Mossie

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MossieNet

Hi All

So early Feb 2007 I decided to put up my 11M Ham tower as I had no Loss to the New commissioned WP High Site and I had been disconnected from Jawug for about 6 months ;(

So I got my Garden executive to dig me a hole in the back garden of 1M x 1M x 1M this was the size of block needed to support a 12M freestanding tower.

After the hole was finished I sourced the reinforcing needed to support the block as the stresses that nature creates on the tower can be vigorous on normal days and Johannesburg is known for its stormy days.

so I got one of these to do the job:

Image:Reinvorcing1.jpg

Reinvorcing 2:

Image:Reinvorcing2.JPG

Then I moved on to lightning Protection as the lightning in our aria is very bad and ban be alarming to hear in the middle of the night. We have has very bad and close strikes so I was not taking any chances as lightning damage is not a nice thing.

lightning rod 1.2M long (I put 9 of these in) they are all connected with 5MM copper cable: .. Image:Lightning protection1.JPG .. Image:Lightning protection2.JPG .. Image:Lightning protection3.JPG .. Then these bolts are 1.5M long and goes in to the concrete to bolt down the tower. The round bar at the bottom stops the bolt from being pulled out of the concrete block. .. Image:Main Bolts.JPG .. This is the bolts Mounted in to the reinforcing and you can see the earthing also wrapped around the bolts for extra safety. We taped up the tread of the bolts so no concrete can get in there. .. Image:Ready for concrete1.JPG .. Image:Ready for concrete2.JPG .. Image:Ready for concrete3.JPG .. Image:Ready for concrete Earthing cable.JPG .. Image:Ready for concrete Main Bolt secured.JPG ..

And then we wait 28 Days....

Image:Driedblock.JPG

So after the agonizing 28 Day wait and planning the day to put up the tower came, we organized a WUGMEET at my place so the guys could see what happens and for extra brandy and hands :) to make light work.

Here is the T-Piece that allows you to lower the tower this also is the weakest link on the whole setup so it is really overkill to make sure it is as strong as possible, the Tower is already bolted on to the T-Section ready to be lifted in to place.

Image:T section4.JPG

Image:T section5.JPG

Image:T section6.JPG

Here you can see how the Hinge mechanism works between the T-section and the Tower.

Image:Hindge.JPG

Then the Big day arrived, the weather was a bit cold and overcast but all the guys pitched and where ready to get this tower off the ground :)

Image:Lifting1.JPG

Image:Lifting2.JPG

Image:Lifting3.JPG

And at last she is standing!!!

Image:Ltighten Bolts.JPG

After the tower was up I had to fit the back bolt and secure all the other bolts.

Image:Tighten Bolts2.JPG

Then Later the afternoon (nice and shinny) we installed the antennas and got me connected to Jawug :-) (this was on 2007-03-24)

Image:Installing Kit.JPG

Exactly 2 years, 1 month and 1 week later

I decided that I want to go up to 19m as I want to pull in a redundancy link to Platberg and I also want to link to Potch.

So here we go again :0)

I phoned WEBB and was told if you want to do a 21M freestanding tower you need a base of 1.5x 1.5 x 1m (deep) concrete block.

so I opened up my block and added a 1m deep by 300mm wide ring around the existing block with reinforcing.

so as it is no my block is 1.6 x 1.6 x 1M (deep) and I will only be going to 19m so all should be fine :)

Image:Bigger Block T-Section.JPG

Here are the new meterial that will be used to build the 2 new sections 1 x 6M section and 1 x 2M section.

Image:Materials New Section.JPG

Image:Materials New Section2.JPG

To lower the tower I did not want to risk using manual labour as I do not want to deal with lawsuits if someone gets hurt for being stupid so I decided to use ropes and pulley to lower the tower. this system has been used with good success but it seems my luck was out :-(

Here is the sling setup:

Image:Sling Pully.JPG

We used 2 ropes but only had one pulley so I put one rope through the pulley and the second rope through the shackle next to the pulley all seemed fine and I loosened the back bolt on the tower and pulled her over so she could hang on the ropes. at this stage all seemed fine and the tower was leaning forward at about 80-85 degrees.

I the gave the go ahead for the bakkie to move forward and this would then lower the tower nice and slowly but the tower moved forward and kept moving forward but the Bakkie was standing still..... then I heard the big ****SNAP**** noise and the tower came crashing down ..... BANG........

then I saw this:

Image:Snapped Ropes.JPG

both ropes snapped at the same time at the same place ( somewhere between the pulley and tower) the part of the ropes that snapped never went through to pulley or shackle...

this is a stand I use to lower the tower on to so that the antennas do not touch the ground, it broke the fall off the tower. Here you can see how it is bent.

Image:Bent tressile.JPG

Image:Bent tressile2.JPG

so we then took a big sip of brandy and then carried on with the work that had to be done :-)

Loosened the rest of the bolts:

Image:T section3.JPG

Image:Top of tower2.JPG

then to make it easier to work and move the tower around we split it in two by loosening the bolts on these sleeves:

Image:Spliting Tower.JPG

Image:Spliting Tower2.JPG

To make it easier to build the new section we bolted the new pipes in between the 2 old sections and made sure all was straight:

Image:New Section.JPG

Image:Lining up Tower.JPG

Image:Lining up Tower2.JPG

Image:Lining up Tower3.JPG

Here you can see the new Sleeves used to connect the new section to the old section:

Image:Sleev joining sections.JPG

Here are some pics of the fabricated tower all is build and welded just needs some nice paint:

Image:Finished tower.JPG

Image:Finished tower2.JPG

Image:Finished tower3.JPG

Image:Top of tower.JPG

-)

updates to follow