Amateur Radio New South Wales held a 40 metre dipole “buildathon” at Dural earlier this month. The event was aimed at helping Foundation licensees get onto HF, though some Amateurs with other licence grades turned up too.
From our club, Sajith VK2FAST and Shaun VK2XPP participated, and Richard VK2SKY came along to “hold hands” and help with any technical difficulties.
The dipole kit consisted of:
- a TET Emtron 1:1 balun kit (4:1 balun kits were on hand too)
- 22m of kevlar-cored copper wire (available from ARNSW for about $1/metre)
- 15m of RG58 coax cable
- two PL-259 plugs
(The balun kit and other components could also be purchased separately.)
The full kit was available to participants at a discounted price; the above configuration was $45, just a few dollars more than the retail price of the balun kit. Membership (currently $10/year), as they say, has its benefits!
Soldering irons, tools, and meters were available as needed.
To save the group some building and troubleshooting time, the baluns were partially assembled, i.e. the toroids already wound.
A test rig comprising a squid pole, ropes and end supports made it easy to get the antennas in the air. A rig and SWR meter were at the ready to check the antennas and adjust the centre frequencies, but VK2SKY brought along his trusty YouKits FG-02 antenna analyser, which made light work of the testing and adjustments. It proved instructive to demonstrate how trimming the ends of the antenna raised the resonant frequency, showing the SWR curve over the entire 40m band.
The very first antenna tested had a bizarre fault, which was traced down to the PL-259 plug. Excessive solder on the centre pin made it hard to insert it into that balun socket, and when force was applied it pushed the centre connector into the body of the plug slightly, causing it to short-circuit. This of course was after the cable had been tested with a multi-meter and judged to be good. Live and learn!
Among those taking part was Dot VK2DB of the Hornsby club, who took the photo of VK2SKY and VK2FAST while we were testing Sajith’s dipole.
Addendum: according to Tim VK2ZTM at ARNSW, one of the participants, who came down from Coffs Harbour for the event, has since worked stations in Moscow and Chile using the dipole. A happy customer, by all accounts!
ARNSW is seeking suggestions for future events.
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