This issue (2) continues on with the current progress of the Crafers VK5RAD tower to last
Saturday 26th March. The last 2 working bees were spent scraping and cleaning the loose rust, paint flakes and other dross off the tower structure. The first weekend was on the 19th & 20th (Saturday and Sunday) got going by starting with a BBQ and coffee to prime the enthusiasm of all those who turned up, a big thank you top Roy who set it up, cooked and brewed ready for us all.
A good start to the task at hand !
The team was then let loose with what ever they had, power tools, wire brushes, sandpaper and anything else that could be used to clean the tower structure. We set up a power distribution system that had an earth leakage protector and a plastic box with a tested power distribution board in it, necessary as it had been threatening to rain, and we did not want to risk any body’s safety should it occur, plus the condition of a lot of the power tools brought along was unknown.
Power distribution and many extension cords.
We did this for two days, after which there was a few minor bits that were not completed that would be finished on the following Friday and weekend. Friday saw a few of us complete the process, so the next day - Saturday (26th) was designated as the day to do the rust conversion and perhaps begin painting if we could. Come the morning Roy again set up his coffee pot and biscuit station as we began to arrive, thanks again Roy, a great help to us all.
The work started by spraying the tower sections with a rust converter, an acid based liquid that turns the rusty surface into an iron phosphate and leaves a suitable surface to which the paint will stick well to. It was applied by using a garden sprayer as shown above and this proved to be very successful method and took very little time to complete.
This was allowed to dry, it was fortunate that the day was reasonably warm and a breeze was rapidly drying the acid wash. Before we could begin painting, the structure needed to be pressure washed to remove any excess acid that had not dried and the structure was allowed to dry again before painting began.
The ‘paint’ is a two part process that requires the accurate mixing of the paint and the hardener in specially designed plastic pots that are calibrated with a lot of different ratio markings so that you can get the mix right, the mix we required was a 3:1 – i.e.: 3 parts paint to 1 part hardener. The paint was in a 10 litre plastic can and was worth an arm and a leg i.e. $500 for 10 litres, and the hardener was in 1 Litre tins. The photo below shows what took place. I can only describe the ‘paint’ as slow moving chewing gum, is very heavy, sticky beyond belief and sets fairly quickly.
It is an industrial paint that is designed for use on towers, bridges and anything designed to be in the open and has a quoted working life of at least 30+ years !
The mixing of this was a job in it’s own right, it needed to be carefully poured from the 10 litre container into the mixing bowl, then the correct amount of hardener added then stirred thoroughly before again being decanted into lots of tub, bowls, paint trays etc that the painters were using.
This was done only in 1 litre batches as required, one of the big surprises is how far a small amount would go and the quality of the coverage obtained. Because of its heavy consistency it was hard work even with a roller, but those using paint brushes found it even more difficult to handle and have probably had to resort to a chiropractor this week to get their wrists fixed !
Oh the pain ! Note the calibrated mixing bowl.
The team was then set to work on painting the tower sections and the progress was quite rapid, the photo below shows how we attacked the job, there was paint on the tower, the ground and the operators as well, I now have a pair of trousers that got paint on them and they can stand in the corner by themselves.
Of course, while this was going on, the AHARS cheer squad and support team were there to ably urge us on with the task, please note that they were probably playing pocket marbles !
The Cheer squad.
Work progressed far better than we had anticipated, we originally estimated that we might be able to get two sections of the tower painted, but fairly quickly it turned into 3 sections and by about 3:30 the fourth and final section was starting to be painted as per below.
It wasn’t long before all sections were completed and we could stand back and see how the finished article was going to look. We originally thought that the grey of the paint might make the tower blend into the surrounds too much, a potential hazard for light aircraft and the like, but as can be seen, it is almost white and should present no hazard at all – much better than the rusty colour it was before.
All the sections ready for assembly.
So-What Now ?
The mounting brackets that hold the tower were very corroded and the holes were worn oval because of the different sizes of the holes and bolts that allowed the tower to move in them in storms. These have been repaired, re drilled and hot dip galvanised ready to once again hold the tower in place in a very testing environment, the wind velocities at the site are quite formidable in a storm, plus the rain and electrical discharges don’t help at all either.
A cable ladder has to be mounted to allow the large amount of cables to be fixed, plus the
terminating box for them fitted as well, so there is still a considerable amount of work still to go.
The tower needs to be re-assembled and turned over, there will be sections that will need
to be touched up that we have missed, the pad sections of the feet need to have a small section of weld between the two to make good conductivity between the four sections and make for a very electrically quiet tower that won’t generate noise and intermods.
The earthing of the tower legs needs to be completed when it is erected into place and stable again, the main antennae need to be fitted and the lightening arrestor will be installed on the top of the multi-band array.
Then comes the biggie - Getting it back up in one piece!
A piece of History
I have had a couple of photos sent to me by Colin Rieger VK5ACE that were taken when the tower crashed and damaged it. I am unsure of the date, it is suggested that it was in the 90’s, buit they graphically show what the tower used to look like before and after the event, plus a couple of chaps that you may recognise (or not).
Do you recognise those below ?
from the left is Dave Mincham, Adrian Snell, and Mark Spooner
Obviously taken in the days when we all had hair !!!
My thanks must go to all of those people that have rallied to the call and made themselves available to help out in this project, there is still some distance to go, but at least we can see the light at the end of the tunnel now, I just hope it’s not a train coming the other way !
de Barry, VK5BW
More work was carried out on the tower today (Saturday 19th May 2018). Here are some photos from the day's work.
If you are not getting club emails it means we do not have your email address. A BIG thank you to Barry VK5BW who has been sorting out the AHARS data base that has got into quite a mess over the years. Please email Barry email@example.com with your email address if you are not getting the AHARS group emails. Rest assured you email address will be kept confidential as all group emails are sent out as Blind Carbon Copies that do not display the recipients email addresses.
I have cancelled the technical session for the 26th of May. If the weather is fine there will probably be a work bee at the Craters tower. Barry (VK5BW) and Roy (VK5NRG) open the shack on Saturday mornings are involved in this project, there will be no one to open the shack.
BIG AHARS BUY AND SELL
Thursday May 17, starting at 7:30 pm.
Blackwood Community Centre.
4 Young Street, Blackwood.
(At south end of Coles Supermarket car park).
Auctions and general sales
As most members are aware, the Club repeater at Crafers (VK5RAD) has been suffering noise problems on weak signals, this is caused by loose bolts and corrosion of the tower plus the damage caused by the dozens of lightning strikes the tower receives every year.
The last major strike was in November 2014, which decimated the antenna and it’s radom
covering, and even managed to weld the antenna base to the support pipe at the top of the tower.
This was duly replaced with a new Co-linear antenna, along with a new cable tail and this
successfully returned the system back to normal.
However – as time passed noise began appearing on weaker signals being received due to electrical disturbances in the tower structure with the vibration caused by high winds and other deteriorating hardware on the tower. We had several attempts to fix the situation but we neverwere able to get a permanent fix, and as we want to extend the functions of the repeater with a remote HF outpost at Mt Beevor, this would mean that extra link antennas would be required.
The tower was inspected by a fully licensed rigger, who got to the second level before he
condemned the tower as unsafe and expressed the view that it was a miracle that the tower was still standing. He took photos of items that seemed beyond redemption, such as section bolts that had rusted with no threads and nuts that had disintegrated and almost non existent, as per the examples below.
This meant that for us to use and keep using the tower, that it had to be repaired, this tower also has a commercial service on it, Mt Lofty Coaches, the proprietor of which is also a licensed amateur Dean VK5HMV. This site also has another three amateur repeaters on it, they being VK5RAD 70cm analogue, VK5RAD 70cm C4FM fusion, and VK5RDF 70cm dual mode unit.
It was decided to try and get the tower to a state where it could be lowered to the ground
without any damage to property, personnel and the antennas on the tower. This would allow us towork on the structure at ground level and repair and restore it to a fully fit structure that will give service for at least another 25 years into the future.
The owner of the property was not really interested in refurbishing the tower himself, as he is of advanced years and does not really care it had to be removed for safety reasons. The tower location is really exceptional and gives us good primary service area for a radius of some 160km ranging out in some areas to 260Km depending on propagation on the day.
This meant that the various users had tocome up with the money to fund this project and then approach the land owner for his permission to do this, this was subsequently done and permission was received. Iapproached the Committee and spoke at Club meetings about what needed to be done and approval was given to go ahead with this, the other interested parties have alsoagreed to share costs so the project is avaiable one.
To lower the tower meant that it wouldneed to be made as safe as we could make it and a crane organised to pick it up off itsmountings and lay it over on blocks on the ground. Several crane firms were contacted, but the clear contender was Nick’s cranes asthey had a suitable mobile unit and personnel to do the work. To ensure that the tower was going to bestable for the removal, required some very careful work by riggers to replace critical bolts in the tower structure. This work was done by carefully working up from the ground and replacing those nuts and bolts essential to the structure of the tower, a potentially hazardous job, but one that was done well.
The next move was to provide a continuation of services, this meant that a temporary mast was erected to carry the commercial repeater and a temporary relocation of the VK5RAD repeater to another site at Summertown, this work when completed allowed us to remove all the cables from the equipment and roll them up to be fixed to the tower for retrieval during the repair process.
The crane was booked for the morning on Tuesday 1st of May, and the massive beast (100 tonne) turned up on time, although it took some fancy manoeuvring to get it into the position required, this duly done they prepared to hook up the tower.
To do this the dogman had to be lifted up in the cage basket to the top of the tower to fix the lifting chains, this can be seen on the rear of the crane. The photo below shows the dogman in his cage almost at the height required to fix the chains to the tower. As can be seen the reach of the crane had to be extensive, the tower is some 40 metres high and offset from the crane location by at least 10 -12 metres and the top of the crane boom is above the top of the tower.
The tower was duly secured by the chains and ready to be lifted off, so Dean and myself got busy and removed the securing bolts on the three legs, these had not been removed since the early 70’s, so you can imagine that a lot of brute force and ignorance delivered by sledge hammers and punches was required to move them out of the mounting brackets in the concrete blocks at the base of the tower. Fortunately we had been putting lots of Penetrine and had loosened the nuts on previous days, so this made the work somewhat easier.
There was some discussion as to what the tower weighed, we guessed that it was between 2 to 2.5 tonnes, the crane driver said that it was 2.2 tonnes on the boom, so we were pretty close. With a bit more pressure on and some skilful massaging with the sledge hammer, the tower was at last swinging in the breeze and still in one piece ! The crane was able to swing the tower further to the West which gave us a lot more room to fit the apex on to work area.
The tower on the way down, this was probably the most tense time, as we were not totally confident of the structural integrity of the structure, later inspection of the tower on the ground showed that the basic structure is reasonably sound and will respond to some TLC to make it a very solid structure once again. The cost of replacing the structure was estimated as being $20-30 thousand dollars as it would need a completely new concrete base and footings.
Once the tower was nearly at ground level, the external antenna arms and fittings were removed to allow us to put it on blocks off the ground so it could be worked on. All the cables and odd bits of pipe, clamps and antennas that had been left there from previous incarnations were removed to allow work to commence on the structure.
(Below) Dean removing the outrigger antennas and clamps, the mast is still being held by the crane at this time.
(Below) Tower peacefully resting on blocks and bricks ready forwork to begin.
The work begins in earnest.
The tower will now need to be scraped down, and all the loose rust an old paint has to be
removed, all the bolts will be replaced and the various sections separated and the mounting pads checked for their integrity. There are bent sections of the mast from when it was dropped pre 1970’s that need to be checked and straightened. We will be using quarter power tools to accomplish this, in some cases the pipe or steel section may need to be replaced and checked for any fractures.
This is where our members come in – we need people to scrape, sand, and wire brush the
structure to remove all the old material, once that is done then the metal needs to be painted with rust converter (in this case phosphoric acid) so care will need to be taken and the correct protective equipment must be worn, such as safety glasses, gloves, protective overalls. To this end the Club will / has purchased disposable overalls, nitrile gloves (acid proof) and sets of safety glasses for those who will help in this project. If you have your own PPE gear, then it would assist us in this process. The type of tools required would be wire brushes, rotary wire wheels, spanners and shifters etc and anything that can be used to complement the job at hand. The tower is large, some 40 metres long and the legs about 3 – 4 metres apart at the base, so we are going to need plenty of people to assist us.
A new cable tray ladder is to be fitted to allow all cables (new and old) to be secured to the
tower in a proper manner, so that the vibration and personnel that are fitting and maintaining antenna’s etc will not damage them, lightening protection devices are to be fitted along withproper earthing of the tower to promote safety and longevity of equipment. Most cable to be refitted will be new, the main cables will be LDF5-50 thus providing very low loss and better performance of the systems on site. New antenna’s for the remote HF site project and a new main professional multi band array at the tower top for our Amateur services are to be fitted.
We will of course be limited by the vagaries of the weather, so there will be days when no
work can be performed or some that may get cut short, and we do not want to burden those older members with strenuous tasks, so the more the merrier. Once the tower has been cleaned, repaired and rust converted and primed, it will be ready for the main 2 pack epoxy coating to go on.
This will be performed by a commercial company that specializes in this type of work, they
assure us that the coating will last for a minimum of 20 years in this sort of environment, so that makes us feel that the job in hand is worth it.
A time line is being generated for the repairs, this will be circulated around all members on
a regular basis, if you can help us, then please volunteer some of your time so we can get this back in service ASAP.
I will send updated circulars to all members with photos and information of what has
happened so far, there will also be a map as to the location of the site. Please be aware that as this is on private property, so we do not want persons to randomly enter the property, but you will be welcome on work days when a supervisor is on site.
Please send your contact details to Trevor Molde VK5NIX, preferably by email to :-
firstname.lastname@example.org or phone: 82350634 and leave a message. Trevor has asked that you make sure you identify you message as being for AHARS so it does not get lost in his junk mail.
Thanks Barry VK5BW.
The following photos are an idea of some of the typical work to be done....
Clean rust, paint, etc off, replace bolts, rust convert and prime surfaces ready for coating.