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PK loop power supply problem

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  • JH Richards
    G day mates -- I purchased an active SWL receiving loop antenna from PK s Loop Antennas in Australia, URL = http://www.amradioantennas.com/ I purchased a USA
    Message 1 of 6 , Jul 2, 2007
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      G'day mates -- I purchased an active SWL receiving loop antenna from
      PK's Loop Antennas in Australia, URL = http://www.amradioantennas.com/

      I purchased a USA mains AC/DC power adapter at good ol' RadioShack
      which, unfortunately, gives off harmful pulsing interference which
      sounds like a rat-a-tat-a-tat-a-tat-a-tat and which quits when I
      unplug it. Interesting, it slows down and decelerates for a few
      seconds after I unplug it - kinda like a motor winding down. I put a
      couple of sound "bytes" in the files section labeled appropriately.

      Wall wart type 12 volt power supply is Catalog No. 273-1775

      Do I just need a different power supply (maybe this one is a switching
      type...) and maybe do I need a regulated linear type supply? Or... what?

      Any ideas how to power my loop antenna without this interference?

      Thanks -- Loop antenna works OK, except for this pulsing interference.

      /////////////// Richards /////////////////
    • ceboyd
      Yo Richards: Try a battery. Not to be accused of being flippant, but invest in a set of rechargables with charger and enjoy noise free reception. Oh, how s
      Message 2 of 6 , Jul 2, 2007
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        Yo Richards: Try a battery. Not to be accused of being flippant, but invest
        in a set of rechargables with charger and enjoy noise free reception. Oh,
        how's the new antenna farm going? Take care: theboyd
        ----- Original Message -----
        From: "JH Richards" <jruing@...>
        To: <loopantennas@yahoogroups.com>
        Sent: Monday, July 02, 2007 10:51 PM
        Subject: [loopantennas] PK loop power supply problem


        > G'day mates -- I purchased an active SWL receiving loop antenna from
        > PK's Loop Antennas in Australia, URL = http://www.amradioantennas.com/
      • mwwong@qbe.com.my
        Hi Richards, i could not answer your query on the DC adapter but i would like to ask on another matter which is on the PK s Loop performance... are your
        Message 3 of 6 , Jul 2, 2007
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          Hi Richards,

          i could not answer your query on the DC adapter but i would like to
          ask on another matter which is on the PK's Loop performance...

          are your referring to the SW620 model and if so, how do your fare its
          reception ability compared to a conventional random long wire antenna?...

          best regards,

          Alan Wong





          "JH Richards" <jruing@...>
          Sent by: loopantennas@yahoogroups.com
          07/03/2007 12:51 PM
          Please respond to loopantennas

          To: loopantennas@yahoogroups.com
          cc:
          Subject: [loopantennas] PK loop power supply problem


          G'day mates -- I purchased an active SWL receiving loop antenna from
          PK's Loop Antennas in Australia, URL = http://www.amradioantennas.com/

          I purchased a USA mains AC/DC power adapter at good ol' RadioShack
          which, unfortunately, gives off harmful pulsing interference which
          sounds like a rat-a-tat-a-tat-a-tat-a-tat and which quits when I
          unplug it. Interesting, it slows down and decelerates for a few
          seconds after I unplug it - kinda like a motor winding down. I put a
          couple of sound "bytes" in the files section labeled appropriately.

          Wall wart type 12 volt power supply is Catalog No. 273-1775

          Do I just need a different power supply (maybe this one is a switching
          type...) and maybe do I need a regulated linear type supply? Or... what?

          Any ideas how to power my loop antenna without this interference?

          Thanks -- Loop antenna works OK, except for this pulsing interference.

          /////////////// Richards /////////////////




          [Non-text portions of this message have been removed]
        • Richards
          Hi Guys -- and especially Mr. Boyd = FALSE ALARM !! SORRY !! I for got that I had another 12 volt power supply that I use with various DSP filters. It is
          Message 4 of 6 , Jul 2, 2007
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            Hi Guys -- and especially Mr. Boyd =

            FALSE ALARM !! SORRY !!

            I for got that I had another 12 volt power supply
            that I use with various DSP filters. It is also
            by RadioShack, also, but much larger, Cat No. 273-1653B
            AND IT CAUSES NO SUCH NOISE ! Hurray!!

            Boyd - That battery idea is a good one. I will
            have to make one up from, perhaps, NiMH cells and an
            appropriate battery holder and a project case to sit
            by the loop antenna amp/tuner unit. That would be
            a good idea in case the power goes out, and I can get
            listening with NO RFI/EMI from the house or the
            neighbors. I like it when the power fails.

            Also, regarding my new antenna farm, it is finally
            taking shape with a nice 20 foot high 80 foot
            random/long wire running kinda East-West and
            employing a 9:1 balun/transformer and coax cable
            (with a 1:1 current type line isolation balun in
            line on the coax) and an optional earth ground that
            can be placed on the balun coax at the point where
            the feed line connects to the transformer/antenna
            element. (I like to switch it in and out to see
            if it matters - and generally it does not.) The
            balun manufacturer said it could go either way
            depending on the noise situation on the coax outer
            shield... does not seem to matter in my QTH. Cannot
            explain why as I figured it should matter.

            I am also setting up to deploy my trusty old Antenna
            Supermarket's Eavesdropper trapped dipole - maybe in
            the attic where it was at my last home and used for
            an upstairs radio bedside - or possibly stretch in
            the back yard. XYL and I are working on where to
            place it to have good effect and low visibility.

            I also have a short 40 foot random wire concealed and
            running along under the railing on my rear deck that
            and I use for comparison with the bigger random wire
            running perpendicular to it. So far, it is noisier
            as it uses a simple insulated wire as a feed line and
            does not use a balun/transformer or coax like the
            other one. I connect it to the high impedance lugs
            on the radio for comparison. The bigger one is
            noticeably quieter and has stronger signal capture.

            I have also deployed the above-discussed small magnetic
            loop antenna (it is only about 14 inches diameter) and
            will be installed about fifteen feet above ground and
            about 15 to 20 feet away from the house by the end
            of Wednesday July 4 holiday. It works pretty well,
            considering its very small size. Much better with a
            quiet power supply, too!

            I have also deployed 1) a Sony AN-LPN1 portable loop
            antenna and 2) a Degen/Kaito KA-33 loop antenna -- and
            oddly enough the Kaito loop works better in my QTH !
            The Sony antenna either works as well as, but not better,
            or it performs slightly with more noise and hiss, than
            the Kaito product. I cannot explain it, but it does.
            These are used with a portable Realistic DX-398 or
            Kaito 1102 I use on the night stand when I cannot get
            to sleep right away. The work OK, but a short 20
            foot sloper running from the bedroom window out away
            from the house on an angle attached to a weight in the
            yard works just a bit better. These two loops do not
            so as well in my downstairs radio room (garden level
            with belt high window ledges). This is, of course, as
            expected.

            Finally, I will soon deploy and test my home-built
            North Country Active Antenna - built with some very big
            Internet coaching from one of our prominent members. I
            am thinking it will work about as well as my new Australian
            small loop that was the original subject of this thread.

            I may even try the Wellbrook Loop... just have not gotten
            up the nerve to order it... (just purchase a new digital
            SLR camera system... so kinda feeling guilty today... but
            I will get over that soon enough... as soon as the XYL
            forgets ... ) ;-)

            THEN ... I will complete my studies and take the Tech Test
            and work on some HF transmitting antennas (as I will take
            General Test soon thereafter...)

            Sorry this got long and complicated - BUT IS IS REALLY GOOD
            TO GET A DECENT RECEIVING ANTENNA UP and get some decent
            reception at my new home. Moving - remodeling - selling old
            home and a condo - and getting settled in has been more
            hectic and involved than expected. Nice to finally get
            feeling at home here.

            Cannot express how much I appreciate the several encouraging
            notes you have sent over the past few months. Thanks.


            Happy trails. /////// Richards ////////
            ========================================================


            ceboyd wrote:
            > Yo Richards: Try a battery. Not to be accused of being flippant, but invest
            > in a set of rechargables with charger and enjoy noise free reception. Oh,
            > how's the new antenna farm going? Take care: theboyd
          • DavidGriffin
            Not a direct solution, but you might want to look into buying a small regulated 12 vdc power supply, such as an Astron RS 7A (7 amp) unit and making up
            Message 5 of 6 , Jul 3, 2007
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              Not a direct solution, but you might want to look into buying a small
              regulated 12 vdc power supply, such as an Astron RS 7A (7 amp) unit and
              making up "cables" (of cheap speaker wire, as long you you keep plus and
              minus obvious) to a variety of plugs, also available from RS. And a
              soldering pencil. The Astron is not a switching supply and I've never
              heard any RF noise from either of my mine.
              Dave


              [Non-text portions of this message have been removed]
            • Richards
              Yes, I have that SW model, but mine was specifically modified by the seller to cover 3-13 MHz - rather than the 6-20 MHz range on their standard model shown on
              Message 6 of 6 , Jul 3, 2007
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                Yes, I have that SW model, but mine was specifically modified
                by the seller to cover 3-13 MHz - rather than the 6-20 MHz
                range on their standard model shown on the web page.

                Although I am still playing with it and testing its performance,
                my initial feel is that it is equal in signal capture and noise
                to a 40 foot long wire connected to the high impedance antenna
                connector on my Kenwood R-5000 and that wire runs just under
                the top rail on my rear deck on the back of the house - running
                parallel to the house about ten feet away. It is not, however,
                as clear and strong (but real close) as what I get on my
                75 foot elevated long wire/9:1 balun-transformer/ coax-fed
                antenna hanging over the back yard that runs in a E-W direction.

                I plan to move it some tonight and see how it works in different
                orientations and at different heights and distances from the
                house. More on this tomorrow...

                First impression is that it works pretty darned well for
                how small it is. Wife was not all that keen on my having
                to put two holes in the house wall for the two cables
                running to it, but she's a good sport and her grumbling
                is lower than the antenna's inherent noise floor, so her
                whining is not too distracting... ;-)

                /////////// Just MY take. Richards //////////
                =========================================================
                mwwong@... wrote:
                .
                >
                > are your referring to the SW620 model and if so, how do your fare its
                > reception ability compared to a conventional random long wire antenna?...
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