Phased Verticals

Discussion in 'Antennas, Feedlines, Towers & Rotors' started by KM4ZCT, Sep 8, 2017.

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  1. KM4ZCT

    KM4ZCT XML Subscriber QRZ Page

    Hi,

    Recently I just finished installing a Hygain AV-18S vertical and noticed in the manual a section about phasing verticals. Now, I'll be honest and say I don't know much about phasing verticals but having some gain in a desired direction is appealing to me. Has anyone here used phased verticals with any success? I do have a few concerns with it because of the slope in my backyard. For it to be a at least a 1/2 of a wavelength long on 20m, the difference in height of the two antennas would be pretty drastic. Do the verticals have to be equal height when they're phased or does something like height not matter? And how critical is the spacing in wavelengths? And correct me if I'm wrong, the two types of firing arrangements are on the ends and the broadside of the antennas correct? I'm just trying to figure this out in my head before going any further to see if it's even feasible to stick another vertical in my backyard.
     
  2. W5DXP

    W5DXP Ham Member QRZ Page

    What is the slope of your backyard in degrees?
     
  3. AI3V

    AI3V Ham Member QRZ Page

    Yes, I have "phased" many antennas, of various types.

    You can get almost 2.5 DB if gain if you do EVERYTHING perfect.

    You can vary the direction of the beam (and null) by changing the relitive phase between elements, either by physical spacing or electrical delay.

    You can use schemes other than broadside and end fire. Cardiod is the next most usefull.

    Sloping land affects the "take off angle" compared to the far horizon.

    I would not waste time with trapped verticals over anything less than a perfect ground radial field (50 or more 1/4 wave radials per antenna) if I could install almost anything else, a 3 El yagi-uda on 20meters will smoke a 2 element trapped vertical "array"

    40 and 80 meters the effort to install 1/4 wave vertical elements (33 and 66 or so ft) would be the way I go.

    Rege
     
    NH7RO likes this.
  4. K9STH

    K9STH Ham Member QRZ Page

    I have 2-each full sized verticals that I phase 90-degrees on 40-meters. The apparent gain, verified with well calibrated "S" meters and using an attenuator with 1 dB steps, is more like 4.5 dB in the forward direction, about 3 dB at 90-degrees to the forward direction (on both sides) and a little over -20 dB off the back.

    These verticals are about 35-feet apart for "quarter-wave" spacing. I do have the ability to "flip" the pattern 180-degrees as well as the ability to use each vertical as an independent antenna. The gain measurements were made when foreign broadcast stations were still allowed in the 7100 kHz to 7200 kHz segment since the signal strength was constant for a few minutes while the measurements were taken. Fortunately, at the time, there were enough stations located close to the calculated directions for maximum gain and at 90-degrees to each side. The "null" was measured "flipping" the pattern.

    Because of the "layout" of my backyard, maximum gain is towards Japan when phased to the northwest and towards South America when phased to the southeast. No matter which way the antennas are phased, I still have around 3 dB gain to Europe and Oceania.

    From the Dallas, Texas, area, during the winter months when the noise level is generally lowest, I have started working JA (Japanese) stations before midnight local time and have still been working them after noon, local time, the next day. I do have the QSL cards to confirm this! The latest SSB contact was going on noon local time and the latest CW contact was about 1:30 PM local time! Some portion of Europe can be worked at least 16-hours a day and, during DX contests, when there is activity for 24 hour periods, stations can often be worked for the entire 24 hour period.

    I do live 1/2-block from the highest point in the City of Richardson, Texas, and it is downhill for over 300-degrees and uphill, for about 10-feet and then downhill for the remaining about 60-degrees. That definitely helps with the angle of radiation from the phased verticals.

    Of course, on 20-meters and higher bands, Yagi antennas generally do work better than phased verticals. However, if your only viable antenna is a vertical on 20-meters, then phasing can definitely help with your signal strength. It also is very helpful if you can alter the phasing so that the pattern can be varied.

    Glen, K9STH
     
  5. N7WR

    N7WR Subscriber QRZ Page

    Many years ago I was trying to finish DXCC on 40 meters (SSB) from my qth in the mountains of Northern CA. I had a single 40 meter monoband home brew vertical, elevated, with 4 sloping radials. It worked fine but I needed a bit more gain to work the many European countries that would put me over the 100 mark. I built a second, identical antenna and using info from the antenna handbook regarding spacing, construction of phazing harness, etc I made them end fire towards Europe. It was a killer antenna for EU and AF and finishing DXCC was relatively easy. I later did the same thing with a pair of homebrew 80 meter verticals also with positive results
     
  6. N4UP

    N4UP Premium Subscriber QRZ Page

    Just wondering how you do radials for two or more phased verticals. Do you have independent radial fields or are they coupled in some way?
     
  7. K9STH

    K9STH Ham Member QRZ Page

    My radials are elevated although only between 2 and 6-feet above ground. They are independent. That is, none of the radials are connected to another except at the end at the base of the antenna.

    Until my swimming pool was installed, I had about 48 buried radials under my HyTower. Then, a good part of the buried radials were dug up when the yard was "cut down" and then the hole dug for the swimming pool. The "other" 40-meter vertical was installed several years after the swimming pool (the pool has been "in" for a little over 35-years).

    Experiments on the AM broadcast band at 600 kHz, 1100 Khz, and around 1600 kHz showed that 4-each quarter-wave radials 6-feet above ground worked about as well as 120-buried radials. In terms of wavelength, 6-feet at 600 kHz equates to 2-feet at 1800 kHz (160-meters).

    My 40-meter radials run along the retaining wall for the pool, at various heights along my wood stockade fence, and along the slab of my house. The HyTower works better with the elevated radials (4 cut for 80-meters, 4 cut for 40-meters, and 4 random length) than it did with the 48 buried radials. Under the 40-meter (actually there is a "stub" for the 30-meter band on the vertical) vertical there are 5-radials that run in various directions. Why 5 instead of 4? I had some wire left over so I ran a 5th radial!

    Glen, K9STH
     
  8. KM4ZCT

    KM4ZCT XML Subscriber QRZ Page

    The slope of my backyard from the current antenna to the position where I would place the second antenna is around 25 degrees.

    Thank you for the detailed reply! Currently on my vertical I have about 70 radials laid down. I'm looking to try and contact stations in Europe and Asia/Pacific, and out West maybe to finish WAS. Would 20m or 40m be my best bet when phased? I'm thinking 20m might be better due to the times I can get on my radio. Would this be covered in the ARRL Antenna Handbook?
     
  9. K7JEM

    K7JEM Ham Member QRZ Page

    I helped a friend build an "8 circle" array for 160M a few years ago. He ran the radials outward to where they intersected with the next tower, then ran a wire down that line, then soldered each radial to the wire "runner". I think he had 32 radials on each QW antenna, so lots of wire laying on the ground.
     
  10. N4UP

    N4UP Premium Subscriber QRZ Page

    Thanks K9STH and K7JEM. I wish I had thought of phased verticals when I installed my 8040 vertical ( with 64 x 65' buried radials ) and 160m inverted L ( with 76 x 130' buried radials ). Now I have to think how best to add additional verticals. I have 15 acres of woods to play with, but with two verticals in the woods and two 900-1000 foot beverages about to be installed in the woods, I have to be careful where I put TX antennas.

    And thanks KM4ZCT for the asking the original question.
     

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