Author: webdev

On Saturday 19-4-25 Norbert VK5MQ, Tom VK5NFT and John VK5DJ travelled to The Bluff between Millicent and Mt Gambier to continue the development of the VK5RMG site.

The low voltage distribution had been temporarily wired to enable operation of the site. Norbert’s aim was to achieve a system of sub mains and increased wire size to minimise voltage drop now that the site was powered by our 800W solar system.
Tom was able to assist Norbert while John supervised from the chair and maintained discipline 🙂

Power distribution was completed to our two electricians’ satisfaction. The solar inverter, battery and related parts formed the main components of the power supply and branching from this were the two sub mains – one going to the two metre linked system and the other to the UHF C4FM/FM repeater cabinet. All three cabinets and units were fitted with circuit breakers to enable individual cabinet and repeater isolation from the battery.

The solar charge (voltage and current) to the battery, may be monitored remotely through the Internet. Because the equipment supplies are fed directly from the battery our remote system does not show the load voltage and current. This can be approximated by knowing that for a fully charged battery the  charge current approximates the load current. Current indications suggest that maximum voltage drop in the fully transmitting state is <0.2V due to the heavy cable in use.

Norbert installed an N-type connector to the link antenna to Naracoorte while Tom installed a dry powder extinguisher. Thanks Norbert and Tom, jobs well done.

In the near future Peter and Nick will replace the link antenna at Naracoorte and we should then have the Willalooka/Naracoorte branch working again.

In the coming weeks we will install a low voltage detector (not shown). Its purpose it to determine if battery volts have become dangerously low and if so turn on the battery charger (see 4 meters in right hand cabinet). On current evidence this may be required mid winter only. In addition, the temporary link antenna to Naracoorte will be replaced with a more sturdy yagi.

On the weekend of 3/4 May 2025, SERG supported the Generations in Jazz Festival near Mt Gambier. The Festival involves about 4000 students in music competitions and has been held for many years, growing ever stronger. Trumpeter/Musician James Morrison was an important catalyst in promoting and supporting the event, especially in its early days. It started small in 1987 and was supported by the Secondary Schools of the Lower South East. More schools wanted to be involved and it has now grown into a huge event drawing from schools across South Australia and Victoria.

Here’s an extract from the GIJ website

Mount Gambier, in South Australia’s Limestone Coast, is Australia’s hotspot for this high-energy sound – largely thanks to a unique annual event called Generations in Jazz (GIJ).​

Established in 1987, this spectacular gathering on the outskirts of the city, made famous for its Blue Lake, not only attracts the jazz legends of today but also the bright stars of tomorrow.

​Generations in Jazz holds a special place in the jazz culture of Australia, where one generation of brilliant musicians inspires the next, and aspiring musicians get a taste of life as professional musicians. It’s where like-minded individuals gather to learn from each other, study, and perform.

The South East Radio Group (SERG) provides the communications for the event and this is facilitated by the addition of our portable repeater (VK5SR) that enables excellent signals across the very large site. The members of SERG fulfill an important coordination of activities but also a safety umbrella in the event of unforeseen happenings.

All those handhelds are to various places on the grounds, Kate has to manage all that at once. Maxwell VK5AC looking on in awe at the UHF DMR handsets. The SERG operators on 2M had the benefit of strong signals and the headsets.

Headsets were mandatory for those operators in the tents as the noise was huge.

Photos courtesy of Greg VK5ZGY and Tom VK5NFT

Last Friday 28/3/25, Kate  VK5FKLY and Tom VK5NFT did some work at VK5RSE Mount Graham.

They delivered the phasing harness for the new antenna and short lengths of cable to the concrete bunker at Mt Graham and to their surprise were overwhelmed with the lady bugs. A variety that lives in the close by forest pine trees.

Later the same day in the evening Kate and Tom went back to Mt Graham to remove the bugs. Kate vacuumed up a large amount while Tom repaired and filled in where they had been coming in.

Hopefully that has slowed them down from gaining entry into the repeater hut.

Tom also attended to some weeds at the base of the door as they prevented the door from opening. He also stored the loose screws etc that were scattered on the cabinet in a plastic container to prevent them being lost.

Some more work needs doing up there but for the moment its much better.

Thanks Tom and Kate.

The big move to another location on The Bluff was completed on 23/3/25.

A great turn out of helpers attended, all contributing in some way.

The new location is now running entirely on solar power. This will save nearly $1000/year in power costs. We have a wonderful new sponsor in the form of LimeFM, they’ve provided the space on the tower and the use of their battery room for our equipment in exchange for the maintenance of their equipment and solar system. We both benefit, we’re both winners.

A few small matters to tidy up e.g. improved DC distribution in the hands of Norbert VK5MQ and some antenna cable work by Peter VK5BE will be done over the next week or so. At present the 70cm link to Naracoorte is disconnected due to some work to be done on the connector and shortening of the heliax.

It’s a great result and due to some shortening of cables we seem to have also improved the coverage a little – a great bonus.

On Friday 21 Feb Peter VK5BE and Nick VK5NJS installed the UHF/C4FM (439.825MHz out) repeater in the newly approved home for our repeaters at The Bluff. The repeater can be used as either an FM repeater or as a C4FM device depending on your transmit setting. No 91.5Hz tone is required.

We’re off grid and our 4 of 190W solar panels are doing their job through the club’s MMPT controller. The condition of charge, voltages from the PV, the battery and the load and their respective currents are capable of being monitored remotely and those monitoring can see the condition of the systems from the comfort of our arm chairs. Well done to all those involved in the project to date.

The next step, not too far into the future, will involve the transfer of the two remaining UHF link antennas from the old tower and then the 2M gear can be transferred to the new, more spacious building. We can hardly wait.

The photos below were taken by Nick on a trip to The Bluff on Sunday morning 23/2/25.

The door project is complete

A huge “Thank you” to Greg and Owen who did most of the work. A big “thank you” also must go to Andrew VK5VKC, for driving the forklift to the Reidy Park Centre from the yard on Penola Road and back and to Coates Hire for lending the forklift to us free of charge.

A big “Thank you” also to Nick VK5NJS, for welding in the new sections of the door guide and to Jack VK5EBA, Leith VK5FLAR, Maxwell VK5AC and John VK5JOB, for assisting when required.

On Sunday 17th November Maxwell VK5AC and John VK5DJ restored the beacons to their home at Mt Graham.

Maxwell had conducted considerable work on the beacons. This involved preventing some instability on 1296.550 MHz and a failed amplifier module on 432.55MHz. The fans had also seized. The DTMF control was checked.

At the site Maxwell installed an adapter that allowed audio to be extracted from the 146.2MHz receiver and conveyed to the DTMF chip in the beacon box.

Some re-arrangement of the boxes was also made while on site. The repeater and link system is now on top and the beacons below. This permits easier access to all the equipment.

From the top:
Link System on 430.475 with antenna to The Bluff (VK5RMG). Link system on 440.025 with antenna to Mt Benson (VK5RKN)
Repeater 146.2 in/146.8 out. this repeater is running on temporary antennas at present but providing reasonable coverage.
Controller for Beacons on 144.550, 432.550 and 1296.550MHz
Amplifier stages for beacons

Note 1296MHz is currently off due to antenna failure.

THE SERG PORTABLE BROADCAST HUT.

As most of you will never see this I thought that I might give you a glimpse.
A number of members have put a great deal of work into this project, particularly Peter, VK5BE and Nick, VK5NJS.


The cable shelving, (built by Greg, VK5ZGY), at the rear on the left hand wall. The steel cabinets for sundry items. The air conditioner will be removed as it is too big. The hooks for sundry items on the back wall made by Nick, VK5NJS.

The operating desk made by Owen, VK5HOS, and Andrew, VK5MAS. (Note the clever recessing of the console to allow the operators wrist and hand to remain on the desk).

There is still a lot to do but we appear to be well on track for its first outing at the Legend of The Lakes Hillclimb in November.

President Peter

The portable-antennas.com site is a must have when you want to build a wire antenna. It takes into account all the factors that affect the lengths of the wire for many common wire antennas e.g. height of each attachment point, soil type, diameter of wire and its insulation, feed point, distance from end poles and much more. It is all in metric so no need to convert to feet and inches. Very impressive.

Types covered include normal or linked dipoles, off centre fed, end fed, vertical, delta loop, half square, Moxon and a general section.

It’s well worth a look. I’ve put a permanent link to the site in the Links page too as posts gradually disappear into the archives.