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The following footprints are of my CW signals on 2021-March-14 at about 04:00 to 04:20 UTC.

Discussion in 'Antennas, Feedlines, Towers & Rotors' started by NW7US, Mar 15, 2021.

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  1. NW7US

    NW7US Premium Subscriber QRZ Page

    The following footprints are of my CW signals on 2021-March-14 at about 04:00 to 04:20 UTC.


    Location: EM89ad - Ohio
    Antenna: OCD (Off-center Dipole)

    Description of Antenna:

    This is an off-center dipole, with the two legs running East-East-South (approximately 125 degrees of North), and West-West-North (about 306 degrees on the compass). The westward wire (leg) is approximately 107 feet in length, while the eastward leg is about 95 feet in length.

    These legs (an off-center-fed dipole) is directly connected to about 90 feet of 450-ohm ladder line, which is hanging directly below, vertically, the feed point. The feed point is 50 feet above the ground.

    The ladder line terminates (at the 12-feet-above-ground point) to a 4:1 current balun. This current balun then connects to a 100-foot LMR 50-ohm coax, which is running into the radio shack. It is connected via an antenna switch to my Icom IC-7610 transceiver. I am transmitting a 100-watt CW signal using an Icom IC-7610, in the following format:


    The Reverse Beacon Network reports any spotting of this test transmission. The beta mapping interface, at, then maps the resulting spots. To learn more about the RBN, visit, or,

    I show the 20-, 30-, 40-, 60-, 80-, and 160-Meter band footprints.

    I've been capturing these CW transmission spots, at different times of the day, today. I'll get data from several days, at regular intervals, and create a overview of how the antenna appears to be working during this month and under these propagation conditions.

    73 de NW7US dit dit

    KI4ZUQ and PU2OZT like this.
  2. K2XT

    K2XT Premium Subscriber QRZ Page

  3. WA7ARK

    WA7ARK Ham Member QRZ Page

    I do something similar, but I use WSPR, which is part of WSJT-X. In a 24 hour period on say 40m, I can receive about 2500 to 4000 spots from all over the earth without even transmitting. I have set up two antennas, receivers and computers so I can compare two different antennas, A vs B... That generates some big files...
    WD4ELG likes this.
  4. NW7US

    NW7US Premium Subscriber QRZ Page

    Speaking of WSPR...

    I've done some WSPR operation to see my footprint on various bands, because there are a different set of receivers in the WSPR network, than in the Reverse Beacon Network. Using the services, like the Spot Compass chart (below), I can learn more about my antenna.


    This corresponds with the plotting of these 30-Meter transmissions, which is encouraging.

    One of the bands I am quite interested in is 160 Meters. Here is a plot of one night-time hour:


    The feed point is up at the 50-foot point. The legs of the antenna drape down to about 16 feet at their ends. One leg is about 107 feet in length, while the other is about 95 feet in length. The azimuth of the dipole is approximately 284 degrees Westward, and 104 degrees Eastward. The feedline is 450-ohm ladder line that runs from the feedpoint, down about 35 feet, then drapes over to another tree in which is a 4:1 current balun. Total run of 450-ohm ladder line is about 75 feet, give or take a few. The 4:1 current balun then connected to a 100-foot LMR 50-ohm coax that runs to the radio shack (room), terminating to an Icom IC-7610.

    This map illustrates the reception of my 50-watt 160-Meter transmissions between 06:00 UTC to 07:00 UTC on UTC date 17-March-2021. This tells me that the antenna has potential. The next test is to find out what I can hear with this antenna. I may have to put out some beverages.

    73 de NW7US dit dit
  5. N4MU

    N4MU Ham Member QRZ Page

    So did you talk with anybody interesting or just see where you might have? I'm going to put out some beverages today too. They will be half Canadian and half something called a "7 Up"...I suppose for forty meters.
  6. W4HWD

    W4HWD Premium Subscriber QRZ Page

    Yeah. It's called propagation. Next...
  7. NW7US

    NW7US Premium Subscriber QRZ Page

    Oh, what joy is this that bestows on this thread, the unwelcome yet ever present blather? It is the usual (if not expected), habitual drive-by peanut gallery inhabitants, hecklers, all, who are blessing us with their typical pointless babbelings. I'm sure that they all feel so self-fulfilled, having expended the energy to grace yet another thread with their presence.
    K1LKP likes this.
  8. N4MU

    N4MU Ham Member QRZ Page

    Hey, that's pretty good stuff. Pointless babbelings. I like that. Where have I heard that before? Shouldn't that be babblings? Anyway, speaking of pointless...never mind. I've already expended enough energy.
  9. W7UUU

    W7UUU Principal Moderator Lifetime Member 133 Administrator Volunteer Moderator Platinum Subscriber Life Member QRZ Page

    Geez... tough room! The guy simply posts observations of what propagation looks like from his QTH and gets piled on for it. Wow.

    RBN is indeed a lot of fun to play with in this very way - figuring out "where things are working and where they're not" at any given moment.

    When I first got an HF Yagi, I played with RBN a lot just being amazed at watching a tiny 1 watt signal propagate around the world, following where the beam was aimed.

  10. K2CD

    K2CD Premium Subscriber QRZ Page

    Must be a slow news day. I found the post interesting. Thanks, OP.

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