Antenna

The new 107-ft (32.6m) EFRW in the backyard is doing OK, and I’m getting pretty lucky with low power on 10M FT8.

• Japan (10500 km): 5W, 2025-02-10 2245 UTC
• Norfolk Island (14000 km): 2W, 2025-02-11 2238 UTC

I was using the 71-foot (21.64m) EFRW antenna at home, and I noticed SWR was surprisingly low as measured by the X6100 with the tuner disabled. I suspected loss on the feed line, but I also found this video of another person not using a tuner with the same antenna.

I disconnected my feed line at different places to find SWR jumps way high, so the measurement is working:

• inside window
• outside window
• at the antenna

Does a very long wire have low SWR for everything? Is the 9:1 giving low SWR? The antenna’s working fine, and FT8 shows far-flung signals like always. Disconnecting antenna wire raised SWR above 1.5:1, but not much. Even with wires disconnected from the balun, it’s receiving a very few FT8 signals on 10m, and I can still transmit, but it’s folding back power with SWR just below 2. The tuner is definitely needed for 6m.

The 1/4-wave ground plane antenna in the tree dropped its feedline, so I brought it down to reattach it and resolder the radials.

I also walked down the yagi on the pole to straighten some elements, since it was a nice day. The yagi was spinning around in the wind, so I also changed the way it’s mounted to clamp it more securely.

I also added some reigns to the mast, so I can (try to) spin it from inside the window. It works well some times but not others. The pole can freeze to the ground.

I watched a video about NVIS NVIS achieves 75-90 degree take-off, very vertical, and about a 400-mile range. It can get you over obstacles. It’s most effective on 40m and 80m.

To build it, mount a dipole 1/8 wavelength above ground, horizontal. Add a reflector almost on the ground, 5% longer, to keep the ground from absorbing the signal.

My Week in Radio

Contesting

I finished the FT Challenge. There was no special exchange this year. We could use other defined subbands in addition to the regular frequencies to alleviate crowding. We could work anyone, even if they’re not participating explicitly.

I operated QRP, so it was nice to find the quieter subbands and more FT4 activity. You earned multipliers for each 3000km, so I don’t really know on my score yet.

I found wsjtx-improved on the Debian Linux repository, so used that. I saw the color improvements, the better location labels with states, and it had filters.

AllStar

I learning some obvious things about AllStar: it can’t hear my DTMF if it’s currently transmitting, since it’s simplex, so it’s hard to control on a busy net.

Yagi in the Wind

Finally, I watched my home-built yagi flapping around on that windy day. I guess I can stop worrying about it, since it held up fine.

The home-brew yagi blows around in the wind a bit, so I brought it down this morning as it started to snow, so I could straighten and tighten the elements. I realigned it for the 985 repeater, and checked it to be giving -96dBm.

I also resoldered some radials on the 1/4-wave ground plane antenna that go knocked loose in the tree.

I added some sections to the flag pole to reach 37 feet, and I increased elements on the home-made yagi from 2 elements to 4 elements. Upon adding elements, I needed to stretch the driven element a couple millimeters longer to tune it. In testing, I’m seeing about -100 RSSI listening to W3GMS on a Quansheng. It was about -105 RSSI when mounted lower and only 2 elements.

Tilt-up Flag Pole

I figured out to do a tilt-up flag pole against the house reaching 25 feet into the air. It sits on a stake in the garden, and is secured to the house with paracord in an eyelet and hook screwed into the side of the roof.

2-Element Yagi

I built a new 2-element yagi using an online calculator It tuned OK with the banana-clip adapter directly connected to the driven element. I first tuned the dipole, and then added the reflector element. As predicted, it shifted the tuning slightly, so I trimmed the driven element to retune. The nice thing is that the spacings and sizes of the original elements don’t change as you add more director elements, so I calculated it with 2 or 3 directors, but put none in for the first iteration. I can add more elements later.

I gave it a try to reach 985 with the TYT TH-9800 running 50W. It was scratchy, but copy-able. I have more flag pole sections ordered to make it a little higher.

Prime Day popped up a few good-enough sales, so I bought a few things.

• 50w dummy load
• TIDradio TD-H8 - HT, 10W, bluetooth, clear case, etc
• TYT TH-UV8000D - HT, 10W, crossband repeater
  • This should allow me to crossband relay to a repeater via the outside antenna and wander the house with a smaller HT
• BNC adapters for HTs.
  • Everything goes to BNC for easy swapping to external antennas.
• 4 HSY Telescoping VHF/UHF antennas with BNC connectors for HTs
• TinySA
• Sony headphones, wired, as backup for the ones I use now for POTA
• 2 Pi Zero W kits with cases, connectors, and all that
• 375ft of micro cord for throwing antennas into trees

My 12.5m EFRW at home broke again, so I needed to restring it. The wire breaks at the tie point up in the tree. The kids and I failed to launch it again over the tree with slingshot out the window. I had also tried some small 3d-printed s-biner clips, but they’d release as soon as I launched with the slingshot I got the wire running flat through the other tree instead of up and over.

That didn’t last too long. The wire broke again at the tie point, so I launched it from the street again with the throw line and sockets. I kept it a little looser and switched to a bungee cord to keep it tensioned with some play.