HF DX via Balloon Supported Antenna

This page has two HF operations involving a balloon supported antenna. The first operation, the more successful, was performed at Five Dock, an inner-harbour location in Sydney; the second operation occured at Dobroyd Head.

The antenna consisted of about 20 meters of wire for the vertical element attached to a coax centre. A length of wire was attached to the braid to form the counter-poise. This end was to tossed into the salty harbour with some chicken wire mesh.

The balloon was constructed from a 250 litre plastic garbage bag filled with helium (obtained from a party hire store). It was inflated and taped tightly and securely to the vertical wire element. We carefully let the balloon go and as can be seen from the photos, a good result was obtained. Since we were trying to work 80 meter DX into Europe, we tuned up (there's a short window from Australia into Europe at around sunrise). The VSWR was low and before long we were hearing a lot of good signals from Europe through Russia. Also solid (even concrete) was VK5PO, who is a regular 80 meter DXer. Since we were running portable, we were limited to 100 watts with FT-847. A lot of fun was had.

Our second operation was a combination of HF and VHF/UHF DX. Brett is mainly interested in UHF DX. Andrew and I tend to HF. Andrew erected a vertical dipole for 20 meters and we soon had that in the air. We had borrowed an MFJ antenna analyser for this trip (I love this box) and had the system tuned so well I'm sure I could hear the "Hallelujah Chorus". However, a bit of breeze came up and we quickly learned the hard way about the need to guy the system. With a sudden gust, the balloon and dipole broke away from the feedline and very quickly headed for the stratosphere! We considered notifying AMSAT to see if we could get an Oscar designation for our new "satellite" but after a bit of thought, we realised that they're busy with their own problems (AO-40).

Our next excursion we will be trying a new guying system consisting of gelspun fishing line, swivells, a balloon collar, and some weights. This should make the system far more robust.

How much fun can you have?

Shane Magrath
VK2KEP

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