This year there were three entries in the Blackwood Cup contested at the October meeting ( Wednesday 17 October) at the Lutheran Church Hall, King St, Mt Cook, Wellington.
Bernard ZL2BD showed off a couple of SWR meters. One of these covered both HF (using a standard pair of toroids in a bridge circuit) and VHF/UHF (using a stripline circuit). Bernard separates the sensor components from the metering components so that the bridge can be located somewhere remotely as required.
Mike ZL1AXG showed off his completed “Hiland” 0-30v 0-2A power supply and talked about a couple of the glitches he uncovered. Occasionally when turning the unit on, the supply will not move off zero volts. This is thought to be a function of the slightly different specs for the op amps, which were substituted. The other fault is in the cheap $2.70 Aliexpress digital volt/ammeter. The ammeter reports double the actual current!
Doug ZL2AOV talked to his uBITx transceiver and an extensive range of modifications, including built in battery, VOX and S-meter.
The Blackwood Cup moves on from Mike ZL1AXG’s shack to Doug ZL2AOV’s shack, as he was declared the winner by Malcolm ZL2UDF.
At the August 2019 meeting we set out to find out which team had the competitive edge in finding a set of crystals that would be useful in a 12 MHz crystal filter? Bernard and Frank found 3 crystals within 30Hz of each other. They were part way to getting a set of eight. A bit harder than everybody thought, but many learnt some techniques in sorting out crystal suitability. The other two teams each found 2 pairs of crystals that would meet the required specifications.