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Today, March 29th, Peter VK5BE and Colin VK5DK completed the recommissioning of the VK5ROH 70cm repeater at The Bluff, together with the Echo-Link gateway from the Clubrooms.
All appears to be working as it should.
Attached pics are of the Echolink antenna and measurements at the Clubrooms.
Cheers,
Peter
PS : I haven’t tested the IRLP facility (Editor: it’s not currently working), so I’m not sure if its working, but Echolink works fine.

From President Peter, VK5BE

Today, Colin VK5DK and I had a very successful activity at The Bluff to restore our 70cm repeater, VK5ROH, following the mounting of the dipole array last week-end on the Hutchesson tower.

Correct galvanised bolts fitted to the array mounting brackets.
Dipole array realigned to face north.
Coaxial cables neatly routed down the tower to our hut.
Custom cut extension cables using RG-213 installed to the rack equipment.

Tx SWR = 1.13 to 1
Rx SWR = 1.08 to 1

Initial signal reports suggest the coverage is as expected.

Note from VK5DJ
At the top of the photo, just to the right of the tip of the Mt Benson yagi you can see a 2M vertical dipole. This was installed by Gambier Electronics for us some months back and had some performance issues when used as a duplexed antenna. Sometime in the next week I plan to drive to The Bluff and put that currently unused antenna on the receiver but leave the transmitter on the top phased dipoles. It’s worth the try to overcome the poor receiver performance. I may be able to remove a received cavity also.

On Sunday 21-3-21 we had a get-together at the Bluff. Tim VK5AV and Norbert VK5MQ set up HF portable operation for the John Moyle field Day. They had some success, Tim using a horizontal wire and Norbert tested his vertical. Forty metres was the best band.

Col VK5DK and Gary VK5JR setup 1296MHz equipment but failures prevented successful operation. An attempt by Gary and Norbert to get a 1296MHz contact over 200m was unsuccessful as the contest time ran out.

It was all great fun, we had a good turn up of members considering the short notice. President Peter also relocated the UHF repeater antennas on the tower although the coaxes will wait another few days.

More work over the weekend. Saturday attendees at the Bluff were Peter VK5BE, Col VK5DK and John VK5DJ.

Three main tasks:
1) Remove the UHF antennas from the fence ready for the site inspection this week.
2) Install the Mt Eckersley/Mt Gambier Clubrooms linking yagi on the Gambier electronics tower.
3) Install an additional filter in the main receiver cavity line.

So what happened?
1) UHF repeater was turned off and the antenna laid on the ground neatly against the fence, Peter guiding the pole and Col and John bravely holding the end of a rope doing the lowering.

2) Peter brought along a long ladder and has installed the yagi pointing at Mt Eckersley about 7 metres above ground level. He and Col arranged the coax in a neat but temporary fashion. Rather than cut the long length of heliax, a temporary coax line was built out of three shorter pieces with two joiners. A compromise until we know if the yagi is high enough to get through to Mt Eckersley. Once this is confirmed we’ll make the coax one length. Tests show that the link is very strong into Mt Gambier and can be heard off the back of the beam in Millicent.

3) It was suspected that there were strong signals (or noise) overloading the 2M receiver. The cavity shown to people last Friday was retuned at Millicent to 146.3MHz and installed on site. Using a return loss device it was possible to show there was an additional 10dB of sensitivity gained by inserting the additional cavity.
As an aside some of the noise from nearby transmitters can still be heard on signals into The Bluff receiver but this can’t be filtered out for obvious reasons. The overload problem is fixed. Noise is just a feature of the site – there is so much RF on the hill.

Some measurements of the cavity performance at spot frequencies:
Commercial TX on site 70MHz -45dB
Commercial FM radio on site 96.1MHz -41dB
Repeater input 146.3MHz -0.39dB
Pagers 148MHz -18dB
Commercial services 160MHz -41dB

What does 45dB down look like? It might be easier to picture that as the power is down by 31,600 times. That is a great filter!
Even 18dB down is a reduction in power of 63 times.

On Sunday Peter and Col returned to the site as the link output had suddenly dropped off and signals became noisy into the link input of the Mount Repeater. Examination showed that the relay had failed in the link. These relays are 40 years old being ex-FM828. Fortunately there was an unused relay system in the link frame so Peter with judicious use of a soldering iron, various tools and great patience, was able to do a successful swap. Well done Peter. The link is now outputting 8W and all is good back to the Mount.

We hope to have the UHF antenna back up later in the week after the site inspection although a more permanent installation onto the tower is planned.

VK3RSW on test – now linked into the SE 2m network

Today, Saturday February 27^th, the Heywood repeater that was put on test recently at our Clubrooms, has now been linked into the South East 2m repeater network.

This repeater will allow members to access the SE network from the city of Mount Gambier, and its immediate surrounds.

This will be of a benefit to those Mount Gambier members who are currently experiencing difficulties in accessing The Bluff repeater due to an ongoing issue with its coverage.

The SERG repeater team have been working tirelessly to provide the best coverage possible during these uncertain times.

The repeater at the Clubrooms transmits on 146.875 MHz, and receives on 146.275 MHz. (No CTCSS tone is required)

It will be available for all Sunday broadcasts, and Friday night meetings and skeds whilst on test.

In order for this linking to occur, the IRLP/Echolink facility on our 70cm repeater will be unavailable until further notice. The 70cm repeater remains available, it’s just that we’ve temporarily made use of the UHF antenna at the clubrooms preventing this end of the link for IRLP/Echolink. Another antenna is being explored.

Peter VK5BE

For the SERG repeater team.

Just a brief update following activities at The Bluff today. Colin VK5DK, Owen VK5HOS and myself (VK5BE) attended.
Owen VK5HOS has a brilliant plan on how to repair the big hole in the floor of the hut. He will manage this issue through to its completion, hopefully by the end of next week.
The pole mounted temporary VHF array has been removed from the site and returned to my QTH until required for the Heywood project.
In its place, a RFI YB9 yagi (450-470MHz) has been installed on the vacated pole, horizontally polarised, and facing the Clubrooms in preparation for linking the Heywood repeater to The Bluff. The yagi SWR was measured at 1.13 to 1 at 449.875MHz.  We figured this was acceptable.
Initial tests show excellent solid signals are being received in Mount Gambier.
Tomorrow we plan plan to erect another yagi at the Clubrooms to link the 2 sites.

Today, Sunday February 21^st, the VK3RSW repeater was placed on test at the SERG Clubrooms in Mount Gambier.

Currently as a stand alone device, and not linked to the 2m network, it is being tested into a single antenna at the top of the Club tower via its cavity filters.

Any member who can trigger this repeater is welcome to use it to test its performance and reliability.

The repeater transmits on 146.875MHz, and receives on 146.275MHz. The CTCSS tone is not enabled.

If the tests prove successful, it may then be linked to our existing 2m network to further evaluate its performance. In the short term, give it a workout. Reports from mobiles and an idea of its range would be appreciated.

Peter VK5BE

Summary of work completed at Bluff today as reported by Norbert VK5MQ:

• Tested LDF4-50 feeder to new dipole antenna. Results were 20.8W into feeder at hut, 17.4W out at top of tower (into RF termination). Same result when connected to new dipole. So re-purposed feeder is OK. !?!
  
• Tested VSWR at top of feeder into new dipole antenna, 1:1.5  . Had a long think and suspected 70MHz dipoles that were at roughly the same level and about a wavelength away. Ideally all dipole arrays/antennas should be vertically spaced to achieve adequate isolation and minimize interaction. OK, then swung the new dipole away from the 70MHz array, about 30 degrees to the west and VSWR came down to 1:1.25  . So that proved to me there was some reflection/interaction with the 70MHz dipoles. Now the new dipole points directly at the Mt Burr summit, so they still are basically oriented to the north.
  
• Found that the phasing harness had one connector incorrectly assembled, with the N type centre pin protruding about 3-5mm proud of the connector. Repaired and tested harness at ground level with two RF terminations and again into one termination and one VHF dipole, VSWR 1:1.3
• Installed second VHF dipole (resolved assembly issue) and phasing harness, VSWR at hut 1:1.03  !! Happy with that.
• Replaced Naracoorte link feeder with known, good LDF4-50 heliax and routed onto cable clips and cable trays into hut. VSWR 1:1.5  and this is what I expected after appraising the condition of the link yagi. I think it’s near the end of life and should been replaced whenever it next totally fails.
• Replaced Mt Benson link feeder with known, good LDF4-50 heliax and routed onto cable clips and cable trays to hut. This work was requested by GE to tidy up coax cables on the tower. VSWR 1:1.03
• Tom VK5EE alerted up the reptile hazards on site at this time of year.
• Signal tests/S meter readings at VK5MQ QTH shows that there is more signal radiated than before these changes.
  

Huge thanks to Tom 5EE and Dylan from GE for massive effort today.

Volunteer needed to fix the hole in the corner of the shack at The Bluff. Will be an entry point for nasties. Minor wood working skills required. Have we got a volunteer?