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Re: MTR report

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  • bill_w4zv
    ... Any antenna longer than ~40 is a non-starter for me. Ideally I want to cover both 40 and 20 with one 33 piece of wire and no lumps to get hung up in
    Message 1 of 24 , Mar 28, 2013
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      --- In AT_Sprint@yahoogroups.com, "ve3wmb" <mbabineau@...> wrote:
      >
      > Another option for 40m/20m would be to go with a 66 ft EFHW

      Any antenna longer than ~40' is a non-starter for me. Ideally I want to cover both 40 and 20 with one 33' piece of wire and no "lumps" to get hung up in tree branches. Configuring a 33' wire on 40 as a 1/4 wave vertical will work but it requires too complex a ground system for portable operation. On 40m I've been able to tune a 33' wire > PAR EF-10/40 matchbox > ZM-2 tuner. I'm in the process of testing to see if that radiates well enough to be heard. I don't need much efficiency on 40 since most contacts are within a few hundred miles. Will post here if RBNs can hear me!

      73, Bill W4ZV
    • bill_w4zv
      ... This is a straight 33 vertical wire PAR EF-10/40 ZM-2. ZM-2 tuning was a bit critical but this may be good enough : W4AX W4ZV 1 dB 248 miles WSW
      Message 2 of 24 , Mar 28, 2013
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        --- In AT_Sprint@yahoogroups.com, "bill_w4zv" <btippett@...> wrote:
        >
        >
        >
        > --- In AT_Sprint@yahoogroups.com, "ve3wmb" <mbabineau@> wrote:
        > >
        > > Another option for 40m/20m would be to go with a 66 ft EFHW
        >
        > Any antenna longer than ~40' is a non-starter for me. Ideally I want to cover both 40 and 20 with one 33' piece of wire and no "lumps" to get hung up in tree branches. Configuring a 33' wire on 40 as a 1/4 wave vertical will work but it requires too complex a ground system for portable operation. On 40m I've been able to tune a 33' wire > PAR EF-10/40 matchbox > ZM-2 tuner. I'm in the process of testing to see if that radiates well enough to be heard. I don't need much efficiency on 40 since most contacts are within a few hundred miles. Will post here if RBNs can hear me!

        This is a straight 33' vertical wire > PAR EF-10/40 > ZM-2. ZM-2 tuning was a bit critical but this may be "good enough":

        W4AX W4ZV 1 dB 248 miles WSW
        WZ7I W4ZV 12 dB 443 miles NE
        W4KKN W4ZV 11 dB 270 miles NNE
        NY3A W4ZV 14 dB 353 miles NNE

        My next experiment was testing a trapped 20/30 EFHW vertical about 40.5' overall through the same ZM-2 tuner. No grounds for either test BTW.

        W4KKN K4URE 13 dB 270 miles NNE
        NY3A K4URE 21 dB 353 miles NNE
        W3LPL K4URE 8 dB 320 miles NNE
        WZ7I K4URE 22 dB 443 miles NE
        K1TTT K4URE 9 dB 622 miles NE

        This was a little better since the overall length is 40.5' versus 33' with some center loading due to the 20m trap. Tuning was not quite as critical on the ZM-2 compared to the first antenna. I picked up a couple of new RBNs but dropped W4AX in GA. The price for the better signal is longer wire plus one "lump" due to the 20m trap.

        These tests were ~20 minutes apart but more testing will be done at different times of day. I need to determine if the 33' wire alone is sufficient for 40m since I really prefer its physical simplicity.

        73, Bill W4ZV
      • Steven Weber
        ... The problem with a 33 foot antenna on 40 is that is a 1/4 wave and therefore low impedance of about 50 ohms, so a tuner designed for high impedance isn t
        Message 3 of 24 , Mar 28, 2013
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          > These tests were ~20 minutes apart but more testing will be done at
          > different times of day. I need to determine if the 33' wire alone is
          > sufficient for 40m since I really prefer its physical simplicity.
          >

          The problem with a 33 foot antenna on 40 is that is a 1/4 wave and therefore
          low impedance of about 50 ohms, so a tuner designed for high impedance isn't
          going to like it. Making it a bit longer will rise the impedance, making it
          easier to match with a high impedance tuner.

          The ideal 40/20 EFHW is a bit shorter then 66 feet to make the impedance a
          bit lower then really high. That's why I recommend about 51 feet for my L
          tuner. This is a litte shorter then 1/2 wave on 40 and full wave on 20. For
          30, different length is required, since you want to be in the neighbor hood
          of 1/2 wave or multipels for an EFHW.

          When they added the non-harmomically related WARC bands, it tossed a monkey
          wrench into multi-band antenna design...

          Steve KD1JV
        • russellhulett
          I never investigated why, but using ATS-3B portable from Poirier Lake, Ontario, a 34 wire connected to a KI6J EFHW tuner worked well on 20M and 30M with no
          Message 4 of 24 , Mar 28, 2013
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            I never investigated why, but using ATS-3B portable from Poirier Lake, Ontario, a 34' wire connected to a KI6J EFHW tuner worked well on 20M and 30M with no setting changes and no counterpoise. Others reported same experience which is why I only took the 20M and 30M modules with me to the lake.

            Have contemplated building a fixed matching network based on the settings from that tuner to go with my new MTR which plan building for 20 and 30.

            73, Curt KB5JO
          • ve3wmb
            Steve et al : I have used the recommended 51 footer with my ALT tuner for years and it does match very well on 40m / 20m. If you want to use it on 30m the
            Message 5 of 24 , Mar 29, 2013
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              Steve et al :

              I have used the recommended 51 footer with my ALT tuner for years and it does match
              very well on 40m / 20m. If you want to use it on 30m the match isn't quite
              as good but rolling up a couple of feet of the wire at the end fixes it for 30m.

              Michael VE3WMB

              P.S. The ALT is a brilliant design. Very simple but effective, the only issue of course
              is making sure that you don't lose the little 2 pin headers, but I found that using the
              pliers on my little leatherman tool to move the headers around is a lot easier than
              fingers.


              --- In AT_Sprint@yahoogroups.com, "Steven Weber" <steve.kd1jv@...> wrote:
              >
              > > These tests were ~20 minutes apart but more testing will be done at
              > > different times of day. I need to determine if the 33' wire alone is
              > > sufficient for 40m since I really prefer its physical simplicity.
              > >
              >
              > The problem with a 33 foot antenna on 40 is that is a 1/4 wave and therefore
              > low impedance of about 50 ohms, so a tuner designed for high impedance isn't
              > going to like it. Making it a bit longer will rise the impedance, making it
              > easier to match with a high impedance tuner.
              >
              > The ideal 40/20 EFHW is a bit shorter then 66 feet to make the impedance a
              > bit lower then really high. That's why I recommend about 51 feet for my L
              > tuner. This is a litte shorter then 1/2 wave on 40 and full wave on 20. For
              > 30, different length is required, since you want to be in the neighbor hood
              > of 1/2 wave or multipels for an EFHW.
              >
              > When they added the non-harmomically related WARC bands, it tossed a monkey
              > wrench into multi-band antenna design...
              >
              > Steve KD1JV
              >
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