Just Sharing This Coming to a forum near you soon - mobile dish test rig

A

a33

Specialised Contributor
Messages
598
My Satellite Setup
XSAT410
Rebox RE-9000
My Location
NL
@PrvtN00b :
Well, I assume there ARE dishes out there with accurate position for the LNB holder and proper LNB-aiming.

But as this is (just) an assumption, measuring and checking is very usefull, when you want to get the most out of your dish!

For a paraboloid dish (parabolic both vertically and horizontally) with a flat face, the best way to measure it is finding three measures: hight and width of (the working area of) the dish, and exact depth at the middle; and then let a calculator do the work.

Parabola6 by Strannik is a good calculator, and so is my calculation spreadsheet (results for CM180 shown in an above post).
Don't use Parabola Calculator 2.0 though, or the Satsig calculator. They use the deepest point measurement for calculation, which in theory is OK (see also my calculator), but these two calculators alas give wrong outcomes!


Knowing the exact offset angle of your dish also gives you the opportunity to set the dish elevation by measuring the angle of the dish face. That is very usefull when setting declination towards due south/north, with no satellite at exactly that direction.

Greetz,
A33
 
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Channel Hopper

Channel Hopper

Suffering fools, so you don't have to.
Staff member
Messages
29,121
My Satellite Setup
A little less analogue, and a lot more crap.
My Location
UK
in other words, we are not even using the full potential of these dishes at all??

thanks.

The CM design, like many others have no user adjustments because they have been tested and approved for use in the VSAT industry for receive/transmit purposes.
John's dish, whilst using the same reflector has the consumer type feedarms and clamping, I doubt the manufacturer is at fault, but it might take another user of the same model to confirm this.

If somebody on the forum does own the commercial version with the separate backplate and single boom, and takes measurements in a similar fashion, then it could provide some reassurance.
 
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John

John

Enthusiast.
Messages
2,429
Location
North Nottinghamshire.
My Satellite Setup
Elite 2.2 PF - CM1.8 - CM1.2 - Gibertini 1.25.
Ku - Ka -C & Ext C.
PC cards-TM5402 receivers.
Promax FSM.
My Location
North Nottinghamshire.
Finished tweaking illumination mapping on the 1.8 CM using stock arms and stock non adjustable plastic lnb holder but had to alter fixing points and lengths of side arms to achieve this. Awaiting Rimants Inox adjustable lnb holder which will help enormously for future change-over of different lnb's / feeds for different bands.
Have got all the ref: measurements dialed in correctly - which is not a 5 minute job, as opposed to the stock measurements. Here's a quick vid showing present mapping with a hand turned laser pointer in the lnb holder slightly loosed off - which causes a bit of pointer shake as i alter my grip on the protruding 40mm tube out the back of the lnb holder but you get the idea.
Apologies for dish washer noise at the end chucking it's water out into the nearby drain and the setting afternoon sun that didn't help with the lighting of the operation.
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RimaNTSS

RimaNTSS

Super Moderator
Staff member
Messages
4,975
My Satellite Setup
Some SAT-related hardware.
My Location
N-E from Riga
Seems that you made video Private, so, it is not possible to see it, at least at my end.
 

Attachments

John

John

Enthusiast.
Messages
2,429
Location
North Nottinghamshire.
My Satellite Setup
Elite 2.2 PF - CM1.8 - CM1.2 - Gibertini 1.25.
Ku - Ka -C & Ext C.
PC cards-TM5402 receivers.
Promax FSM.
My Location
North Nottinghamshire.
Seems that you made video Private, so, it is not possible to see it, at least at my end.


I'll double check Rimants and alter it
 
John

John

Enthusiast.
Messages
2,429
Location
North Nottinghamshire.
My Satellite Setup
Elite 2.2 PF - CM1.8 - CM1.2 - Gibertini 1.25.
Ku - Ka -C & Ext C.
PC cards-TM5402 receivers.
Promax FSM.
My Location
North Nottinghamshire.
RimaNTSS

RimaNTSS

Super Moderator
Staff member
Messages
4,975
My Satellite Setup
Some SAT-related hardware.
My Location
N-E from Riga
Much better now @John . I am just wondering if you are shooting the movie, who is moving in front of the dish? :confused Just kidding. Please continue!
 
Channel Hopper

Channel Hopper

Suffering fools, so you don't have to.
Staff member
Messages
29,121
My Satellite Setup
A little less analogue, and a lot more crap.
My Location
UK
Good thing you don't have cats.
 
John

John

Enthusiast.
Messages
2,429
Location
North Nottinghamshire.
My Satellite Setup
Elite 2.2 PF - CM1.8 - CM1.2 - Gibertini 1.25.
Ku - Ka -C & Ext C.
PC cards-TM5402 receivers.
Promax FSM.
My Location
North Nottinghamshire.
John

John

Enthusiast.
Messages
2,429
Location
North Nottinghamshire.
My Satellite Setup
Elite 2.2 PF - CM1.8 - CM1.2 - Gibertini 1.25.
Ku - Ka -C & Ext C.
PC cards-TM5402 receivers.
Promax FSM.
My Location
North Nottinghamshire.
... 1st day out for the new kid on the block using ref: measurements for feed positioning & illumination mapping.
Pretty good results with no tweaking apart from skew & considering the lnb and most of the dish is only 150mm off the ground so subject to some ground noise perhaps - looking at 63° West data using a cheap 'Blazer' pll universal lnb for about £8.
...........................................................................................................................................................................................................................................................................................................

1.8 Test rig A - 63 West data - reduced..jpg1.8 Test rig - 1st day on duty. - 63 West. - - reduced,..jpg1.8 Test rig - - 11.590 - reduced.jpg1.8 Test rig - 63 W 11504 - reduced..jpg
 
John

John

Enthusiast.
Messages
2,429
Location
North Nottinghamshire.
My Satellite Setup
Elite 2.2 PF - CM1.8 - CM1.2 - Gibertini 1.25.
Ku - Ka -C & Ext C.
PC cards-TM5402 receivers.
Promax FSM.
My Location
North Nottinghamshire.
... This little box turned up today for use on the mobile test rig

...............................................................................................................................................................................................................................................................................................................
Inox holder. - reduced...jpg
 
John

John

Enthusiast.
Messages
2,429
Location
North Nottinghamshire.
My Satellite Setup
Elite 2.2 PF - CM1.8 - CM1.2 - Gibertini 1.25.
Ku - Ka -C & Ext C.
PC cards-TM5402 receivers.
Promax FSM.
My Location
North Nottinghamshire.
... It's one of Rimants Inox adjustable lnb holders.
A very nicely made holder it is too.
.............................................................................................................................................................................................................................................................................................................
Inox lnb holder. - reduced..jpg
 
P

PrvtN00b

Member
Messages
25
My Satellite Setup
2.4 PF, 1.8 Raven Offset and 1.2 offset for DTV
My Location
Panama Central America
... It's one of Rimants Inox adjustable lnb holders.
A very nicely made holder it is too.
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View attachment 126413
The best, I have a few of them over here in Central America, Panama, made by RimaNTSS
 
John

John

Enthusiast.
Messages
2,429
Location
North Nottinghamshire.
My Satellite Setup
Elite 2.2 PF - CM1.8 - CM1.2 - Gibertini 1.25.
Ku - Ka -C & Ext C.
PC cards-TM5402 receivers.
Promax FSM.
My Location
North Nottinghamshire.
... I thought i would make better use of a 1.2 mtr Precision PF reflector that was hanging about in the garage along with the 1.8 CM reflector before it got grafted onto the Test Rig set-up.
Iv'e knocked up a 'quick release' idea to attach the 1.2 in front of the 1.8. Iv'e got some Ku to Ka feed experiments to look at soon and the 1.2 Precision is an ideal candidate.
As the Test Rig is a purely functional device, cosmetics don't come into it.
I started off by quickly fabricating two side brackets to attach to the upper side points of the 1.8 CM - the rest should be easy to follow from the pics.
.................................................................................................................................................................................................................................................................................................................
Test Rig 1.2mtr Precision quick fit - - reduced..jpgPrecision back bar ... reduced..jpg1.8 to 1.2 quick release piggy back.jpg1.8 to 1.2 quick release piggy back - reduced..jpg
 
nelson_b

nelson_b

Contributor
Messages
1,714
My Satellite Setup
Strong 4375 driving 1.8 C.M. offset + Inverto Black Ultra twin + BSC 421 and Zinwell C band l.n.b.,s - DR HD F15 - TM5302 and Skybox/Openbox M3 - HD receivers.+ other dishes in use - 2.4 CM offset - Alcoa 1.8 P.F. - C.M. 120.
My Location
north west yorkshire
Yes .... Liking it .... :cool:
 
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