The Big Lift 2

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Sunday 22-6-2014. On day four, I lost patience with waiting for the concrete to gain full hardness. Justifying the risk of damage as very low thanks to the depth of the concrete and the excellent balance of the dish relative to the pole. I had also used a strong mix of 3.5:1 of premixed sand and gravel (Dansk: støbemix) to cement.

Now I had to find a safe way to lift the dish to mounting level working alone. My wife had helped me lift the 1.8m fibreglass dish by sliding it up a gently inclined ladder. The 2.2m dish was much larger, even heavier and the necessary lift much higher.

First I lifted the weight of the dish off the slotted angle stand using a [2 x 4 pulley] block and tackle. This was supported by two builder's folding stepladders straightened out and tied together at the top. These ladders have the advantage of strong supporting crossbars for the rubber feet. This makes them very stable even when subjected to side loads. Using normal ladders would have been suicidal!

The first image shows the dish lifted off the stand and lowered safely to rest on the ground. I had to be careful to avoid damaging the LNB but it all went well. It had been blowing a gale all day and it suddenly shifted to the East. Making for a few anxious moments as the dish swung gently between the ladders.

The second image shows the rear view as I dismantled the slotted angle, trapezium stand. This was to make room for the ladders to move backwards to the pole. This involved stepping each ladder backwards in turn with the dish slung between them. Finally I was able to move the rear ladder behind the pole and the waiting alt-az mounting.

I don't have images of the actual lift because I was too busy hanging onto the lifting rope and running up and down the ladders.

A double lift was necessary to get the dish high enough to bolt onto the alt-az mounting. This was just a matter of lifting the dish as high as it would go and then tying it off to the tops of the ladders. The block and tackle could then be released, lowered and retied to the dish on much shorter ropes. Allowing the dish to be raised by another foot or so [30cm] on the second lift.

I was lucky and the top edge of the dish just fitted under the peak of the two ladders when the dish was at its highest.

 

I had planned to use a strong ladder, resting on the stepladders, if necessary to get the extra height. In retrospect, I could have set up the ladders over the pole and rolled the dish between them. As I had to lift the dish off the stand first I decided to walk the ladders instead.

Here the altitude pivot bolts have been screwed through the eyes and into the outer ends of the horizontal mounting channel.

The altitude nut has been adjusted to tilt the dish back to point upwards at 25 degrees for Astra 2 at 28E. The dish angle was checked with a digital clinometer laid against a stiff pipe touching the top and bottom lips of the dish.

The Kathrein alt-az mounting is a simple, but very strong, welded construction. Made from two channel sections of steel then galvanized. The two U-bolts hold the mounting to the pole. While allowing the dish to be rotated on the pole to point to the satellite. The nuts can then be tightened to lock the dish firmly on target.

The dish seems to have shrunk now it is tilted back at 25 degrees and raised on the pole. It looked much larger when nearer the ground.

I promise to tidy up the junk from the previous steps. It doesn't look like it now but this is a 2.2 meter dish. [About 7'4" in diameter]

The bottom of the dish is presently 85cm or 33" above ground level. This will reduce by a couple of inches when the soil is levelled and re-grassed. The garden slopes away from east to west by a couple of feet [60cm] over its 30 yards/metres width.






The 4.3" [110mm] heavy, galvanised pipe has been sunk into a meter depth of concrete. [about 3'3" in old money] The square hole was tapered outwards at the bottom and had a minimum cross section of 40cm x 40cm. [16" x16"]

I tidied up the top of the concrete (above ground level) with a ring of cardboard. This had been lying around looking for a purpose. It will probably disintegrate over time.

By this means the last of the concrete mix was raised above the ground without the risk of a frost heave overhang. Untidy hole edges have a habit of allowing a larger lump of concrete to form than the hole itself. In a hard frost the overhang can actually lever the concrete block out of the ground.

The soil will eventually be levelled around the pole and re-grassed for a neater appearance.

Click on any image for an enlargement.

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