On the scrounge again..Copper feed construction

[Vipersan]

Ok ..started my all copper Ka feed ..and looking promising so far.
I have obtained about a yard of 12mm hard copper tube internal diameter approx 10.5mm
I have cut a disc of solid copper on which to build the concentric ring cone ..(I'm sticking as close as possible to the inverto dual ka feed design.)
cutting 2mm thick hard copper is no picnic ..and drilling it !! ..well don't ask ...take it from me it's far from easy.
Anyway started to assemble the concentric rings ..
A short section of 15mm water pipe is perfect for the first ring ..
All others will have to be made by reducing standard copper pipe sizes ..
To do this I hope to cut sections out of the side of the rings ..
for example ..
I shall need to reduced the diameter of the second ring as shown in the photo by 1mm..
so the 22mm copper pipe section will have a 1mm cut in the side and the gap closed ..errr..hopefully.
Which leaves the 3rd and 4th rings..
25mm OD and 32mm respectively ..
To do this I'm hoping to get my hands on some 28mm and 35mm copper pipe offcuts ..
Problem ..I can't source any..
Anyone out there have any suitable offcuts they'd like to sell me ..
Either the correct outside diameters ..25mm and 32 mm (not hopeful)..or maybe 28mm and 35mm ..which do exist.

Please ..can anyone help ?
rgds
VS

 

[PaulR]

Here in France, instead of 15mm pipe there is 14mm and 16mm - does that fit in with any of your plans?

Also - have you thought about the sleeves that would be used to connect pipes. They would have the ID to match the OD of the pipe.

 

[Vipersan]

Here in France, instead of 15mm pipe there is 14mm and 16mm - does that fit in with any of your plans?

Also - have you thought about the sleeves that would be used to connect pipes. They would have the ID to match the OD of the pipe.

I did consider them Paul..sad to say Most of the available sizes I need require reduction by between 1 and 3mm ..so using the slightly wider diameters of the jointing sleeves would only make it more difficult ..
If the joints went inside the pipe rather than outside ..then it would have helped.

Having said that ..possibly the outer jointing piece for a 22mm diameter pipe would be 24 mm ..and if I could stretch it 1mm ..then at least I could make the 3rd ring 25mm..
Maybe it would stretch if heated and drived hard onto a ring resizer ...
If I had one that is..

cest la vie

 

[Vipersan]

Looks like cutting a section out of a standard sized ring of copper pipe might be viable ..but wouldn't want to do a reduction of more than 2mm ..as the chances of retaining circularity would be seriously impaired.
But..I have managed to reduce the 22.3mm ring to 21.2 ..and am happy this is close enough ..
All a learning process anyway ..and might well all be for nowt in the end.
lol

 

[pride21]

hi VS how about straight connectors i just measured one slightly over 25mm or a bend measured at 26mm all outside diameters.

 

[Vipersan]

Yep ..a straight connector or bend might well do ..(non yorkshire type) ..for the 3rd ring.
I'll have to pay my local plumb centre a visit.
Still struggling for ring 4 tho'

 

[Analoguesat]

Any houses being gutted & refurbished nearby? You often see odd lengths of old no doubt imperial copper pipe sticking out of the skips

 

[Vipersan]

Had no luck finding offcuts of pipe to make the 3rd and 4th rings ..
Yes I can yet such stuff on ebay ..but the greedy sods are wanting about £4 for 4 inches of pipe ..and another £3.80 to post it..
I aint playing ball ..
So am having a go at making 'em myself from flat 1mm copper ..
Cut a strip from the edge of a flat plate ..and attempting to curve around a wooden pole..
getting there I guess ..
This is the larger outer ring which needs to be 32mm OD ..
I'm currently at 35.5 mm ...and closing ..
errr pardon the pun..

How I suffer for my art..
Copper being a good heat conductor ..so have to keep stopping when my fingers get too hot ..and letting the job cool.
Where would I be without my beloved Dremel.
lol

 

[Vipersan]

Not perfect ..but close enough for me ..
Tomorrow I'll start construction of ring 3 ..
Ring 4 is 0.1mm wider than perfect ..but who's counting.
lol
rgds
VS

 

[Vipersan]

Got bored ..
Nothing on TV to interest me ..
So carried on with the third ring ...
Not a perfect circle as you can see from the photo ..but in my defence it gets much harder as the diameter gets smaller ..
Still ..at least I dont have to make Nine ..
So middle earth is safe for the moment.


Ash nazg durbatulûk, ash nazg gimbatul,
Ash nazg thrakatulûk agh burzum-ishi krimpatul.

might try and get it a little more cicular tomorrow..
rgds

 

[Vipersan]

Spin-off time ..
My step drill bit finally arrived ..so put it to use
With a 12mm test drill in 0.75 copper ..
then realised the old single band ku lnb (LO 10600) I recently unearthed might be put to put to some use if Ilop off the feed ..
Then completed the _washer_ I was making with the test drill.
Made to exactly fit in the smallest diameter recess of the feed ..and allowing a 12mm waveguide to pass through the centre..
I calls it my pea-shooter ..cos thats what it currently looks like.
The waveguide will be held centrally with liquid plastic ..and a wider outer sleeve fitted for strength and mounting purposes ..
Eventually being finished off with a WR42 type connector.
...Yes ..I do tend to go off at tangents ..
;)

 

[Vipersan]

..Before I permanently embeded the pea-shooter in the feed ..I figued an extra 3.5cm high ring of 15mm diameter should be fitted..
Too dark to pot it up tonight ..but you get the idea..

 

[Vipersan]

Ok ..not soldered up as yet ..but all the components are ready..
The centre copper waveguide is potted into place ..and a 22m collar fiited to attach the outer sleeve ..which comprises a 22mm to 15mm reduction fitting ..and the open circular WR42 flange has been made ..
The elements will be stacked as in the photos ..then soldered up for rigidity tomorrow..
rgds
VS

 

[Vipersan]

Nothing holding this together but friction ..no soddering as yet.
I just wanted to make sure of reasonable alignment before I soddered it up.
I have to say I'm very pleased ...now fingers crossed it works as good as it looks ..
A couple of tiny bits of copper swarf down at the bottom of the feed ..but I haven't de-burred this pipe yet.
rgds
VS

 

[Lazarus]

Sodd deburring - just get it fitted!

 

[Vipersan]

Sodd deburring - just get it fitted!

Tomorrow G ...assuming the weather permits..
Patience is a virtue m8 ...
I jumped the gun last night and almost lost my expensive lnb to weather

 

[Llew]

Great stuff VS. Can't wait to see how it works out - weather permitting

 

[Vipersan]

So ..preliminary tests didn't bode good ..
Chose Golfe at 16E ...very occasional lock at 5.1db ..which is worse than the FD9000..
Reqires around 7.0 to 7.5 db for smooth video ..
To say I was disheartened was an understatement ...then I remembered how the Ku Gibby feed underperformed until the effects of the funneled concentric rings of the feed were ironed out ..
So out came the aluminium foil and I crudely lined my hybrid feed with it ..
signal levels immediately rose by approx 2.2db ..giving enough signal from Golfe for a almost perfect lock.
I conclude it might be prudent to construct the copper lining I originally intended for the all copper feed ..
Hopefully this will give max signal at the waveguide ...but of course this feed was never intended to illuminate the 1.25 gibby ..

more likely a 90cm at best.
rgds
VS

 

[Vipersan]

Back to the main reason for the thread..
I just hope I haven't over reached my abilities ..
Nothing easy about this ..but have so far managed the outer and 1st inner ring of the feed ..
The build theory works nicely but is getting harder as I progress inwards ..
Damned small spaces.
But one advantage is that the inner rings weren't fabricated so dont require re-enforced steel wire bracing during soddering ..
Will I ever get there ?
Will it even work ?
Lap of the gods of science and engineering I guess.

rgds
VS

 

[Lazarus]

Where there's Mux there's Brass