Mt Wombat Repeater Status Updates

[VK3YNV]

I'm starting this thread to keep people updated as to the status of the Mt Wombat repeaters.

Last night around 5pm the mains power went out and since the battery backup system had failed 2 weeks ago, it means all the repeaters on site are down.

SCA has been in touch and reported that their links are down as well, so it's mains power to the site generally. Further follow up indicates that Strathbogie Shire site is still powered and SCA reports that sites further down the hill are still powered.

I also checked with DELWP and the radios for the fire tower are taken out at the end of the fire season, so we can't easily check mains status by pinging the fire tower. Our mains comes from the same feed point as the fire tower, so that would have been a good place to check.


So it looks like an emergency trip up the hill is required.

Any changes I'll post in this thread.

 

[VK3ZYZ]

I was wondering. At first I thought my hand held in the house had died.

 

[VK3YNV]

Pending any changes between now and tomorrow night, I'd suggest the 8:00pm 2M net be moved to Mt Major VK3RDU.

 

[VK3YNV]

Mt Wombat repeaters are back on air, the problem was the circuit breaker at the fire hut had tripped.

While testing the 6M repeater, it was noticed that touching the power lead to the receiver was causing the receiver to turn off and on.
The problem is the 6M Receiver power connector has overheated and become intermittent so it's being replaced with Anderson power pole connectors.

Also, it looks like the UHF CB repeater Receive antenna connection is intermittent. Still investigating.

Preliminary work to allow the new power management system to be installed has been carried out and the new system can be installed this coming weekend.

 

[VK3YNV]

The mains power went off again yesterday and it's likely the circuit breaker tripped again, we were planning to do the antenna sweeps today anyway, and commission the new power management system, so we will be on air sometime later today for signal reports.

The 6M repeater receiver power connectors have been upgraded, and the Rx sensitivity checked. Also the UHF CB repeater checked out. So its looking like we might have a desense problem with the UHF CB.

 

[VK3YNV]

Update on Mt Wombat work carried out Saturday 31/10/2020

The new power management system is now installed and operational, great work by Josh, so we have battery backup operational on the 2M repeater.
New DC power cabling to all the repeaters with 50A Anderson connectors has been installed.

The control system provides remote current monitoring for each repeater, as well as optional remote control.

Insulation testing on the mains power cabling from the switchboard at the fire hut through to the radio hut didn't show any leakage problems. So it might be a faulty circuit breaker, its a combination type earth leakage overcurrent trip. If the fault persists we will need to replace the circuit breaker, and if that happens we will install surge supression at the same time.

The UHF CB repeater cavities have gone out of tune, and the system is desensing. So, it's reinstalled but currently powered down.

Tests were carried out on the 6M antenna system, the coverage is down compared to the 2M system, Rod Vk3UG reported signal strengths for the SMD on the roof of the hut, compared with the 2 SMD's on the tower, and the single SMD on the hut was better.

Geoff VK3ZNA, did sweeps on all the antennas and recorded the results. We then did a series of tests swapping antenna's around and comparing signal reports. The 2M transmit antenna does a better job than the 6dB colinear, so it will be interesting to compare again after the new antenna is installed.

 

[VK3YNV]

Looks like we lost power again late last night. Still investigating.

 

[VK3YNV]

According to the fire towerman the mains circuit breakers are ok, so we are heading up this morning to see what the problem is.

Meantime, Rod has dropped around the UHFCB cavities and we retuned them last night, so the UHF CB can go back into service.

We were also going to install the KL-70 6M repeater backup. But there are a couple of issues with the transmitter that showed up in testing. So we will remain on the 814 for the time being.

 

[VK3YNV]

The problem was the reverse polarity protection diodes in the power management system blew. We had to bring the unit back to Shepparton to replace diodes with higher current versions. Heading back up to re-install the system shortly. Meantime we have put the 2M and 70cm IRLP system back on line with a patch cable.

 

[VK3YNV]

Power management installed, and all services back on line. I'll post some pictures of the new power management system later tonight.

 

[VK3ZYZ]

Well done Ray and Josh.
They should double your pay

 

[VK3YNV]

Some random snaps from today's trips ( 2x ) to Mt Wombat

The retuned UHF CB cavities travelled in a Rhode&Schwartz road case... ( Ex RA of course )

Overview of the rack, newly installed DC circuit breakers at the top. Power management system under that.

From the top, DSTAR, UHF CB, 70cm IRLP KL450, Tait T800 2M, Motorola 814 6M, and just visible Motorola 30A DC supply
Tait 800 UHF 7Mhz split and DR 3000 DMR are on the left hand side rack.

Lightning arrestor terminations, and UHF CB Cavities.

Back of power management system showing Anderson 50A connections. All repeaters are now
primarily powered by Anderson 50A connectors, much neater and more maintainable.

Each system has a manual override on/off as well as a priority assignment which determines what services are kept up after a mains power fail.
In addition the current and voltage of each is logged into a mysql database and can be displayed in Grafana.

 

[VK3ZYZ]

Josh's control box looks very good.
I think quite a few other sites would benefit from one.

 

[VK3YNV]

Josh has done a very neat job, I think he's planning a write up for the newsletter, what will be interesting is when we get the packet radio interface up and running so you can get data direct from the controller. I wonder how many people still have packet radio gear gathering dust.

 

[VK3YNV]

Geoff VK3FTRK was up on the hill yesterday, sorry I missed him, Josh and I were back in Shepp replacing protection diodes. He took some great pictures. Here's one he took of our tower, you can see the 2M co-linear up the top, and the 6M folded diploes on the left hand side. The 70cm folded diploles on the right. The dual 2M dipoles on the left. The dishes are SCA program links.

 

[VK3ZYZ]

This looks like it may be promising..

ESP32 TNC and Audio Relay for HF/VHF Packet Radio

This ESP32-based device provides Wifi, Bluetooth, and USB serial connections between a host computer and an HF, VHF, or UHF transceiver to facilitate digital data transmission. The device offers two operating modes and an html user interface for mode selection, configuration, and signal...

hackaday.io

I may investigate further.

 

[VK3BLD]

Josh has done a very neat job, I think he's planning a write up for the newsletter, what will be interesting is when we get the packet radio interface up and running so you can get data direct from the controller. I wonder how many people still have packet radio gear gathering dust.

I still have my TNC but haven't heard anything in a long time

 

[VK3ZYZ]

Some pictures this AM, 20201216.

 

[VK3YNV]

Many thanks to Paul VK3YLS and his great crew for a very smooth and professional install of the new 2M receive antenna, This is a picture of the new antenna on it's way up to the top of the tower.

The old 2M receive antenna was in pretty sad state when we got it down and did some forensic analysis.
The top was completely shredded and there was water damage on the coax tail. But the water didn't get past the Type N female to female adaptor
so there was no sign of water in the LDF4-50 coax.

Other work that was done was to cut out a section of water damaged coax on the UHF CB repeater and move the antenna from the hut up to the tower.

The 6M repeater was checked for orientation and length of the tails, and a slight misalignment corrected, and finally swung around about 45 degrees to the south west, to provide a better signal to the south and west.

 

[VK3ZNA]

Many thanks to Paul VK3YLS and his great crew for a very smooth and professional install of the new 2M receive antenna, This is a picture of the new antenna on it's way up to the top of the tower.

View attachment 537

The old 2M receive antenna was in pretty sad state when we got it down and did some forensic analysis.
The top was completely shredded and there was water damage on the coax tail. But the water didn't get past the Type N female to female adaptor
so there was no sign of water in the LDF4-50 coax.

View attachment 538View attachment 539

Other work that was done was to cut out a section of water damaged coax on the UHF CB repeater and move the antenna from the hut up to the tower.

The 6M repeater was checked for orientation and length of the tails, and a slight misalignment corrected, and finally swung around about 45 degrees to the south west, to provide a better signal to the south and west.

An excellent execution of the works at Mt Wombat by Paul VK3YLS and his experienced crew. Well Done!
Having viewed the photograph of the 2m antenna. I would suggest it has been struck by lightning. The blackened interior of the radome tends to reinforce this statement. The shredding is caused by the gas explosion due to the effect of the strike and the top cap would have been blown off and/or shattered by the expanding gas and strike. The tower, not being the highest structure on the hill, would have received a minor strike, our tower is well earthed along with the coax terminations at the hut and the surge arresters in the hut. Whilst the initial strike would be the top of the antenna, the ionized air would insulate further strikes causing the lightning to re-strike further down the tower.
For those not familiar with lightning protection, I would recommend a book written by Roger R Block:- The 'Grounds' for Lightning and EMP Protection. He established the PolyPhaser Corporation in Nevada USA.