Revisiting Phased 80 Meter Verticals
N4JTE
As most of us these days, I have a lot of free time. I decided to revisit 80 meter phased reversable verticals with potential 3db of gain East or west.
Seemed like a fairly easy project as I had done it before and the concrete embedded 4x4 posts were still available at 60 foot spacing. Problem was my 60ft spider poles were in sad disrepair so I investigated the concept of using my trusty available trees to support the 60ft vertical insulated wires.
I have had amazing results with phased dipoles on 40, 20 and 15 meters but alas, my 80-meter dipole maple tree was cut down by the town and is now heating my house!
In order to getter done I would need to get 2 insulated 16 gauge wires up to 60 ft high into trees approximately 1/4wl apart. After some due diligence on tree limb attenuation I endeavored to reach a branch far as possible from the trunk.

CONSTRUCTION:
When I ventured into the Christman phasing approach many years ago I helped develop a plug-in online calculator to establish accurate physical phase line lengths based on frequencies needed to match phase/lag line. Available by google VA7ST christman calculator;
http://www.va7st.ca/christman.htm


As displayed in photo, hopefully, my center frequency is 3.800 mhz. The table shows the 71-degree feedline with an approximate length of 33.691 ft at .66 velocity. However, I cut my rg8x at 38ft. Then I hooked it up to my RS swr meter with a tee coax with one connector to dummy load and other to test coax. As noted, my frequency for 71 degrees is 4.817. I tuned for the lowest swr point, my freq ended up at 4.2 mhz, too long, so I continued to cut and measure till reaching 4.817. This method requires tested lines to have ends shorted together. This line is the lag line for direction switching and will be soldered to the 2 relay rear terminals along with, in my case, the West and East 84-degree lines. FYI, I long ago cut the diode on 751a for open transmit for these kinds of testing.
The two 84-degree lines are around 40ft so I started at 45ft and looked for lowest swr at 4.071. My QRZ page shows the relay wiring with good clarity. https://www.qrz.com/ N4JTE
If the table is lost in post editing or difficult to read try Google for va7st christman calculator or text me at 845 665 5544 with desired centered frequency and I will text back the target frequencies and starting length for coax lines.
I tested all 3 RG58 lines even though the two 84-degree feedlines should be of equal length but you never know! Look for the strongest dip while tuning the radio vfo up and down while driving with 10 watts or so, don’t expect zero impedance just the lowest relative display. A more expensive swr meter or analyzer not needed.
BACKYARD:
It took some time with the fishing pole to get the EAST and WEST, 16 gauge insulated green wire at the best location in the trees. I used the 20lb fishing line to pull up the 60 ft. of wire and had maybe a foot or two that were flatopped. I put a wood stake in the ground and zip tied off the verticals. Two 60ft radials were attached to each stake 90 degrees apart and raised up over available trees on both verticals. Snaked them all thru trees then on 6ft wood fences,
Checking things in the shack I turned on radio after hooking up 75ft of RG58x to antenna switch hoping for something. Whew the band was noisy as usual at 3pm here but noise is a signal! I hooked up the 12v lines to a RS 3amp power supply which I switch thru a desk mounted light switch with switch on ground lead. Set radio to rtty and threw out 30 watts and checked swr both directions, switch working and west is 1.5 to one and east is 2.0 to one, fantastic, means the relay and directionality works!! I found a happy medium on the LDG auto tuner and started exploring the band.
Whoo hoo! at 4pm I heard a CT. group on and butted in of course and received a 4 s unit difference when direction switched. Cannot wait for dark.
Yep it is a winner, won’t belabor the 79 contacts made on 80 during the WPX contest but thrilled with the results! I am well aware that the big contest stations were doing most of the heavy lifting but working Indonesia was a trip. Spent next few hours working stateside stations on the Omiss net where the East rejection made it possible to work thru contest.
CONCLUSIONS:
1: Not sure what attenuation the future leaves will bring but I own a nice 14ft Stihl trimmer, hi.
2: Was not my intention to build a stealth antenna but this baby is invisible, no worries about wind or nosy neighbors this time.
3: This concept is valid for any band with verticals or dipoles.
4: Total cost minus feedline less than $50.
Perfect doable project for my 71 years, lot easier than 60ft towers.
Be safe all and tnx for reading.
N4JTE
| W4VR | 2020-08-07 | |
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| Revisiting Phased 80 Meter Verticals | ||
| thanks Bob. Great article. Keep up the good work! | ||
| N4PIE | 2020-07-18 | |
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| Revisiting Phased 80 Meter Verticals | ||
| This is an interesting concept. I am not sure I have the room to pull it off where I live. But it certainly gets the old brain thinking about possibilities. I look forward to reading more of your stuff, Bob. | ||
| WX7Q | 2020-07-01 | |
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| Revisiting Phased 80 Meter Verticals | ||
| Thanks for posting. I am limited to using verticals. Have always been interested in phased antennas. Jim WX7Q | ||
| N4JTE | 2020-06-03 | |
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| Revisiting Phased 80 Meter Verticals | ||
| Is thing working? lol | ||