Mad science time again ..

[mouse3]

Great project.I keep the finger crossed for you Mr. Viprersan.
I like people like You.

Two picture about,hope helps.

 

[Vipersan]

Great project.I keep the finger crossed for you Mr. Viprersan.
I like people like You.

Two picture about,hope helps.

Particularly love the picture showing mesh BUDs ...
No chance of rain being a problem there ;)
What are they pointing at I wonder ...?
Either located on the equator ....or its a SETI project ..

nice
VS

 

[Vipersan]

Hi friends ..
Had a re-think on the plate design ..
Hopefully I can find someone who can provide custom laser cutting of 4mm thick plate ..
Otherwise ...its going to be done the hard way with marking ...drilling and a file..

here's what I came up with ..
The slots in the plate could then be fitted with custom height curved aluminium ribs 2mm thick which could be slid forwards and backwards in the slots to get the required shape scalar feed ..
A big task ..but not impossible..
rgds
VS
aka Doc Brown..
;)

Just emailed the diagram to a company found on ebay ...offering a laser cutting sevice to aluminium plate ...
No idea if they can do the job ...but at least they replied ...

>>Hi

Many thanks for your enquiry. We are able I'm sure to cut one of these for you. I would be unable to give you an accurate quote until we see the template, dimensions, thickness of material etc. You can email this to linda(at)hydramaster.co.uk
Very best regards
Linda

>>

Just have to wait n see now ...for a thumbs up ..and a quote...
rgds
VS

 

[mouse3]

For C band only extension project works,you must fallow only the dish curvature.
For Ku band must be very accurate the extension and mesh perform bad on this frecvency.
The orizontal mesh it s homemade.The dish are located on Oz.

No offence,but town council agree this extension ? Maybee you must become one SETI member first.

 

[Vipersan]

For C band only extension project works,you must fallow only the dish curvature.
For Ku band must be very accurate the extension and mesh perform bad on this frecvency.
The orizontal mesh it s homemade.The dish are located on Oz.

No offence,but town council agree this extension ? Maybee you must become one SETI member first.

errrr ...no ...If/when I get around to making extension wings for the dish ...
They will be removable ...just in case there are objections...
Regardless of the additional diameter add ons ..
The custom feed will go ahead ...
It can only be beneficial to the existing setup ...to maximise illumination..
fingers crossed.
VS

 

[mouse3]

Removing and instaling extension wings are difficult to make by one single person.
For Ku band one mould it s necessary.
Old petalised dish supplier have one mould for dish and one extension mould for wings.Thinks are very complicated.Only one installer have years ago one mould for 3m petalised dish here in my area.
Lots of people failed to install at home 1,8m and 3m petalised dist at home by himself.Tolerance it s about 1mm for Ku band.

 

[Vipersan]

Removing and instaling extension wings are difficult to make by one single person.
For Ku band one mould it s necessary.
Old petalised dish supplier have one mould for dish and one extension mould for wings.Thinks are very complicated.Only one installer have years ago one mould for 3m petalised dish here in my area.
Lots of people failed to install at home 1,8m and 3m petalised dist at home by himself.Tolerance it s about 1mm for Ku band.

Not a lot of choice in this regard ...
The dish was made in the 1970s I believe ...
Alcoa the maker no longer makes dishes ..so obtaining molds or indeed the manufactured petal extensions is no longer an option ..
Since I am working in C band ..I think 1cm tollerance is do-able ...and am only planning to increase the dish diameter to around 2.4m max ..
I've already formed a plan ..sort of ...to create the mold I need ...but thats what experiments are all about ..
..but thats a later project ..
Getting involved with the custom adjustable feed first ...as thats going to be essential ..if the wing project goes ahead.
rgds
VS

 

[Channel Hopper]

Argh! So it should be f/D ratio then, not f/d. I'll try to remember that one.

I was aware of it but I have a horrible feeling that I get it wrong now and then ;)

Worse still, depending on where in the world you are, or the software programme used to calculate, the letters also change (focal distance = distance/distancia focale/e, depth = fond etc.)

 

[Vipersan]

Not a lot of choice in this regard ...
The dish was made in the 1970s I believe ...
Alcoa the maker no longer makes dishes ..so obtaining molds or indeed the manufactured petal extensions is no longer an option ..
Since I am working in C band ..I think 1cm tollerance is do-able ...and am only planning to increase the dish diameter to around 2.4m max ..
I've already formed a plan ..sort of ...to create the mold I need ...but thats what experiments are all about ..
..but thats a later project ..
Getting involved with the custom adjustable feed first ...as thats going to be essential ..if the wing project goes ahead.
rgds
VS

Had a reply back this morning ..re the plate ..
They can provide the 4mm thick aluminium plate ....laser cut it to my specification for £25 plus postage ...
Not bad really for a custom job ...and am definately considering it ..as it will be accurate ..and save me a lot of work..
rgds
VS

 

[Channel Hopper]

Had a reply back this morning ..re the plate ..
They can provide the 4mm thick aluminium plate ....laser cut it to my specification for £25 plus postage ...
Not bad really for a custom job ...and am definately considering it ..as it will be accurate ..and save me a lot of work..
rgds
VS

Sorry, just logged in and saw the thread progression

I've got at least one C band scalar ring here that is of no use to me, and it probably comes complete with a burnt out corotor. Yours if you need.
They are easy enough to modify anyway, the rings can be pulled to bits with a good vice, some small mole grips and a bit of leverage to fracture at the base.

Commercial polariser systems are truly mechanical, the circular types are a long tube with a set of ports cut inside to remove the opposite polarity. The pin drive and stepper motor in domestic systems do not have the correct VSWR for the stringent applications required, even on a receive only system, and so the co-polariser system is nothing more than a convenience product, jack of all trades but certainly no expert in any.

 

[Vipersan]

Thanks CH .
Will probably take you up on that ...
But still going ahead with the adjustable feed I designed ..
Just waiting for a final price from the Cornish Ally cutting company.
Its certainly a company I'll bookmark ...and might be useful to other group members as they seem willing to help with cutting all sorts of ally shapes ..and occasionally members aquire incomplete dishes etc.
rgds
VS

 

[Vipersan]

Some progress on the custom plate from Hydramaster ..
I sent them a rather crude additional 'paint' drawing of how the ribs would fit into the custom plate posted earlier in the thread ..
They agreed to cut the ribs which I will have to curve and cut slots in.. to fit myself ..as part of the package ...and the circular plate ...for a total of £30
all in.
Not bad at all for a custom laser cut project ..
I will of course post a picture of the plate when it arrives..
here in the meantime is the crude second drawing I sent them ..
rgds
VS

 

[Vipersan]

Today I'm a very happy bunny ..
The custom plate I designed and had laser cut from 4mm aluminium plate has arrived ..
Now I just have to make the scalar ribs ..a mount ring ...fit them and make it work ..
A project I'm going to enjoy ..
I just hope it results in a better illuminated dish..
Nice job though ..I'm impressed with the workmanship..
rgds
VS

 

[Vipersan]

....In the begining ...there was cardboard...
Hopefully the cardboard template ribs will eventually become aluminium ribs .
The strips of 2mm thick ally have been cut ...and using the templates ...curved to fit ..
For this process I'm going to have to make 3 x disc shaped blocks of wood ..exactly the right diameter ...in order to form the aluminium strips into rings ..
The positions of the cuts and lengths will be pre determined by following the templates ..
Then gently heated and hammered to shape around the wooden circular blocks ..
Well ..I think the idea speaks for itself ..
Any suggestions or advice at this point would be more than welcome ...
VS

 

[Huevos]

Then gently heated and hammered to shape around the wooden circular blocks ..

No need to hammer anything. If you roll the ali around the block and clamp it, the heating alone will make it lose its memory. 2mm is pretty thick though, and wood is not ideal because you need a decent flame (like a plumber's blow torch) and that will mark the wood.

 

[Vipersan]

Thanks for that Huevos ...
yes it is a bit on the thick side at 2mm ..
Not so much worried about the destruction of the wood ..so long as it holds long enough to get the shape ..without bursting into flame ..
They will hopefully only be used once ..if I get it right ...
I could help retard the heat conduction by wrapping the circular block outers with aluminium or copper tape
rgds
VS

 

[Vipersan]

..Good job I'm not in a hurry ..
So far its taken about 10 hours ..glueing and cutting ..sawing and rasping to get fairly close to completing the centre former..
Problem is that I have to keep stopping ..
My 'complaint' wont allow my hands to function with the rasp for more than an hour at a time ..
It's at times like this you wish you had access to a lathe ..

Remember this is the smallest former ..
2 more to go after this ..each successively larger ...
And no guarantees at the end of it ..that it will work ..
But at least I get to test on the smallest first ..which should be the hardest scalar ring to form ..
Had no choice but take a break ..my hands forced the issue ..
So figured a good time to post progress pics
rgds
VS

 

[Huevos]

Haven't you got a jigsaw?

 

[Vipersan]

Haven't you got a jigsaw?

Hi Huevos ...
I _did_ have a hand held reciprocating type jigsaw ...but sadly it died recently ..
Not sure how accurate it would be anyway ...as the tip of the blade might wander over a length of 6 >7cm ..
Idealy a band saw would have been better ...but don't have one of those ..
So use a table mounted circular saw to reduce the square block down to a rough disc by lopping off the corners and angles ...then went on to the rasp and a set square ...
It works but is slow ..
rgds
VS

 

[Vipersan]

Fingers crossed ...I've been speaking to a neighbour today who's 85 year old dad ..previously a keen woodworker ...has a lathe in his garage ..
Big burger ..and non mobile ..but if its still in working order ..ya never know ..
;)
rgds
VS