Jump to content
Sign in to follow this  
Mr.RC-Cam

Poor Man's 5.8GHz Ping-Pong Ball Radome

Recommended Posts

5.8GHz circular polarized skew planar wheel antennas are a fantastic upgrade for FPV applications. A quick search with Google will reveal several published articles (and videos) on how to make 3 lobe and 4 lobe versions for less than $5 each. For example: http://www.rcgroups.com/forums/showthread.php?t=1388264

These 5.8GHz skew planar's are small enough to fit inside a ping pong ball. Let's just call it a poor man's radome. I'm certainly not the first to think of using a ping pong ball to do this, but given all the DiY antenna building that is going on I am very surprised that I haven't seen examples of it. Perhaps it's because a bare naked skew planar wheel antenna looks techie and cool.

But I was curious to see an example of the DiY ping pong ball radome hack. So that means I had to just do it. I used a commercially made 3-lobe "Cloverleaf" antenna but the 4-lobe fits fine too. This particular antenna's SMA connector is mounted directly to the elements, but keep in mind that some antenna build variations have a short coax extension. So mounting the ping pong ball will vary.

Here's a quick run-through (10 minute build time, no attempt to be neat and tidy):

1. Cut the ping pong ball in half. I paid $1 for a pack of 8 balls (16 radomes!). Cheap balls are a good choice because they have a visible seam to help direct your knife.

2. Cut some 15 mil (0.38mm) PVC sheet plastic to fit the diameter of the dissected ball.

3. Cut a hole in the center of the PVC disc to fit snuggly around the antenna connector or coax.

Here's what you will have at this point:

post-2-0-72840000-1372206318_thumb.jpg

Share this post


Link to post
Share on other sites

Install the circular disc on the SMA (or coax) using a small amount of hot melt adhesive. Do NOT use big blobs of adhesive since it's proximity to the lobes (elements) can affect the antenna's tuning. Here's the half-way point in the build:

post-2-0-20251700-1372206956_thumb.jpg

Share this post


Link to post
Share on other sites

Finish up by gluing the ping pong ball to the disc. I used little dabs of hot melt around the perimeter. Do not use too much and place it in spots that are furthest from the elements. After the adhesive cools you will have a radome that is rigid and strong.

Here's the finished poor man's radome:

post-2-0-50379000-1372207126_thumb.jpg

BTW, if you are a serious SWR fanatic then be sure to measure the antenna after installing it in the radome. The plastic's dielectric properties can have a minor impact and so measurements are best done with the final build.

Share this post


Link to post
Share on other sites

haha, I was thinking using the ping pong ball too. Only mine is yellow. ;) Now i know it does fit.

by the way, the registration is confusing. I answered the question :

"which language is spoken in the united states/"

A: 150 of them according to ObamaCare

and it was rejected. hmmm :) :)

and the balidation numbers, when I click on 'voice/spker', it pronounce some really odd sound almost inaudible. ;)

Share this post


Link to post
Share on other sites

I agree, the spoken re-CAPTCHA is very strange sounding. It is often compared to hearing a room full of people speaking some alien language. Most sites (including rc-cam) use essentially the same re-CAPTCHA voice engine. To hear the aliens talk just try the re-CAPTCHA tool found here:

http://www.google.com/recaptcha/learnmore.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  

×