The room was electric with excitement (well almost !) after the conclusion of the business portion of Februaryâs Branch 05 monthly meeting.
Several club members had been like Busy Bees over the Christmas New Year period and constructed Home Brew antennas. The idea was something simple (preferably mountable as a vertical) which would work on the 2 metre and 70 cm (VHF/UHF) bands.
Something which a new user might find useful in boosting the ability of a basic Baofeng to reliably access local repeaters. Cost and ease of construction were also considerations, as well as overall good looks and âmarketabilityâ in case the club wanted to later assemble kitsets or antennas for sale.
Rob ZL3RX and Richard ZL4FZ had arranged a testing system, so they could read remotely, how much signal the repeater was receiving at its input.
The first âshow-and-tellâ was Ian ZL3TAOâs âMoxonâ. I thought that sounded like some kind of vitamin pill, but it is a flat antenna, that can be as simple as copper foil or wire laid on a flat cardboard base, possibly even attached to a wall like a painting. Indeed Ianâs construction included extra photographs heâd printed out and stuck on. The design specifications came from the internet and were translated by Google from one, (or more ?) of those Russian region languages. Then the
âMoxonâ antenna was taken outside for testing. It was the cheapest construction at $12.50 .
David ZL3ASNâs Dual Dipole looked smart, made from plastic conduit. Heâd left it unglued so it could be disassembled for SOTA and portable use. However with glued joints and waterproofing it could be used outdoors more permanently Cost was kept low with some connectors sourced from the $2 shop, total cost just $20 . There was discussion that a bulk purchase of plastic conduit might further reduce the cost in future.
Stuart ZL3ART had perhaps the most visually impressive antenna on the night. Of an Open Stub J-pole design, it was already attached to a wooden support over 2 metres long, which made it rather large and unwieldy as tried to hold it erect inside the clubrooms. The construction cost was about $50.
Blair ZL3TOY should have been charged double the free entry fee, as he had two antennas. The first was a âPopavicâ with an unusual angled shape, which cost about $30 including the coax and some ferrites. He reckoned one expense was the strip connectors, the larger 5mm size costing $26 for a 10-strip of them at Ideal Industries (therefore $5.20 for them alone).
Blairâs second offering was an End Fed Half Wave. This was based on a design by Lee Jennings (SK) of the Napier club. It uses fibreglass sections that could be bought as âfactory secondsâ from Killwell a North Island based fishing rod manufacturer. The fibreglass was about half of the $30 total cost. This antenna looked neat, but to me it seemed to be especially problematic as Blair described how difficult it was to tune it correctly.
Last was an unofficial entry from Steve ZL2UIX. His SlimJim antenna was made mostly from 300 ohm ribbon and could be rolled up and hidden in his hat. Intended mostly for SOTA style work. It would have cost less than $15.
Then some printed score sheets were handed out and folks were encouraged to break into groups of twos and threes where we sat. Our third person was a Bruce but he suddenly became invisible, so as âTeam Fâ.
Peter ZL3IA and Catherine ZL3CATH worked through the score sheet, one by one trying to score the antennas all fairly across the various criteria. Later President, Ian ZL3TAO collated every teamsâ results on a spreadsheet. The results were surprisingly close, with Davidâs Dual Dipole outright winner and Stuartâs OSJpole a close second.
My personal favourites were Blairâs Popavic (which somehow scored lowest, although I thought it looked âFunkyâ in a good way !) And also Davidâs Dual Dipole.
Results of the antenna âcontestâ, with the final scored based on the cost, RSS at the repeater and the VSWR Return Loss.
| Entrant | Cost | Cost plus 10% | 147.65 RSS | 434.875 RSS | 147.65 RL | 434.875 RL | Score Total |
| ZL3TAO moxon | $12.50 | $13.75 | -77 | -88 | 22dB | 21dB | 104 |
| ZL3ASN dual dipole | $20 | $22 | -67 | -93 | 9.8dB | 17dB | 116 |
| ZL3ART osip | $50 | $55 | -62 | -88 | 19dB | 20.5dB | 112 |
| ZL3TOY popovic | $30 | $33 | ? | ? | 12.3dB | 17.75dB | 68 |
| ZLTOY efhw | $30 | $33 | -63 | -85 | 12.8dB | 9.8dB | 107 |
| ZL2UXC slimjim | $15 | $16.50 | -81 | -100 | 16dB | 9.5dB | 94 |
| Comparison Baofeng Rubber Duckie | $5 | $5.50 | -88 | -88 | 14.1dB | 15.7dB | ? |
Words and photo’s by Catherine ZL3CATH.
