The BucketWhip 70cm Groundplane Vertical

 

I needed a quick and dirty vertical to test the ATV setup in the bucket bot. I've spent some time coming up with clever omnidirectional circularly polarized antennas, but I wanted something easier; i.e. construction time<5 minutes. What I did was stick a BNC connector through the bottom of the bucket. A 17 cm long piece of bare AWG#12 copper wire was soldered to the center contact (after filing the end of the wire down so that it would fit in the solder cup. The ground plane was 4 pieces of 1" copper foil tape stuck to the base of the bucket in a cross.

(54 KB jpg) or click the thumbnail

bucket whip thumbnail 4K

It works, after a fashion. The real problem is that the whip isn't very flexible, and it broke off the connector when driving around. The sharp end of the whip is also a bit of a safety hazard, which I fixed by sticking one of those foam antenna balls on it. The mass of the ball aggravated the structural problems though.

A bit of modeling shows that the match isn't all that hot (about 29 ohms, with a healthy reactive component), but, the output transistor from the transmitter doesn't get too hot, and the mismatch will only reduce the radiated power by about 0.5 to 1 dB, so we'll leave it this way for a while.


radio/antenna/bucketwhip.htm - 28 Jan 2002 - Jim Lux
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