History of VK5RMG

The earliest VK5RMG built by David VK5ZOO was located in Mount Gambier at Channel 8 TV studios, it was never very successful due to desense issues. A new repeater was built by John VK5DJ with chassis work by Trevor VK5NC. Cavities were modified and tuned by Kevin VK5OA and these are still in use today. The repeater made its home at Hutchesson’s Site at The Bluff on 7th August 1982.

Here are some photos of this equipment. Unfortunately the quality of the photos vary, but you’ll get the idea.

VK5RMG circa 1983 ready for install
Inside the boxes is an FM828 TX exciter at left and FM828 receiver at right. The power amplifier sits atop the TX driver box.
Note feedthrough capacitors to minimise desense. The shielding was so effective that no signal could be heard without a wire or antenna plugged into the RX socket. Centre left is a power pot for setting the low power level accessed by remote control. This was designed to save battery power if required. Both the TX and RX are in boxes within boxes to minimise desense.
Remote control by DTMF tones was possible for a smallish number of functions (timer control, repeater off/on, low power/high power and possibly others I have forgotten.
Underneath view of the first repeater. Note the complexity which is now achieved with a single board using a microprocessor. Separate boards for callsign generation, logic control, DTMF decode etc
Repeater installed in the same cabinet used for many years with various upgrades.
(This is the best photo I have, does anyone have a better one?)
Hutchesson’s Electronics wind generator. We plugged into their batteries thanks to owner Trevor VK5TH. 230VAC power was not available on site for many years until other organisations such as Forestry moved onto the site. Trevor’s company was the only organisation on the The Bluff for many years.
The Hutchesson’s tower at VK5RMG during installation of the repeater. Our antenna can be seen about 3/4 of the way up. It is a phased vertical in a fibre glassed radome. This style of antenna was very unreliable through developing bad joints as a result of flexing in the strong winds. Crackles were audible on received signals and finally desense struck. The antenna was replaced at least once but finally changed to a phased, commercial folded dipole arrangement which proved much more reliable.