From L-R VK7’s OO, BEN, ZBX, HRS and HH with their antennas. Photo: VK7MO
While many people enjoyed southern Tasmania’s Hobart Show public holiday, Rex VK7MO played host to a group of amateurs building antennas for 1296Mhz (23cm).
VK7s OO, BEN, ZBX, HRS and HH all attended from early in the morning to build Yagi’s suitable for 23cm. While most were content to built antennas with 18-21 elements, Richard VK7ZBX set himself a challenge in building a 70 (yes 70) element yagi, with a boom length of 6 metres!
The work is not over though, with building to continue on Saturday.
Wednesday the 16th October saw 14 people visited the Lion Drinks & Milk Company at Lenah Valley.
Firstly a huge thank you to Dale Barnes VK7DG who is the chief engineer and David Goodrick VK7FABE who is a Dairy Technologist at the factory.
We all assembled in the lunch room and kitted up with personal protective equipment including glasses, dust coats hair and beard nets and shoe covers. A wash of the hands and we entered one of the cleanest factories you will ever see! The maze of food grade stainless steel pipe work is a wonder to behold!
We started at the loading dock where the B-Double milk trucks back in and unload into the refrigerated holding tanks. We then went into the valve matrix room where the milk is routed from the tanks into the various pasteurises. The valve matrix is fully PLC controlled and Dale explained the Profibus system and how it is used to control valve, motors, etc.
We then headed into the pasteurising area where the milk is heat to 76 degrees for a certain period of time then chilled back down through heat exchangers. This was also the room that contained the Central Processing Unit for all the process control throughout the factory. Many screens showed the processes going on throughout the factory.
It was then into the carton and bottle filling lines. These are highly automated processes where bottles are flying in from conveyor systems into the fillers and capping processes and then moved out into milk crates where they are automatically packed and sent to the cold stores ready to be shipped out. The milk carton folding, filling and sealing machine was fascinating.
It was then up to the pasteurising room where there are 10 tanks and a valve matrix switching arrangement that takes four input and 10 tanks or outputs and can switch any input to any output based on what the PLC is telling it via the touch screen – operator control panels. The array of sensors in use is mind boggling, these all tell the PLC when different parts of the process are starting and finishing, radar units telling depth of liquid, interrupt sensors and many others.
We finished in the power and motors control room with an array of switch gear and PLC control panels for the various motors used within the plant.
We looked at our watches and wondered where that two hours went! We thanked Dale and David and headed home and I am sure we will not look at that litre of milk the same way again!
(73, Justin, VK7TW)