DIY Radome?

[JERRY TAYLOR]

I am completing a portable system (yagi on telescope tripod, raspberry pi 4, battery operation) that I hope to operate for extended periods remotely.  I need to provide protection from the elements and was wondering if a small pvc pipe frame with heat shrink wrap covering would work without degrading the hydrogen signal.  Has anyone built a simple radome?   What kind of problems might I encounter?  Heat, condensation, etc.?

Jerry Taylor

[Marcus D. Leech]

On 14/07/2024 14:07, JERRY TAYLOR wrote:

I am completing a portable system (yagi on telescope tripod, raspberry pi 4, battery operation) that I hope to operate for extended periods remotely.  I need to provide protection from the elements and was wondering if a small pvc pipe frame with heat shrink wrap covering would work without degrading the hydrogen signal.  Has anyone built a simple radome?   What kind of problems might I encounter?  Heat, condensation, etc.?

Jerry Taylor

Heat and condensation would be the big ones.   The shrink-wrap that's used for boats is typically a modified LDPE, and
  should be fine at 21cm frequencies.  Will there be some loss?  Yes.  But it will be quite small.

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[JERRY TAYLOR]

Maybe a bucket of Damp Rid for condensation and white LDPE shrink wrap?

The area would be small, maybe 50cu ft.

Jerry

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[bsn...@gmail.com]

Greetings...

Have you considered Tyvek?

Water-proof but breathable. I have no idea of its electrical properties but I'm sure DuPont does and others as well.

A search on: Tyvek electrical properties turned up a lot of info.

....GL......bill.....

[JERRY TAYLOR]

Tube sounds like a good idea.  I will check it out.

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[Marcus D. Leech]

On 14/07/2024 16:16, bsn...@gmail.com wrote:

Greetings...

Have you considered Tyvek?

Water-proof but breathable. I have no idea of its electrical properties but I'm sure DuPont does and others as well.

A search on: Tyvek electrical properties turned up a lot of info.

....GL......bill.....

Would certainly be more robust than shrink-wrap.

Genuine Tyvek(tm) is a woven HDPE material, so similar loss tangent to LDPE and PTFE.  Avoid anything made with
  PVC--the PVC molecule is polar, which makes it quite a bit more lossy than PE or PTFE materials (by a factor of 50 to
  90!!!!!).

Your PVC support members will be fine, since nearly all of the energy is propagating through the membrane, and
  not the support structure.  Keep the support members as thin as practical, given the mechanical constraints.

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[JERRY TAYLOR]

I just checked and I have a large roll of polyethylene 4mil painters plastic.  Won’t shrink or last as long as Tyvek.  Should this be rf transparent?

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[Marcus D. Leech]

On 14/07/2024 16:36, JERRY TAYLOR wrote:

I just checked and I have a large roll of polyethylene 4mil painters plastic.  Won’t shrink or last as long as Tyvek.  Should this be rf transparent?

As long as it's actually polyethylene.  There are also PVC painters drop-clothes, and they wouldn't be suitable.

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[bsn...@gmail.com]

If you do decide to use Tyvek not sure how you would attach it to your plastic pipe frame.

When used in house construction in is always stapled to either the wooden underlayment of the roof or the wood sheathing on the walls.

It is remarkably resistant to winds. 

Most Tyvek I've seen is white, a decent reflective sufrace. Howerver, I've recently seen canary yellow and blue and pink!

Again, GL.....bill....

[Alex P]

Use a Leg to cover the Yagi ....

[Lester Veenstra]

To repeat a very old hoarse:  Put in microwave. If it heats up it is not rf transparent

 

Lester B Veenstra  K1YCM  MØYCM  W8YCM   6Y6Y W8YCM/6Y 6Y8LV (Reformed USNSG CTM1)

les...@veenstras.com

 

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[JERRY TAYLOR]

Good idea Alex!  Two for the price of one also.  Maybe four?

Jerry

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