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Looking for 3 band receiving loop...

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  • n6vl
    Hi, I am looking for a receiving loop I can use on the 160, 80, and 40 meters ham bands. It can be either an indoor loop in my ham shack. Or it can be a larger
    Message 1 of 10 , Mar 31, 2007
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      Hi,

      I am looking for a receiving loop I can use on the 160, 80, and 40
      meters ham bands. It can be either an indoor loop in my ham shack. Or
      it can be a larger outdoor one. I hope to find one I can use on all the
      lower HF ham bands. Many designs are for single band. Perhaps there is
      a design on posted on this group I simply haven't noticed.

      Thanks in advance!

      Steve N6VL
    • gplynas
      Hi Steve, Many years ago I designed a broadband loop for monitoring radio-navigation beacons which had to cover the frequency range of 195 kHz to 480 kHz. Our
      Message 2 of 10 , Apr 1, 2007
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        Hi Steve,
        Many years ago I designed a broadband loop for monitoring
        radio-navigation beacons which had to cover the frequency range of 195
        kHz to 480 kHz. Our previous loops were tuned single-frequency. I
        designed this one by looking at the loop as the "inductor" in a Pi
        network, with a transformation ratio from (radiation resistance + loss
        resistance) to the input impedance of the amplifier, and with a
        break-point above the highest frequency. I fed this into an FET
        amplifier with high input impedance. A resistor of about 10k
        furnished a return to ground at the amplifier input and stabilized the
        gain. The whole circuit was then feed with +15 VDC through the coax
        from the receiver.

        This worked well, with a response that was reasonably flat over more
        than 2 octaves. I think the same concept could be used from 160M to
        40M. By design, I was able to reject the broadcast band signals which
        could overload a broadband design.
        Regards,
        Paul Lynas
        WA5LFY

        --- In loopantennas@yahoogroups.com, "n6vl" <n6vl@...> wrote:
        >
        > Hi,
        >
        > I am looking for a receiving loop I can use on the 160, 80, and 40
        > meters ham bands. It can be either an indoor loop in my ham shack. Or
        > it can be a larger outdoor one. I hope to find one I can use on all the
        > lower HF ham bands. Many designs are for single band. Perhaps there is
        > a design on posted on this group I simply haven't noticed.
        >
        > Thanks in advance!
        >
        > Steve N6VL
        >
      • David Atkins
        Paul, I, for one would be very interested to see your loop design ... From: loopantennas@yahoogroups.com [mailto:loopantennas@yahoogroups.com]On Behalf Of
        Message 3 of 10 , Apr 1, 2007
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          Paul,

          I, for one would be very interested to see your loop design


          -----Original Message-----
          From: loopantennas@yahoogroups.com
          [mailto:loopantennas@yahoogroups.com]On Behalf Of gplynas
          Sent: 01 April 2007 15:19
          To: loopantennas@yahoogroups.com
          Subject: [loopantennas] Re: Looking for 3 band receiving loop...


          Hi Steve,
          Many years ago I designed a broadband loop for monitoring
          radio-navigation beacons which had to cover the frequency range of 195
          kHz to 480 kHz. Our previous loops were tuned single-frequency. I
          designed this one by looking at the loop as the "inductor" in a Pi
          network, with a transformation ratio from (radiation resistance + loss
          resistance) to the input impedance of the amplifier, and with a
          break-point above the highest frequency. I fed this into an FET
          amplifier with high input impedance. A resistor of about 10k
          furnished a return to ground at the amplifier input and stabilized the
          gain. The whole circuit was then feed with +15 VDC through the coax
          from the receiver.

          This worked well, with a response that was reasonably flat over more
          than 2 octaves. I think the same concept could be used from 160M to
          40M. By design, I was able to reject the broadcast band signals which
          could overload a broadband design.
          Regards,
          Paul Lynas
          WA5LFY
        • c.e.boyd
          Hi Paul: Do you recall the values for the coil and caps you used for this LW antenna? Also to modify this antenna for the low freq ham bands, (not 60) what
          Message 4 of 10 , Apr 1, 2007
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            Hi Paul: Do you recall the values for the coil and caps you used for this LW
            antenna? Also to modify this antenna for the low freq ham bands, (not 60)
            what would be the necessary values? Thanks: theboyd
            ----- Original Message -----
            From: "gplynas" <gplynas@...>
            To: <loopantennas@yahoogroups.com>
            Sent: Sunday, April 01, 2007 8:19 AM
            Subject: [loopantennas] Re: Looking for 3 band receiving loop...


            > Hi Steve,
            > Many years ago I designed a broadband loop for monitoring
            > radio-navigation beacons which had to cover the frequency range of 195
            > kHz to 480 kHz. Our previous loops were tuned single-frequency. I
            > designed this one by looking at the loop as the "inductor" in a Pi
            > network, with a transformation ratio from (radiation resistance + loss
            > resistance) to the input impedance of the amplifier, and with a
            > break-point above the highest frequency. I fed this into an FET
            > amplifier with high input impedance. A resistor of about 10k
            > furnished a return to ground at the amplifier input and stabilized the
            > gain. The whole circuit was then feed with +15 VDC through the coax
            > from the receiver.
            >
            > This worked well, with a response that was reasonably flat over more
            > than 2 octaves. I think the same concept could be used from 160M to
            > 40M. By design, I was able to reject the broadcast band signals which
            > could overload a broadband design.
            > Regards,
            > Paul Lynas
            > WA5LFY
          • Paul Birke
            Dear Paul that seems like a very clever idea to make the loop part of some input filter system is there a history to this, I have never seen this mentioned
            Message 5 of 10 , Apr 1, 2007
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              Dear Paul

              that seems like a very clever idea to make the loop part of some input filter system

              is there a history to this, I have never seen this mentioned before then again what do I know

              anyways it stikes me one could has many variations of the basic Loop looked as and inductance in front end R L C filter circuits or even active circuits IMHO

              best
              Paul Birke PEng
              Guelph


              ----- Original Message ----
              From: gplynas <gplynas@...>
              To: loopantennas@yahoogroups.com
              Sent: Sunday, April 1, 2007 10:19:27 AM
              Subject: [loopantennas] Re: Looking for 3 band receiving loop...

              Hi Steve,
              Many years ago I designed a broadband loop for monitoring
              radio-navigation beacons which had to cover the frequency range of 195
              kHz to 480 kHz. Our previous loops were tuned single-frequency. I
              designed this one by looking at the loop as the "inductor" in a Pi
              network, with a transformation ratio from (radiation resistance + loss
              resistance) to the input impedance of the amplifier, and with a
              break-point above the highest frequency. I fed this into an FET
              amplifier with high input impedance. A resistor of about 10k
              furnished a return to ground at the amplifier input and stabilized the
              gain. The whole circuit was then feed with +15 VDC through the coax
              from the receiver.

              This worked well, with a response that was reasonably flat over more
              than 2 octaves. I think the same concept could be used from 160M to
              40M. By design, I was able to reject the broadcast band signals which
              could overload a broadband design.
              Regards,
              Paul Lynas
              WA5LFY

              --- In loopantennas@ yahoogroups. com, "n6vl" <n6vl@...> wrote:
              >
              > Hi,
              >
              > I am looking for a receiving loop I can use on the 160, 80, and 40
              > meters ham bands. It can be either an indoor loop in my ham shack. Or
              > it can be a larger outdoor one. I hope to find one I can use on all the
              > lower HF ham bands. Many designs are for single band. Perhaps there is
              > a design on posted on this group I simply haven't noticed.
              >
              > Thanks in advance!
              >
              > Steve N6VL
              >




              [Non-text portions of this message have been removed]
            • gplynas
              Hi Paul, My design of this loop dates from the late 70s to the early 80s so it has been a few years. I came up with the idea of placing the loop within the
              Message 6 of 10 , Apr 1, 2007
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                Hi Paul, My design of this loop dates from the late '70s to the early
                '80s so it has been a few years. I came up with the idea of placing
                the loop within the filter after looking at the flatness of response
                and impedance of a three element Butterworth type filter. The
                radiation resistance plus loop losses can be converted to an
                equivalent input impedance for design purposes, with the filter
                designed around the inductance of the loop. I looked for my notes on
                the design, but what remains is from memory. I'll see if I can put
                together a paper design that we can try.

                Best Regards,
                Paul Lynas
                WA5LFY

                --- In loopantennas@yahoogroups.com, Paul Birke <nonlinear@...> wrote:
                >
                > Dear Paul
                >
                > that seems like a very clever idea to make the loop part of some
                input filter system
                >
                > is there a history to this, I have never seen this mentioned before
                then again what do I know
                >
                > anyways it stikes me one could has many variations of the basic Loop
                looked as and inductance in front end R L C filter circuits or even
                active circuits IMHO
                >
                > best
                > Paul Birke PEng
                > Guelph
                >
                >
                > ----- Original Message ----
                > From: gplynas <gplynas@...>
                > To: loopantennas@yahoogroups.com
                > Sent: Sunday, April 1, 2007 10:19:27 AM
                > Subject: [loopantennas] Re: Looking for 3 band receiving loop...
                >
                > Hi Steve,
                > Many years ago I designed a broadband loop for monitoring
                > radio-navigation beacons which had to cover the frequency range of 195
                > kHz to 480 kHz. Our previous loops were tuned single-frequency. I
                > designed this one by looking at the loop as the "inductor" in a Pi
                > network, with a transformation ratio from (radiation resistance + loss
                > resistance) to the input impedance of the amplifier, and with a
                > break-point above the highest frequency. I fed this into an FET
                > amplifier with high input impedance. A resistor of about 10k
                > furnished a return to ground at the amplifier input and stabilized the
                > gain. The whole circuit was then feed with +15 VDC through the coax
                > from the receiver.
                >
                > This worked well, with a response that was reasonably flat over more
                > than 2 octaves. I think the same concept could be used from 160M to
                > 40M. By design, I was able to reject the broadcast band signals which
                > could overload a broadband design.
                > Regards,
                > Paul Lynas
                > WA5LFY
                >
                > --- In loopantennas@ yahoogroups. com, "n6vl" <n6vl@> wrote:
                > >
                > > Hi,
                > >
                > > I am looking for a receiving loop I can use on the 160, 80, and 40
                > > meters ham bands. It can be either an indoor loop in my ham shack. Or
                > > it can be a larger outdoor one. I hope to find one I can use on
                all the
                > > lower HF ham bands. Many designs are for single band. Perhaps
                there is
                > > a design on posted on this group I simply haven't noticed.
                > >
                > > Thanks in advance!
                > >
                > > Steve N6VL
                > >
                >
                >
                >
                >
                > [Non-text portions of this message have been removed]
                >
              • Paul Birke
                Dear Paul ok great -- again such a clever idea the embedding of the antenna loop (or loops if one wanted to get fancy) in a number of filter
                Message 7 of 10 , Apr 1, 2007
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                  Dear Paul

                  ok great -- again such a clever idea the embedding of the antenna loop (or loops if one wanted to get fancy) in a number of filter configurations--like you say Butterworth being one of a few

                  >>the mind spins on this one<<

                  could you widen the bandwidth by effectively lowering the Q of the inherent tuned circuit: i,e.;
                  once you have caps there you are talking about resonance

                  but I am thinking of something with a low and high pass together effectively a a bandpass circuit with the loop in the middle so it was not a sharply turned as a tuned loop if you get my drift here

                  could one made a filter with the loop or loops having an extended bandwidth but which sharp sides and of course enjoy the better signal to noise ratio and yet preserve the directional characteristics which should remain purely a function of the loop etc

                  just musing I guess

                  best
                  Paul


                  ----- Original Message ----
                  From: gplynas <gplynas@...>
                  To: loopantennas@yahoogroups.com
                  Sent: Sunday, April 1, 2007 4:10:39 PM
                  Subject: [loopantennas] Re: Looking for 3 band receiving loop...

                  Hi Paul, My design of this loop dates from the late '70s to the early
                  '80s so it has been a few years. I came up with the idea of placing
                  the loop within the filter after looking at the flatness of response
                  and impedance of a three element Butterworth type filter. The
                  radiation resistance plus loop losses can be converted to an
                  equivalent input impedance for design purposes, with the filter
                  designed around the inductance of the loop. I looked for my notes on
                  the design, but what remains is from memory. I'll see if I can put
                  together a paper design that we can try.

                  Best Regards,
                  Paul Lynas
                  WA5LFY

                  --- In loopantennas@ yahoogroups. com, Paul Birke <nonlinear@. ..> wrote:
                  >
                  > Dear Paul
                  >
                  > that seems like a very clever idea to make the loop part of some
                  input filter system
                  >
                  > is there a history to this, I have never seen this mentioned before
                  then again what do I know
                  >
                  > anyways it stikes me one could has many variations of the basic Loop
                  looked as and inductance in front end R L C filter circuits or even
                  active circuits IMHO
                  >
                  > best
                  > Paul Birke PEng
                  > Guelph
                  >
                  >
                  > ----- Original Message ----
                  > From: gplynas <gplynas@... >
                  > To: loopantennas@ yahoogroups. com
                  > Sent: Sunday, April 1, 2007 10:19:27 AM
                  > Subject: [loopantennas] Re: Looking for 3 band receiving loop...
                  >
                  > Hi Steve,
                  > Many years ago I designed a broadband loop for monitoring
                  > radio-navigation beacons which had to cover the frequency range of 195
                  > kHz to 480 kHz. Our previous loops were tuned single-frequency. I
                  > designed this one by looking at the loop as the "inductor" in a Pi
                  > network, with a transformation ratio from (radiation resistance + loss
                  > resistance) to the input impedance of the amplifier, and with a
                  > break-point above the highest frequency. I fed this into an FET
                  > amplifier with high input impedance. A resistor of about 10k
                  > furnished a return to ground at the amplifier input and stabilized the
                  > gain. The whole circuit was then feed with +15 VDC through the coax
                  > from the receiver.
                  >
                  > This worked well, with a response that was reasonably flat over more
                  > than 2 octaves. I think the same concept could be used from 160M to
                  > 40M. By design, I was able to reject the broadcast band signals which
                  > could overload a broadband design.
                  > Regards,
                  > Paul Lynas
                  > WA5LFY
                  >
                  > --- In loopantennas@ yahoogroups. com, "n6vl" <n6vl@> wrote:
                  > >
                  > > Hi,
                  > >
                  > > I am looking for a receiving loop I can use on the 160, 80, and 40
                  > > meters ham bands. It can be either an indoor loop in my ham shack. Or
                  > > it can be a larger outdoor one. I hope to find one I can use on
                  all the
                  > > lower HF ham bands. Many designs are for single band. Perhaps
                  there is
                  > > a design on posted on this group I simply haven't noticed.
                  > >
                  > > Thanks in advance!
                  > >
                  > > Steve N6VL
                  > >
                  >
                  >
                  >
                  >
                  > [Non-text portions of this message have been removed]
                  >




                  [Non-text portions of this message have been removed]
                • n6vl
                  Hi Paul, In my case I don t need the preamp. I use an ICOM 756PROII which has a preamp. In fact on the lower HF bands, I throw in 6 or 12 db of attentuation to
                  Message 8 of 10 , Apr 1, 2007
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                    Hi Paul,

                    In my case I don't need the preamp. I use an ICOM 756PROII which has
                    a preamp. In fact on the lower HF bands, I throw in 6 or 12 db of
                    attentuation to aid reception in noisy conditions.

                    I am trying to visualize your loop. It has a little less range than
                    what I desire. Multiplying by a factor of 10, your loop would span
                    from 1.95 to 4.8 MHz. Am I asking too great of a range for a single
                    loop. It is common to get a loop work 160 and 80 meters or 80 and 40
                    meters.

                    I have looked at loop design at http://www.hard-core-
                    dx.com/nordicdx/antenna/loop/coaxloop.html. It uses two shielded coax
                    loops in the same plane with a common feed. The loop at this URL is
                    for 80 and 160 meters. I need 80 and 40 meters at this time. 160
                    meter can come later as I don't have a decent transmitting antenna
                    right now.

                    I don't often see receiving loops for 40 meters and very rarely for
                    any higher HF bands. I have been using a diagonally polarized delta
                    loop 225 feet in circumfernce for transmitting on 40 and 80 meters. I
                    started using a 44 foot dipole centered fed with balanced line on 30
                    meters and above as it gives a nice broadside pattern up through 10
                    meters. I notice this dipole has a better S/N ratio 40 and 80 meters.
                    I adjust the balanced tuner for maximun signal and don't worry about
                    SWR. It definitely gives a few db of noise reduction on reception. I
                    am baffled that the dipole hears better since loops are often
                    credited as good receiving antennas in terms of S/N ratio. The large
                    delta loop is still used to transmit on 40 and 80 meters.

                    I hope to find a loop to give me even better S/N ratios than the 44
                    foot dipole. I am open to a desktop unit in the shack or something in
                    my backyard. I have the right rig for separate receive antennas and
                    would like to try a receiving loop since summer is coming and the
                    static levels will increase.

                    Paul, could you comment in a little more detail about your design and
                    how I might approach this for the lower HF bands.

                    73,

                    Steve N6VL
                  • Jim Morrison
                    ... Hi Steve, W4RNL has several articles on the Loop antenna, but this one seems like a good place to start for your question:
                    Message 9 of 10 , Apr 9, 2007
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                      --- "n6vl" <n6vl@...> wrote:
                      > I am looking for a receiving loop I can use on the 160, 80, and 40
                      > meters ham bands.

                      Hi Steve,

                      W4RNL has several articles on the Loop antenna, but this one
                      seems like a good place to start for your question:
                      http://www.cebik.com/fdim/atl1.html

                      Poke around here for some additional Loop info:
                      http://cebik.com/radio.html

                      73, Jim N9GTM
                    • n6vl
                      Jim, Thanks for the info. I already a semi-horizontal loop now. My main is interest is in small receiving loops with improve S/N ratio and not for
                      Message 10 of 10 , Apr 14, 2007
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                        Jim,

                        Thanks for the info. I already a semi-horizontal loop now. My main is
                        interest is in small receiving loops with improve S/N ratio and not for
                        transmitting. Many of the loops in this group are for reception only.

                        73,

                        Steve N6VL
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