Wire antenna messenger line hanger
Obliczymy ostateczną cenę na podstawie wybranego pliku. Sprawdzisz ją i zaakceptujesz przed płatnością.
Zapisane na tym urządzeniu.
This thing lets you hang a wire antenna from a messenger line without knots or free ends. Parametric and simple.
- Ocena
- 0 / 5
- Polubienia
- 1
- Pobrania
- 14
- Wydruki
- 0
- Wyświetlenia
- 50
- Oceny
- 0
Aktualizacja u źródła:
Informacje o modelu
- Źródło
- Printables
- Kategoria
- Electronics
- Licencja
- Creative Commons — Attribution — Share Alike
I didn't know what to call this when I first started looking for one. Here are some keywords I tried, so it comes up in the next person's search: wire hanger, line connector, fan dipole spacer, split ring, keychain, keyring.
Wire dipoles hung from trees are my jam. For permanent installations, I like to use a messenger line, which is a structural rope used to support the wire. Using a messenger enables you to use much lighter wire, which keeps the overall weight of the antenna down and reduces issues with the trees and wind.
Putting knots in the messenger line gets pretty fiddly, so I made this thing to more easily attach the wire. You'll need one every dozen feet or so along your antenna.
Parameterization
I designed this in FreeCAD 1.0.1, entirely using the Part Design workbench. It has a "VarSet" (variable set) object, which allows you to edit the gauge and gap.
Gauge is the thickness of the plastic parts. The default value is 3.5mm. If I went any smaller, I had bed adhesion issues (PETG, MK4S, textured bed).
Gap is the spacing between the spirals. 26-gauge wire works well with a 1mm gap. Remember, the plastic is flexible.
Printing
You probably want PETG or better, since it'll be outdoors. Read the above note regarding bed adhesion when gauge is set small. No supports are required. Make sure to print with the flat side down, not the rounded side.
Usage
This assumes you have already laid out a messenger line, either on the ground or hanging low where you can reach it. Attach the feedpoint of your wire antenna as you see fit. Then attach a few of these hangers. For each, you will:
FIRST pull a bight of messenger through the hole, and pass the hanger through it. The result is a girth hitch. You must do this step first. It is possible to allow the girth hitch to close on the midsection of the hanger; I recommend you pass the hanger entirely through the hitch as pictured. The result will be static on the messenger line.
THEN push the wire into the spiral, like a keychain, until it is captive in the central opening. The wire will be free to slide along the hanger as needed. This is important to avoid breaking under wind and tree movement.
Finally, secure the end of the antenna. I use shock cord for mine. I've seen people use springs, but these require an insulator.