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VK6RAV - AVON VALLEY REPEATER MAINTENANCE 2014
Assisting in the maintenance of VK6RAV repeater tower and the installation of the antenna..

VK6RAV - Avon Valley Repeater Maintenance 2014  

The installation of the 2 metre band antenna was only part of the overall work carried out at the VK6RAV repeater site in 2014. The largest activity was in fact the replacement of all 36 tower guy wires. Below is an edit collection of progress email report issued after each activity. 

Saturday 15/02/2014

The working bee on Saturday 15/02/2014 has replaced the lowest group of guy wires successfully. The work was a little slow as we were still refining our techniques’ with last guy wire of the group taking less than 20 minutes. See photos of guy terminations.  

Newly installed guy wire 

Saturday 22/02/2014

The working bee on Saturday 22/02/2014 continued replacing the lower guy wires with a significant improvement in productivity. The lowest guy wire group was replace on the previous visit and an additional three guy wire groups being replaced on the on this visit. My rough estimation suggests that this is approximately 25 – 30% of the project completed. All members of the crew were happy with the productivity and safety of the techniques.

Antenna inspection The locals

Saturday 29/03/2014

The working bee on Saturday 29/03/2014 was intended to continue replacing the remaining guy wire; however work was slow as we are encountering logistical challenges now that we are work near the top of the mast. The first issues was the entanglement of the haul rope in a newly attached guy wire that finally forced the ground crew to un-attach the ground end of the guy to untangle the rope. Finally despite an ideal start to the day winds picked to an unacceptable level resulting in aerial activities being cut short.

The day achieved some early essential retentioning work on the guy wires and the tower was checked for straightness and verticalness with the theodolite, which surprisingly showed that the top of the tower was only out by 3” (75mm). The aerial work achieved the installation of three guy wires at the Guy Wire Group 10 level.

Looking serious at 25m above the ground Checked for straightness and verticalness with the theodolite.

Saturday 05/04/2014

The working bee on Saturday 05/04/2014 installed the final guy wire; that is all 36 guy wires have now been replaced with 18 of the original guy wires to be cut away at a future working bee. The decision to stop removing existing guy wires are went was made at the half way level to provide additional tower stability for the higher tower work as there is quite a bit of disturbing movement and twisting in the tower’s upper levels.

The final 6 guy wire installed on the 05/04/2014 working bee were obviously the longest and we had selected a heavier 5mm diameter wire as compared with the 4mm used on all the lower guys, this created a significant handling issue so we determined that it would be more efficient to cut and terminate all the guy wires on the ground and haul them up the tower in quick succession to be attached to the tower. The ground attachments would be made once all guy wires were attached to the tower. As the roll of wire was an unknown length there was a possibility that we did have enough and so it was crucially important that the pre-cut guys didn’t use much additional wire beyond what was actually needed. Norm Fox and I had independently calculated the precise wire lengths of the proposed guy wires and despite a bit of doubt and a lot of pressure from Jim Nicol and Peter Hackett we stuck to our calculations and were proven to centre metre accuracy; well 30cm accuracy.  

Guy wire group Distance from tower base to ground attachment (Mtr) Tower attachment above ground (Mtr) Guy wire length (Mtr Rounded up to 3 decimal place) Guy wire length plus 5m termination tails (Mtr Rounded up to 1 decimal place)
1 20.22 4.790 20.780 25.8
2 20.22 9.280 22.248 27.3
3 20.46 13.770 24.663 29.7
4 20.46 18.260 27.424 32.5
5 20.72 22.750 30.772 35.8
6 20.72 27.240 34.225 39.3
7 30.16 31.730 43.777 48.8
8 30.16 36.220 47.133 52.2
9 30.4 40.710 50.809 55.9
10 30.4 45.200 54.473 59.5
11 30.66 49.690 58.388 63.4
12 30.66 54.180 62.254 67.3

 

 Guy wire cutting and terminating  Guy wire tensioning

Wednesday 23/04/2014

A working bee of opportunity was carried out on Wednesday 23/04/2014 to remove the existing commercial antenna at the top of the mast and install the new 2 metre band collinear antenna. Despite similar rope hauling problems that have plagued previous work at and near the top of the tower I’m am extremely pleased to report the new antenna is now installed and functioning perfectly. Checks around the district including the Perth suburbs have confirmed radiation pattern modelling. Peter Savage (VK6YV) reported a 2 to 3 ‘S’ point improvement in the repeater signal strength at Wanneroo and we have had other signal reports suggesting similar strength improvements’.  

We are all very keen to hear any signal reports from various locations and comments about the repeater’s performance in general, so please send to this email address and enjoy Western Australian’s best coverage 2 metre band repeater.

Video of the removal of the unused commercial antenna array and the installation of the new 2m collinear antenna.

VK6RAV coverage foot print based on typical mobile radio set up.

Saturday 10/05/2014

Working bee carried out on Saturday 10/05/2014 to cut the existing guy old guy wires off a the ground attachments and carry out tensioning of the new guy wires now that they were carrying the full load. Initially all 36 guy wires were checked and adjusted to achieve a 10% of the wire breaking load. The tower was then checked for straightness and various wires were slackened while others had there tension increased until the tower was acceptably straight and all guys were at the desired tension of 10% WBL.

With the lower half of the old guy wires having been removed early in the project the remaining upper guys were to be cut free and removed however as I climbed towards the half way level a rain cell moved across the site resulting in the aerial activities being call off for the day after a hasty and wet retreat from the tower. All good clean fun……

 Top of the mast with the new 2m band antenna.  One of the new guy wire ground anchors.

 

 

 

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Page last revised 20 June, 2014  
 

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