QDX Shed Workshop

Wellgood loop - a broadband RX only loop Our recent shed workshop on 4 October was held at Bernard ZL2BD's QTH at 1 Winsley Tce, Churton Park. RX Only Magnetic Loops The workshop summarised further RX Magnetic Loop experiments undertaken by Bernard ZL2XJ and answered the following questions. Is a broadband RX loop as good as a tuned loop? No. A tuned loop results in around 6dB better signal/noise ratio and will allow you to hear stations that cannot be heard on a broadband RX magnetic loop antenna. However, the broadband loop has its place in that re-tuning is not required (e.g. in a remote SDR receiver situation). It may also be difficult to tune a single loop across a broad spectrum (e.g. 150kHz to 30MHz). Do you still get an advantage in using a phasing device to null out noise? Yes. Phasing two RX antennas will also give you an additional lift in Signal/Noise Ratio. Would a RX only loop be better than a TX loop for most amateur operators? A TX loop if designed and built correctly can approach or equal the performance of typical amateur low band antennas (e.g. for 160m and 80m) that will necessarily be…

SDR Spectrum Analyzer Our Ted Talk for the year (from Ted ZL2TB) was scheduled for Sunday 2 August from 1pm to 3pm at Ted's QTH, 14 Quigley St, Newlands. Thirteen members enjoyed Ted's introduction to his low cost SDR Spectrum Analyser (available for around $500) that can be procured through the internet. This device can be used for all sorts of purposes, with slightly differing models having slightly different features. Ted gave a practical demonstration of potential use cases that reflected his personal interests in the VHF, UHF and microwave spectrum, such as looking at the output of the FM radio stations on Mt Kaukau in Wellington, the transponder outputs (including half transponders) from satellite signals able to be received in Wellington. Given the affordability of the device and potential to examine a broad spectrum all at once, this session was of interest to members.

On 1 March from 12 noon -3pm we met over a light lunch at Mike ZL1AXG's QTH. The Branch 50 NZART Committee ordered in a light finger-food lunch (savouries and sandwiches) as we were hosting Branch 74 for a combined branches event. Disappointingly, only two guests showed up ... they were our guest speaker for the workshop, and one Branch 74 member! Mike noted that the year had not got off to a good start with few turning up for the combined branches BBQ organised by Kapiti Branch. It appears many amateurs simply don't want to come out any more to events. However, complacency may well spell the end of amateur radio as we know it. Member attendances at most branches appear to be plummeting, even those that still have 100+ members on their books. Things are getting tougher for ham radio, with suburban QRM often sending the meter over s9 on the low bands, the sunspot cycle likely to be at its worst for some years, and Councils getting tougher in their district plans on amateur antennas (see the recent decision by Kapiti District Council). It is likely that something radical will be required to breathe new life into…