Vertical Antenna

In a former life at this QTH, I had a nice 130-ft Carolina Windom up about 50 feet or so. When the halyard was cut at one tree, I couldn’t replace it. My temporary kludge was a pathetic long wire pulled up 50 feet in one of those trees and then draped over some bushes 70 feet away. It sort-of worked, but did a whole lot better when I put a remote tuner out at the base of the tree.

Temporary can lead to permanent, so I decided to do a proper antenna … now, before I got too used to the long-wire lash-up. Time to try a vertical on my hilltop.

The vertical is a DX Engineering DXE-MBVE-1 multi-band 160-10 meters. It’s a non-resonant 43-foot tilt-over mounted on a 2″ pipe set in concrete. The radial plate from DXE has 16 radials connected to it (14 are 32′ and 2 are 25′ long – the spool was 500′ ). At the base, I put down a number of patio pavers to make a stone mount for the tuner, the MFJ-993BRT. Buryflex low-loss coax (about 127′) with RF chokes (COM-RFB-160 from DXEng) heads for the house.

Results: The remote tuner gets the SWR down to around 1.1 to 1 on most bands 80-10 meters. 15 m is around 1.7:1 and 30 m is about 2.4:1 (I don’t know why, but I don’t use that band much.)

Aside: I always completely disconnect the coax from my Elecraft K3 when I’m not on the air.

—–> Thoughts on construction follow the photo gallery. <—–

Some thoughts on the construction:

  • It would have been easier if I had run the trencher before I stretched out the radials. (I bought that edger after I got totally fussed trying to dig into the rocks!)
  • Several of the radials aren’t buried, but are marked with bright red “caution” tape. The trencher didn’t work too well with leaves in the way, and after hundreds of feet of trenching, I marked the radials so I wouldn’t trip over them. Maybe they’ll get buried in leaves and be as good as under all the rocks. One would hope.
  • I had already tried the remote tuner on the long wire antenna, and was somewhat surprised that it failed to tune the vertical. When it tried to tune, the SWR was all over the scale, and I concluded that the coax was acting like a radial: it needed an RF choke. So, to verify that assessment, I coiled up the extra coax tightly at the base;  the tuner tuned up many bands then. I got the choke kit from DXEngr and put them on the coax (see photo). Unfortunately, somebody didn’t do their homework: the heat-shrink tubing that was to slip over the chokes was too small. Ah, well.
  • Rather than a lot of heroics sealing all the remote tuner connections, I took the easy way out: cover it with a plastic box.
  • The weather took a turn colder within days of completing the project. The antenna would NOT tune up … it acted the same as it did before without the chokes! MFJ told me to do a hard reset of the tuner, and that meant bringing it inside and removing the cover. Once it was open, I saw immediately that the wire from the tuner PCB was not soldered to the antenna solder lug. The wire was touching lightly enough to work when it was warm outside, but contracted when cold and broke the connection. After properly soldering the connection, it’s been working fine.
  • The coax runs along the ground (I didn’t bother burying it) directly to the shepherd’s hook in the first photo. It goes over the hook, across the sun-room roof, through the gable at the end of the house, through a hole in attic floor into a closet, and finally out of the closet to my Elecraft K3 on the second floor.

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