Josh Mesilane – VK2MES is the custodian of the Bathurst Repeaters
Details:
VHF FM Repeater:
Located on the “Old Mill” site in Raglan NSW, just on the eastern side of Bathurst
Frequency: 146.900 / -600KHz (Negative Offset)
No tone is required
VK2RKG is linked to VK2RCW at Gowan via 70cm
UHF DMR Repeater:
Located on the approximate top of the “crest” in West Bathurst
Frequency: 439.875 / -5.0 MHz (Negative Offset), CC: 1
Static TG505 on TS2
Part of the VKDMR Network
Currently operating on a low power duplex hotspot – higher power Motorola repeater will be installed in the coming weeks.
The VHF Repeater Story:
The Story – How I came to be the custodian:
The repeater was originally formed as the project of Arian – VK2BFN and Paul VK2AHB. An unofficial “Kelso Repeater Group” was formed by a bunch of local interested amateurs to get the project off the ground. The repeater was put together and hosted in Kelso, utilising a couple of FM828 radios, some progrocks, a PIC controller and a pair of Phillips FM828 Radios. As time went on and weather got into the antennas the repeater went offline and an overhaul was needed. That’s where I (Josh – VK2MES) came into the picture.
All of the bits and pieces of the repeater were gathered and moved to Josh’s place and it was found to have a UniLab VHF repeater unit that was already programmed for this purpose in the “box of bits”. It is understood that this radio was sourced after the repeater was originally put together and never pressed into service. The repeater previously had cavities donated from SGARS and had been tuned to work with two separate dipole antennas to provide enough separation. After speaking to Dave – VK2JDS it was established that the cavities didn’t have sufficient rejection to run the repeater on a single antenna.
I enlisted Dave’s assistance and he took and modified three of the existing cavities to revere the peak/notch image and also provided two more cavities (for a total four in each string) to achieve the requisite 120db rejection per string. Dave also manufactured the combining link (the length of which is somewhat of a dark art that I don’t quite understand) for use with a single antenna.
While all of this was going on I set about putting together a controller to use with the UniLab unit, based on an Arduino.
Gary – VK2GLJ then donated a spare Diamond VHF antenna and all of the pieces were then combined to get the repeater back online.
The repeater was tested and found to have nearly twice the original coverage area – despite Josh’s place not being the quietest place RF wise, especially on UHF.
Throughout this work the previous licensee offered to transfer the license to Josh – as it now made sense to do so with Josh looking after the repeater.
Then Dave and Josh had a crazy idea.
You see – the whole point of setting up a repeater in Bathurst was to provide a VHF repeater coverage of the Bathurst area – an area that’s shadowed by VK2RCW at Gowan in the Central West.
What if this repeater could be linked to VK2RCW? But – with what gear? Terry VK2MTJ already had an experimental UHF simplex link set up at his place to RCW – so this was a good place to start.
Josh eventually sourced, some UHF Unilab Radios from Paul VK2GX’s personal supply and Josh set about programming the radios for use to connect VK2RKG and VK2RCW via Terrys link. There was a problem though – we needed to run a simplex radio to Terrys link, and the UniLabs were setup as Duplex. The Unilabs do have a simplex relay option – but they’re basically unobtanium. Josh ended up designing a simplex relay board based on a HF356 surface mount relay, and after some PCBs express from China and a bit of a wait they arrived and we had simplex unilabs!
There was some messing messing around with EEPROM erazers, readers, writers, bad chips and a bunch of other issues but we got the UHF radio programmed. Josh sourced a cheap 3 element Yagi antenna (as the end goal would be to link directly to RCW) and put it on the mast out the back with the VHF antenna.
Now we needed to figure out the controller via Terry’s link. This needed some changes to the controller to handle the extra audio and the tail off the link – but not to worry with some clever programming Josh got it all working and we had a connection. It was a bit like superglue and duct-tape but it all worked. Josh took the original birds-nested controller and dumped it into Eagle, and produced a through-hole produced version of the controller board. Again express from China.
Always room for improvement. To move from Terry’s link to RCW direct.
VK2RCW already had a UHF frequency pair that weren’t in use, so we programmed up a second UniLab, and as this won’t be a general access radio we configured it for simplex. This had the added advantage of not needing to mess around with tuning another set of cavities at the RCW site. Dave sourced a Yagi antenna and installed the radio at the RCW site and pointed it as Josh’s place. Josh flipped the frequency of the Unilab and we got it working. There were some minor adjustment of the antennas, but our aiming was more or less within 30 degrees or so. Not bad for an educated guess.
During this process Josh again revised the controller board for further improvements, including all surface mount components – more indicator LEDs – dedicated muting of the input audio lines, a buffer amp for a discriminator input, better filtering of morse and tone encode options – should we ever decide to go down the route of tone encoding in the future as well as a few other bits and pieces.
A new home.
Obviously there was an advantage to the repeater being at Josh’s place during the overhaul but a more permanent solution needed to be found. Josh’s place is in town, and RF wise is quite noisy. Various locations were discussed but Josh eventually gained access to a site in Raglan with no other RF services present on the site.
Some discussion was had an Gary VK2GJL again donated an antenna mast to use at this site.
The repeater has now been moved to it’s new permanent home in Raglan, where it is now operating with better range, efficiency, sensitivity than ever before. The repeater is public and open access to anyone.
Future Plans:
Well, who knows what we’ll do with it in the future. Right now it’s providing services to the Bathurst area with reliance on RCW for wider area coverage.
VK2RDX is on a nice hill that covers the Sydney basin and out west to Bathurst area – Im not saying we couldn’t set up a link 🙂