Simple PVC pipe relay enclosures for field operations

#1

I have put together some simple encloures with the following goals.

Cheap
Easy to assemble
Parts readily available
No modification to the goTenna
Not a 24/7 solution, intended for single day events

Parts needed.

  • 5" length of 1-1/2 PVC pipe
  • 1 PVC end cap
  • 1 eyebolt
  • 2 hex nuts
  • 1 1-1/2" temporary pipe plug (Oatey “Gripper”)
  • PVC primer and cement
  • Silicone sealant
  • Spray paint of your choice

Seal the top from water both outside and inside with some silicone. I did this before cementing the pipe to the cap.


Let the Assembly cure.

Insert powered on goTenna.

Cap off the bottom

using your favorite rope, hang unit from a convenient tree, or other high object.

2019.03.02: update
Pictures with it in a tree before and after painting.

Before
IMG_3188

After
IMG_3191

It in the shadows.

9 Likes
#2

That’s a nice, easy to make setup. Thanks for sharing!

1 Like
#3

I would make it with the thinnest pvc pipe, to make sure you are not blocking the rf on tx and rx.

#4

PVC generally won’t block RF. It may slightly shift the center freq, but this is a minor effect and seems to be an issue mostly above 1 gHz (the 900 mHz ISM band that GTM uses is below 1 gHz.)

Some PVC has metal fillers and would have a larger effect, so should be avoided.

A useful discussion on this is at: http://forums.radioreference.com/threads/will-pvc-pipe-block-signal.252888/

I actually kind of like the greater mass/density of this versus my Firefly design for improvised nodes. The plastic fruit jar that is used in that is rather light and the overall item is pretty light. The PVC design makes for a higher density in a slimmer container, so should work a little better at penetrating foilage and not getting hung up when you sling it into a tree.

#5

Thanks @MikeL. I rather doubt there is an impact on coverage. Funny I looked at the link you referenced a while back when i was making a 70cm antenna. :slight_smile:

I will try and run some very unscientific tests tomorrow and see if there is a noticeable difference in coverage.

Regarding foliage etc… What I did, and plan on doing to get it up a tree is to use a “rock bag” to get the rope in the tree and swap out the bag for the enclosure and hoist it back up. Even better if you think you will be raising and lowering several times would be to attach a pulley to the end of the support rope after using the rock to get it in the tree and then hoist the enclosure on a second rope going through the pulley limiting the friction of the rope over the tree branch. Also using a rock, one avoids throwing electronics through the air ready to smash into something.

1 Like
#6

I think the Pelican-like Harbor Freight cases I use to house the UMESH nodes in are PVC (or something very similar.) There seems to be little if any issue with RF attenuation with them. The wall thickness is approximately equal to or perhaps a little thicker than plastic pipe.

Just to be clear, I’m certain there is some minimal effect on the signal. However, it is so small it can be ignored for our practical purposes.

1 Like
#7

I agree. I would just post “Agreed” but the system is telling me I have to have >20 characters. ok box checked.

1 Like
#8

I did some tests in my neighborhood. the change in coverage was negligible across several tests.

The “mobile” GoTenna" was mounted near my shoulder as I walked through my neighborhood. Pinging the fixed unit every 10 paces.
The fixed GoTenna in the following arrangements all 7’ off the ground clear of local obstructions.

  1. Stock GoTenna.
  2. GoTenna enclosed in PVC container.
  3. GoTenna enclosed in PVC container painted with Krylon camouflage spray paint.
2 Likes