Protect your Cloverleaf antenna

by apache64 | March 14, 2013 | (9) Posted in Tips

Whilst i was getting ready for the better spring weather i built a newer Cloverleaf Antenna for my hopeful FPV flights, once the weather is better. It was during the building i realised how fragile the Antenna could be, if you have made it out of thin wire or even soft copper wire.

I then thought i would try an idea i saw on a post many months ago which i unfortunately have lost the link to where someone had put a ping pong ball over the Antenna. This seemed not to difficult and so below is my step by step walk through of how i built my Antenna cover.



First find you new or in my case squashed ping pong ball.


 Cut the ping pong ball along the join , i used a Razor saw which did little damage to it.



 Drill a hole in the middle, i then shaped it square as my Antenna was square at its base, then split it to the edge of the ball.


 Slip the ball over the antenna using the split to slip it on from, the ball is vert flexable and wont tear.


 Then using either the other half of the ball or, again in my case a second squashed ball you can mate it with the first half.


 I then used a little Epoxy to glue the ball in place, and used some more to seal the split that i made to get the ball onto the antenna.

 The finished product, it looks ok, but could be painted to make it look more dramatic, say Orange :-)

I just wrote on it TX to remind me it is a Transmitter antenna as i no longer can see it :-)



Klaus on March 16, 2013
It doesn't really distort the frequency or accuracy of the antenna, it just shifts the resonant or operating frequency of the antenna down a bit. In your case the plastic is so thin that the effect may well be negligible, I just don't know.

The effect is related to the dielectric constant of the plastic, for which you can find tables on the web. You may run across dielectric loaded antennas to make them physically smaller at a given frequency but those are embedded in the dielectric.

I say if you are satisfied with its performance, it's good!
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apache64 on March 16, 2013
Hi Exot, a beach ball would be to soft, but you could inflate a ballon over it and this would act like a air bag??
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Klaus on March 15, 2013
Cool idea!
However, when you put an antenna in any type of dielectric enclosure it becomes electrically larger. Some years ago when I was making VHF and UHF antennas I'd have to make them about 20% smaller if I put them in PVC tubing than if I didn't. I don't know how much effect a thin ping-pong ball would have though. A SWR bridge for 5.8GHz is not cheap or easy to make.
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exot on March 16, 2013
Nice! 'll try it with an 900Mhz Cloverleaf and a beach ball!
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apache64 on March 16, 2013
Hi Klaus, i never knew that, so i guess this will distort the frequency and accuracy of the antenna? any info on which materials are worse than others?
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Protect your Cloverleaf antenna