revamping the tower for a bigger 6mtr system

[VK4ABW]

Finally got around to taking a few photos of the rebuild.
photo 1 is the new turnstile. You take a flywheel from a ford (the only good part) weld it to some steampipe and then carefully craft a platform around it. Add 4 wheels for it to turn on and 3 arms for the cables to tie to.


photo 2 is the head of the new inner tower. Spend about 6 weeks scratching your head working out how to create a rotating system with 6,650kg of torque and then about 5 minutes to build it (or it could be around the other way).


photo 3 is a side view of the rotating system. A lot of patience is required to make something like this work. The pink rotator is a brand new Diawa 500kg rotator (acquired thru an auction) with the 28volt AC motor removed and a 12 volt DC motor installed. A few cog swaps made it all work. The reason for changing to DC is because no controller was found, plus my shack already has a 12 volt DC controller set up for EME. The mechanical stop inside the Diawa 500 has been removed to allow it continuous revolution. 13.3 revolutions equals 1 revolution at the top. About 36 minutes for 360 deg rotation which i very rarely do. The system spends most of its time going from the pacific window to the EU window which equates to 12 minutes rotation. The bottom rotator has been stripped of everything inside except the readout system. This is its only function.


photo 4 shows the new 9 meter long H frame cross arm. Inside it is a 25mm thick walled pipe which is driven from the center for elevating the two vertical arms of the 6 mtr system. Each arm will be 7.5mtrs long with a 17.8 mtr long, 13el 6mtr yagi at each end. Yes folks, count them.....that's four 13el yagi's on 6mtrs. Should crack the 20db mark with these.


photo 5 shows the two KR500s being put to good use. The right hand one goes through a 6-1 reduction resulting in 30 degrees of elevation for the 6mtr system. The left KR500 rotates the 2mtr system which has dual hinges on the cross arm. A cross brace between the uprights will join them and from here it attaches to the upright threaded rod. Full adjustment is possible for upto 90 degrees elevation.

another angle of the two KR500s


Hopefully in a few weeks i will have finished cleaning up the outer tower (the green tower behind the trailer)(needs painting again, plus a good winch system installed) and will be standing it back up. A 10 tonne crane does the job nicely

Stay tuned for pictures of the monster yagi's being fabricated.......

de Gary
VK4ABW
Working more with more

[VK2KRR]

Hi Gary
Have I not said before that your crazy ?
Anyway Im glad, be good if there was more crazy amateurs out there.
Awesome bit of engineering and ingenuity, im impressed. Well done. Keep us posted.

[VK6ADF]

Hi Gary....nice photo's. Hope you post some more once its up and running.

73 Phil...VK6ADF

[vk3six/a]

Hi Gary
Have I not said before that your crazy ?
Anyway Im glad, be good if there was more crazy amateurs out there.
Awesome bit of engineering and ingenuity, im impressed. Well done. Keep us posted.

Reminds me a bit of Jimmy Treybig in Austin 4x4x65 footers.
It remains to be seen what you work extra on 6 in the coming cycle.
So if you think its all about antenna and not operating skills,,
If you work W6JKV/5 you have the world eme record.
Try that for starters.

(I'm talking clean un-enhanced two way cw, no data no DSP).

Nothing succeeds like excess.

[VK4ABW]

As promised. a picture is worth a thousand words.

[VK2KRR]

Gary
A picture is worth a thousand words.... but 3 photos is worth 3000 words
So come on now a few more please
And perhaps you could add some words too to let us know about the new system and its construction.
Looks really good. Hows it working?

[VK4ABW]

Seeing as Leigh asked so nicely for more photo's, here they are.
This photo shows a closer view of the main tower, turnstile, crossarm and associated cabling. At this stage, the tower has only been extended 2 meters.


If you look closely, you will notice that there are 2 brackets at mid points either side of the crossarm. These are for the 4 x 17el 2mtr system which will be installed at a later date. The silver KR500 will elevate these antennas.

This photo is another angle of the whole array, again with the moon in the background.


The main feedline is 50mtrs of LDF5-50 with 2 new Andrews N connectors attached. This then feeds into 14mtrs of high grade 10dfb cable which plugs directly into the 4 way power combiner. From here, Andrews LDF1-50 goes to each beam which consists of a hairpin and 1/2wave balun for matching. The beams were individually tested for swr and peak noise @ 9mtr agl before being attaching to the main uprights. Then, each side was individually assembled and elevated against the side of the tower for ease of finishing alignments (overhead cable stays). The cross arm was then lifted and chained to the side of the tower at 4mtrs agl for final assembly of the side uprights. Each side was pre staged with ground stakes (to stop them sliding) before lifting against the crossarm for final attachment. 2 x 3/4" bolts hold each 10mtr vertical arm in prefabricated thick walled steel 'C' channels. These are turned through double bearings at each end of the 9mtr cross arm and driven by a centrally located 6-1 reduction system. The central pipe for turning these monsters was fabricated from 28mm thickwalled high tensile pipe which 'floats' through another pair of 2" bearings, and is also reinforced with 3mm thick right angle steel either side (to reduce lateral twisting). There is still a small amount of lateral twist (well within acceptable limits) but then, this is better than having it too stiff and failing.

A 2.4ghz wireless camera has been installed on the central elevating pipe for remote viewing and alignment with the moon.

System dimensions are 17.8mtrs long, 8.3 mtrs high, 9.3 mtrs wide with a total weight of approximately 200kg.

permission is required before copying or reproducing these photographs for any purpose.

[VK4RF]

Wow Gary... You should not have used the Crop King Fertilizer on your 2mtr array and tower... Look what it has done.. All jokes aside. A very impressive job you have done there for sure. Thanks heaps for the pics as well.

[VK2KRR]

Thanks Gary, great stuff. Its hard to get an idea of how big the actually are from the photos as there is not much to compare too. But good work. Got any on air performance results for us yet ? made any contacts ?

Keep up the good work there its great to see.

[VK4ABW]

Thanks Gary, great stuff. Its hard to get an idea of how big the actually are from the photos as there is not much to compare too. But good work. Got any on air performance results for us yet ? made any contacts ?

Keep up the good work there its great to see.

I will have to get my son to take a photo of me standing in the middle. This may just provide the 'scaling' factor your after what can i say....its bloody big.

No takers last night but the weekend provided some light entertainment through working England, Italy, Spain and Faroe Islands. I have a G and a D station lined up for tonight and i'm chasing the T61 as well (although i've worked there already).

I'm hearing and working many stations well below the -20db mark with no pre amp....just the ic756pro3. Even whilst working the G i could easily see ZL3 and G5 working 500hz up the band. What a treat Many stations including the OY3 station (7el yagi) are now 'audible' in my speaker. My best so far is -15db with the speaker jumping all over the place.

I haven't worked any US stations with this system, but the emails are arriving, so maybe on the weekend with a rising moon will give me something to do. I've already worked most of US with the old system but they want to work me again

TEP sounds totally different too. Last night i was comparing my trusty 11el yagi @ 125ft agl against the system and it was chalk and cheese. The 11el produced 4 clear traces on 49.750 and the array produced 15 traces on spectran. I also followed the TEP window as it swung from 325 to 340 deg and then back to 330deg.

Hoping to explore more TEP when it is cranked to full height.

cheers
Gary

[VK4WDM]

This worrying thing is that I am only 25k from Gary. Thankfully I will be downwind when he is beaming Europe. If he decides to try long path I will hang a few raw chickens on my tower and they will be nicely BBQed in no time!

Seriously though, Gary always has a nice clean tight signal and causes much less QRM than some of the over-driven, poorly ajusted stations that boom in here from time to time and manage to splash over most of the band.

73

Wayne

[VK4ABW]

This worrying thing is that I am only 25k from Gary. Thankfully I will be downwind when he is beaming Europe. If he decides to try long path I will hang a few raw chickens on my tower and they will be nicely BBQed in no time!

Seriously though, Gary always has a nice clean tight signal and causes much less QRM than some of the over-driven, poorly ajusted stations that boom in here from time to time and manage to splash over most of the band.

73

Wayne

gee thanks mate...... will come over 1 weekend for some BBQ chicken ... ABW style

Have done a rough plot of the pattern and she is very clean. Side lobes down 33-35db, F/B 21db and main lobe 3db point is 8 degrees. Main lobe in the 19.6db range. Makes tracking the TEP very precise. I use my single 11 to do a precursory check of the main direction, and then crank the array that way for fine tuning.

Logging many more indicators now and very accurately with the IC7700 too.

Don't be a stranger and call in sometime for a guided tour

Gary