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@ -21,9 +21,9 @@ So with all the RF kept outside and under tight control, the system only needs p
### Mechanical
The antenna casing that you see in these photos is a piece of 1" Schedule 40 "furniture" grade PVC pipe. It is simply the most inexpensive UV resistant material available, and it looks great too!
The VHF antenna whip is built using an epoxy wound filament tube coated with high grade US-made irradiated polyolefin ("heat shrink") tubing. The company that makes this tubing (and helped me with this design challenge) also built the landing gear for NASA's Ingenuity helicopter, currently flying on Mars. They definitely understand how to deal with harsh environments. The bottomline is that unlike typical fiberglass antenna masts you might see around (or have on your boat already), this antenna is not going to degrade and "blossom" under continuous sun exposure.
The VHF antenna whip is built using an epoxy wound filament tube coated with high grade US-made irradiated polyolefin ("heat shrink") tubing. The company that makes this tubing (and helped me with this design challenge) also built the landing gear for NASA's Ingenuity helicopter on Mars - they definitely understand how to deal with harsh environments. The bottomline is that unlike typical fiberglass antenna masts you might see around (or have on your boat already), this antenna is not going to degrade and "blossom" under continuous sun exposure.
The entire outdoor assembly is held together by the same high grade heat shrink tubing. The main water seal is formed by heat shrinking the tube around a specially designed 3D printed cap made of PLA. This part naturally softens when heated, and because it is compressed by the heat shrink tubing, it forms a permanent, tight colar around the antenna tube. A layer of clear heat shrink in the interior forms a secondary water seal encompassing the lower part of the antenna.
The entire outdoor assembly is held together by the same high grade heat shrink tubing - there are no messy adhesives to deal with. The main water seal is formed by heat shrinking the tube around a specially designed 3D printed cap made of PLA. This part naturally softens when heated, and because it is compressed by the heat shrink tubing, it forms a permanent, watertight colar around the antenna tube. A layer of clear heat shrink in the interior forms a secondary water seal encompassing the lower part of the antenna. PCBs can be coated with either silicon or acrylic conformal coating for an added layer of protection.
The unit can be opened and serviced by (carefully) cutting through the heat shrink tubing with a knife, then resealing with the same material and method as before.