DATV Experimenter's Night - 23 September 2020 - EFHW, Optical Comms, LED Panels and NanoVNA

We started the night with Ben VK7BEN in the studio describing his End Fed Half Wave kits. Ben took us through his inspiration for experimenting with and EFHW antenna and his liaison with VK3IL and Owen Duffy who helped with the optimisation and development of the kit. Ben took us through a presentation on his measurements of the antenna with the experimentation with the wire and counterpoise. The counterpoise is formed by the feeding coax and Ben experimented with differing lengths. Justin VK7TW then took the audience through his experience with building the kit and how impressed he was with the results. Justin then described the additions he made to the matching Un-Un box which included a counterpoise banana plug and variable capacitor. Ben finished off with the experiences with running the antenna as a sloper and inverted vee. Thanks Ben.

Rex VK7MO then took the audience through his experiments with Richard VK7ZBX using Justin's Tektronixs Photometer to measure and show that the current through an LED is linear to the light output. Rex then showed the experiments using very small (800 microhertz) bin widths in Spectrum Lab to accurately measure a tone at very low light levels over the Non-line of sight path between Rex and Richard's QTHs. Thanks Rex.

Ron Cullen then took us through the conversions he has been doing on monitor LCD screen to build a solar powered skylight. The inspiration for this came from the website - DIY Perks -    • Turning Smashed TVs into Realistic Ar...  . This youtube channel shows the conversion of old TVs and monitors into LED powered light panels. Ron is using this to light a dark passage-way. Ron showed his panels and the various ways to power them from the existing modules or with 12VDC with the replacement LED strips. Thnis is a great bit of repurposing of e-waste. Thanks Ron.

We finished off with a demonstration of how to use the transform function on the NanoVNA to measure the length of a piece of coax.