Best wishes for the New Year - I had a good start to 2012 AR-wise, was able to make a trip south and spent around half a day doing some work on the Busselton site, assisted greatly by Phil VK6SO, who looks after the repeater locally. FYI, brief report below.
Phil VK6SO clearing the scrub around the hut
The main aim of the visit was to replace and upgrade the DC distribution system, clear some of the scrub to reduce the fire risk, and then if time allowed, give the site a full check, continue with other works. In the end we ran out of daylight, but got the essentials of the DC upgrade done, and heaps of clearing (thanks to Phil's hard work on the end of mattock, axe and rake). Attached pics show DC and clearing, before and after. (I have more pics which can be uploaded as relevant).
The area around the hut and mast base has been well cleared, minimising the fire risk. However, further work needs to be arranged, including more clearing around guy points & along guy lines, and dealing with some small trees which are too close to the guy wires for comfort. Not an immediate issue - and we need to check with the landowner before doing any significant clearing - but on the list for future action.
Scrub cleared....VK6RBN hut on left.
I am pleased I was able to progress the DC upgrade, as I have wanted to do this for the last couple of years, but was hard to find time in the rush of everything else.
To explain the upgrade - first, a little about the VK6RBN DC system (as I understand it): the original DC setup was somewhat unique, due to the way this site was first set up in the early 1980s - over the years it was modified/added to piecemeal as extra equipment was added to the site - as this setup aged it became less reliable, and not able to cope with further changes or future upgrades.
VK6RBN has no mains power to the site, and was installed at a time when solar gear was not readily available to WARG. A unique system was installed where several km of low-voltage DC cable was strung through scrub and along fences & trees, back to a location where mains was available. A power system at this location fed around 40V DC or so into the cable - despite the extensive voltage drop, enough DC made it to the site to be regulated and charge a battery, powering the repeater.
This setup worked for some years - however, it needed a lot of maintenance, mainly due to the DC feed cable being repeatedly broken - in the wind, by falling tree limbs, livestock, etc. As soon as solar equipment became available to WARG, the site was upgraded to solar (later 1980s, I think - Will VK6UU's web page has a more comprehensive history). A solar regulator was added to the DC panel, alongside the original DC regulator which was left in place.
Also around this time, a WIA News link RX was added to the site, followed shortly after by a packet digipeater. With the site being solar, more attention had to be paid to battery charge management - the DC system was modified to add a low voltage cut out and a timer. The low voltage cut out disconnected power to the digipeater if the batteries became low. The timer (a household 240V type, modified by Will to work off 12V) was set to power the news RX only during broadcast times, saving the current it would otherwise have drawn sitting idle the rest of the week. The voice repeater was left powered all the time, not controlled by LV or timer.
The original DC panel hadn't been designed for any of these systems, consequently they were just fitted in wherever they would go. Also, after 25-plus years the wiring was aging, terminals were corroding and the backboard was disintegrating. An upgrade was needed that allowed for the site-specific features to continue, in a way that was easier to change for future needs.
Old power distribution panel at VK6RBN
As you can see from the pics, I replaced the backboard with a slightly larger one, fabricated with inbuilt cable tray and making use of industry-standard terminal strips and bus bars for the connections. There is a common -ve busbar (bottom left), and three +ve terminal strips, for (bottom) direct battery connection, (middle) LV cutout, and (top) timer-controlled. Fuse protection is provided for these circuits. The original solar regulator, charge ammeter, timer and LV cutout module were retained and can be seen mounted to the board. There is sufficient room in future to replace/upgrade the LV module or timer, change from fuses to circuit breakers, alter what is controlled by timer or LV, etc. (The existing LV module is probably not rated to control too much equipment.
New power distribution panel.
Parts of the system still need a tidy up as I ran out of time, but you get the idea. The DC feed to the batteries needs upgrading - I re-used the original 6mm, but it's a bit short - I have some 8 or 10mm cable which would be better, job for next time. Also, the existing batteries are at end-of-life - Phil VK6SO has a couple of sources he is chasing up, hopefully some replacements are available at the right price...
If extra gear were contemplated for the site, we would have to look at increasing the overall size of panel array/batteries to cope with the load - in the case of the panels, this might mean significant re-engineering of the solar frame, which is mounted separately to our hut - discussion for a future time.
Also, there is plenty of other work - minor corrosion repairs to guy points, antenna attention is still needed; in the hut there are signs of water ingress (or internal condensation?) and the existing shelving is crumbling (perhaps a racking system to fit the gear, instead of open shelves?) The News link RX is at end-of-life and needs upgrading - has to be a good, sensitive RX which can handle adjacent transmitters and draws minimal current (Hamtronics maybe?)
All of these works need some forethought, design and planning before any action. For now, the site is still well established (mast & hut still in overall good condition), on the air (despite some hiccups) and able to be improved, one step at a time.
All in all it was a good day out, weather was good, not too warm, made some progress. Thanks again to Phil for his efforts.
BR & 73,