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.
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.
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.
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.
There are easy instructions to build your own yagi on Instructables. I had just picked up some hose clamps and had the other necessary pieces: a broken tape measure and some 3/4-inch schedule 40 PVC and connectors; so I was ready to build.
The wiring on mine is held in place by the clamps and banana clip adapter. I always like those for prototyping. As directed, I tuned the antenna by moving radiators in and out and measuring with the NanoVNA.
The antenna is noticeably directional, so I can use it to find directions of signals. The S-meter and dB signal strength numbers on AUBS firmware make it easy to evaluate strength and direction.
I transmitted with it to the K3IR repeater as a test during a net.
The one-page document that comes with the GRA-1900T antenna detailing the jumper positions on the coil and the lengths at which to set the whip for each band didn’t seem to match up all that well, which led to some frustration out in the field.
I decided to use my NanoVNA to reconstruct my own instructions for using the antenna. I extended the whip fully and recorded the resonant frequency for each jumper position of the coil. Knowing those frequencies, I can set the jumper and shorten the whip until the SWR sweep on my x6100 is happy. The SWR graph on the x6100 can be misleading sometimes, because it often shows a birdie dip or 2 in the graph, but now I’ll always know that I’m to shorten the whip to get where I need to be.
I’ll eventually apply labels to the coil with these frequencies.
I took the GRA-1900T out to Susquehannock State Park for a field test. My plan to tune the antenna worked well. I set the jumper for the frequency below my intended operating frequency and shortened up the whip until the x6100 showed a good SWR curve. Easy!
Since I hadn’t used the fishing pole at the park, I forget I had it and left it behind when I packed up. 2 days later, I returned to retrieve it. Some kids had found it, had trouble collapsing it, dug in the dirt with it, and broke a section.
I was able to put it back together with the remaining sections, and I 3d-printed a new fork/loop to make it useful for supporting wire.
My antenna wires at the house were getting moved around a bit with some projects. I found my SWR was a bit high on a certain HF band, and I found moving or coiling the counterpoise (~5.2M) to shorten it greatly reduced SWR. I have to remember to watch performance and adjust the counterpoise as part of my setup and operating.
I removed the magnet from the inexpensive mag-mount antenna that I had stuck to a baking sheet in the back of the BMW i3 (which is all plastic). The bike rack is always on the car, so I cobbled together some scrap metal parts and clamped the antenna onto the rack. It’s got a screw knob, so I can loosen and reorient it when I flip the bike rack.
It works great now with the antenna outside the car and attached to the metal of the rack.
I Tested my 20m EFHW wire and unun on 2 different POTA outings In an inverted v with a counterpoise, it worked pretty well, but could be shortened. As a vertical, the SWR was higher, and the counterpoise made it worse. I compared the vertical EFHW to the trusty old EFRW in a mostly vertical configuration. That one had exhibited a terrible SWR as well with or without counterpoise. Maybe I needed more radials instead of a counterpoise? I have 2 ARRL antenna books, basic and the big one, so I could read, I suppose. During these experiments, my computer experienced some common-mode interference too.
I 3D-printed a nice customized winder with the transformer attached. I modified the code to be parameterized to any size I want.
I’ve been discovering I can hear some further repeaters using the spectrum analyzer feature on my Quansheng, so I’ve been adding more repeaters to the scan.
