E 600 ohm transformer, quoted spec 35Hz to 35kHz. Like all of these, not cheap £10.10 ex VAT each.
                  > >
                  > > A friend did bring his to show me, and I was surprised to see some improvement when fitting them to my SDR set up. Whether the small improvement is worth the expense is another matter.
                  > >
                  > > 73, Bob G8VOI
                  > >
                  > >
                  > > --- In softrock40@yahoogroups.com, Sid Boyce <sboyce@> wrote:
                  > > >
                  > > > On 09/12/10 21:37, pond.james_pond wrote:
                  > > > > Does anyone know of a UK supplier of these components with reasonable
                  > > > > delivery charges? I flat refuse to pay the £12 delivery Mouser are
                  > > > > asking for 2 £7.92 items.
                  > > > >
                  > > > > Thanks and 73.
                  > > > >
                  > > >
                  > > > Tamura UK in Swindon only seem to stock power transformers. Both Mouser
                  > > > and Digikey will stitch you up for £12 shipping. At RS Components the
                  > > > Triad Magnetics SP-70 ones are £12.66 each (plus VAT??) shipped within
                  > > > 10 working days, so there seems to be no reasonably priced ones
                  > > > available over here.
                  > > > 73 ... Sid.
                  > > > --
                  > > > Sid Boyce ... Hamradio License G3VBV, Licensed Private Pilot
                  > > > Emeritus IBM/Amdahl Mainframes and Sun/Fujitsu Servers Tech Support
                  > > > Senior Staff Specialist, Cricket Coach
                  > > > Microsoft Windows Free Zone - Linux used for all Computing Tasks
                  > > >
                  > >
                  >
                • Roelof Bakker
                  Hello James, I don t know which performance you want to achieve with the audio isolating transformers. However there is a large difference when measured as
                  Message 8 of 13 , Dec 10, 2010
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                    Hello James,

                    I don't know which performance you want to achieve with the audio
                    isolating transformers.
                    However there is a large difference when measured as audio transformer and
                    in actual use in a SDR set up.

                    I have tested an ETAL P1200 transformer terminated by and fed from a 600
                    ohm impedance source.
                    The ETAL P1200 is flat +/- 1 dB between 300 Hz and 5 kHz and falls off
                    pretty fast at higher frequencies.

                    I use two of these transformers between a RX LF Ensemble and an ASUS Xonar
                    D1 audio card.
                    With a 48 kHz sample rate, the response is flat within 1 dB.
                    Using a 96 kHz sample rate, this is 2 dB for a 80 kHz wide band and at the
                    edges the signal is 5 dB down.
                    So nothing to worry about, unless you want to use this receiver as a piece
                    of precision test gear.

                    There have been remarks upon phase and amplitude errors introduced by the
                    use of audio isolating transformers.
                    I use WRplus and it is possible to adjust the sideband suppression to a
                    massive 80 dB with the audio transformers in line.
                    This holds only over a very narrow frequency range.

                    I have adjusted mine for a 10 kHz offset from the LO setting.
                    To retain the sideband suppression, it is mandatory to tune the LO and
                    leave the Tune setting alone.

                    The ETAL types are available from the German Funkamateur Magazine web shop.
                    But there certainly wil be other sources.

                    73,
                    Roelof Bakker, pa0rdt
                  • jbboater
                    I plan to try an audio transformer as well. I am using a shielded audio cable and I plan to cut the wire in half, then solder the transformer between the two
                    Message 9 of 13 , Jan 1, 2011
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                      I plan to try an audio transformer as well. I am using a shielded audio cable and I plan to cut the wire in half, then solder the transformer between the two halves I just cut.

                      However, I am not sure if I need to connect the shield wire from each half together. Seems to me, if I do, then I defeat the purpose of the isolation transformer (interrupting the ground loop).

                      But, I really do not know. So, if someone might already know the answer, I would greatly appreciate it.

                      Basically, do I leave the cut shield 'dangling' or do I connect them together?

                      Thanks!

                      Jeff

                      --- In softrock40@yahoogroups.com, "Alan" <alan4alan@...> wrote:
                      >
                      >
                      > ----- Original Message -----
                      > From: "g8voip"
                      > Subject: [softrock40] Re: Tamura MET-46 transformer sources?
                      >
                      >
                      > >I wonder if you were planning to try and use those transformers in the I/Q
                      > >lines? Looking at the data sheet, the only reference to bandwidth is 300Hz
                      > >to 3.5kHz, so probably pretty useless for SDR use.
                      > > and I was surprised to see some improvement when fitting them to my SDR
                      > > set up. Whether the small improvement is worth the expense is another
                      > > matter.
                      >
                      >
                      > I have tried a couple of transformer types.
                      > One the usual 600/600 modem, the other Pico with a poorer LF like the one
                      > above.
                      > Both seemed to work satisfactorily within their limits but neither would
                      > allow decoding of DRM.
                      >
                      > 73 Alan G4ZFQ
                      >
                    • Brian Lloyd
                      ... Leave the shields isolated. You are correct in thinking that reconnecting the shields would recreate your ground-loop. -- Brian Lloyd, WB6RQN/J79BPL 3191
                      Message 10 of 13 , Jan 1, 2011
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                        On Sat, Jan 1, 2011 at 2:47 PM, jbboater <jburke42@...> wrote:
                         

                        I plan to try an audio transformer as well. I am using a shielded audio cable and I plan to cut the wire in half, then solder the transformer between the two halves I just cut.

                        However, I am not sure if I need to connect the shield wire from each half together. Seems to me, if I do, then I defeat the purpose of the isolation transformer (interrupting the ground loop).

                        But, I really do not know. So, if someone might already know the answer, I would greatly appreciate it.

                        Basically, do I leave the cut shield 'dangling' or do I connect them together?

                        Leave the shields isolated. You are correct in thinking that reconnecting the shields would recreate your ground-loop.

                        --
                        Brian Lloyd, WB6RQN/J79BPL
                        3191 Western Dr.
                        Cameron Park, CA 95682
                        brian@...
                        +1.767.617.1365 (Dominica)
                        +1.931.492.6776 (USA)
                        (+1.931.4.WB6RQN)

                      • jbboater
                        THanks for the quick reply Brian, It just dawned on me, won t I need a transformer for the tip and a second transformer for the ring? If so, how do I connect
                        Message 11 of 13 , Jan 1, 2011
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                          THanks for the quick reply Brian,

                          It just dawned on me, won't I need a transformer for the tip and a second transformer for the ring?

                          If so, how do I connect the return or bottom of the transformer?

                          I would think I would connect two wires to one side of the shield, and they would each connect to both return sides of the transformer.

                          Not sure about this now that I'm about ready to cut and solder some wires...

                          --- In softrock40@yahoogroups.com, Brian Lloyd <brian-wb6rqn@...> wrote:
                          >
                          > On Sat, Jan 1, 2011 at 2:47 PM, jbboater <jburke42@...> wrote:
                          >
                          > >
                          > >
                          > > I plan to try an audio transformer as well. I am using a shielded audio
                          > > cable and I plan to cut the wire in half, then solder the transformer
                          > > between the two halves I just cut.
                          > >
                          > > However, I am not sure if I need to connect the shield wire from each half
                          > > together. Seems to me, if I do, then I defeat the purpose of the isolation
                          > > transformer (interrupting the ground loop).
                          > >
                          > > But, I really do not know. So, if someone might already know the answer, I
                          > > would greatly appreciate it.
                          > >
                          > > Basically, do I leave the cut shield 'dangling' or do I connect them
                          > > together?
                          > >
                          > Leave the shields isolated. You are correct in thinking that reconnecting
                          > the shields would recreate your ground-loop.
                          >
                          > --
                          > Brian Lloyd, WB6RQN/J79BPL
                          > 3191 Western Dr.
                          > Cameron Park, CA 95682
                          > brian@...
                          > +1.767.617.1365 (Dominica)
                          > +1.931.492.6776 (USA)
                          > (+1.931.4.WB6RQN)
                          >
                        • Brian Lloyd
                          ... Yes. You want a separate transformer for both the I and Q channels. ... Both transformers will be connected the same way. The shield coming from the
                          Message 12 of 13 , Jan 1, 2011
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                            On Sat, Jan 1, 2011 at 5:25 PM, jbboater <jburke42@...> wrote:
                             

                            THanks for the quick reply Brian,

                            It just dawned on me, won't I need a transformer for the tip and a second transformer for the ring?

                            Yes. You want a separate transformer for both the I and Q channels. 


                            If so, how do I connect the return or bottom of the transformer?

                            Both transformers will be connected the same way. The shield coming from the SoftRock will be shared by the primaries of the two transformers. The secondaries will share the shield going to your sound-card. 


                            I would think I would connect two wires to one side of the shield, and they would each connect to both return sides of the transformer.

                            Yes.


                            Not sure about this now that I'm about ready to cut and solder some wires...


                            I think you have it.

                            --
                            Brian Lloyd, WB6RQN/J79BPL
                            3191 Western Dr.
                            Cameron Park, CA 95682
                            brian@...
                            +1.767.617.1365 (Dominica)
                            +1.931.492.6776 (USA)
                            (+1.931.4.WB6RQN)

                          • jbboater
                            Hi Brian, Thanks again for your help. I will give this a try today. In case someone else wonders which transformers I am using, based on the information I
                            Message 13 of 13 , Jan 2, 2011
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                              Hi Brian,

                              Thanks again for your help. I will give this a try today. In case someone else wonders which transformers I am using, based on the information I found, I am using the Radio Shack 420-1374 audio isolation transformer.

                              Perhaps not the best, it was the quickest and easiest transformer to find locally.

                              Thanks again,

                              Jeff

                              --- In softrock40@yahoogroups.com, Brian Lloyd <brian-wb6rqn@...> wrote:
                              >
                              > On Sat, Jan 1, 2011 at 5:25 PM, jbboater <jburke42@...> wrote:
                              >
                              > >
                              > >
                              > > THanks for the quick reply Brian,
                              > >
                              > > It just dawned on me, won't I need a transformer for the tip and a second
                              > > transformer for the ring?
                              > >
                              > Yes. You want a separate transformer for both the I and Q channels.
                              >
                              > >
                              > > If so, how do I connect the return or bottom of the transformer?
                              > >
                              > Both transformers will be connected the same way. The shield coming from the
                              > SoftRock will be shared by the primaries of the two transformers. The
                              > secondaries will share the shield going to your sound-card.
                              >
                              > >
                              > > I would think I would connect two wires to one side of the shield, and they
                              > > would each connect to both return sides of the transformer.
                              > >
                              > Yes.
                              >
                              > >
                              > > Not sure about this now that I'm about ready to cut and solder some
                              > > wires...
                              > >
                              >
                              > I think you have it.
                              >
                              > --
                              > Brian Lloyd, WB6RQN/J79BPL
                              > 3191 Western Dr.
                              > Cameron Park, CA 95682
                              > brian@...
                              > +1.767.617.1365 (Dominica)
                              > +1.931.492.6776 (USA)
                              > (+1.931.4.WB6RQN)
                              >
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