Measuring angles

RimaNTSS

RimaNTSS

Super Moderator
Staff member
My Satellite Setup
Some SAT-related hardware.
My Location
N-E from Riga
Hi! I have idea to make some device to be able to measure vertical leaning angle of satellite dish very precisely, I mean with precision 0,01*. I have digital protractor which provides 0,1* precision. But what if I need 0,01*? So, purely mechanical tool, at least 2,5 meters in lengths. Do some of you have experience making such a tool?
 
Drawing: If H=2,5m and A=1mm than angle Y=0,04*
From school times we remember that A=H*sinYScreenHunter_158 Feb. 06 22.28.webp
 
I've got parts that could be combined to do the job but I have not actually done
this type of measurement (yet).

https://www.satellites.co.uk/forums/attachments/arduino_stepper-jpg.72933/
...shows a component to get the angular resolution and precision needed.
Manual operation gives 0,01 degree but microstepping the motor gives 4,5 arcsec
in 1/8-step mode when driving it electrically. The other part needed is the
absolute reference to what zero degrees is. Spirit-levels used in surveyors equipment
can be found with different resolutions, I think I've got one that is quite sensitive
with a millimeter resolution over tens of meters in range. Spirit levels can be adjusted
(zeroed) accurately without other tools than lots of patience.

A stable metal profile with a rotational stage with a spirit level on the moving part
would do the job. (The rotational stage in the picture is a Standa 8MR180 http://www.standa.lt)
A simple but accurate zero reference plus complicated mechanics in principle.

Electrical sensors with 0,01 degrees of resolution are horribly expensive but they do exist.

edit - sprellink erors
 
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I find this all interesting and some of it hard to digest, but what is the point in it all please ?, are we saying the likes of channel master have got all there measurements wrong and fitted the dish arms in the wrong place etc etc ?, what can we gain by all this please.
 
martin-f said:
I find this all interesting and some of it hard to digest, but what is the point in it all please ?, are we saying the likes of channel master have got all there measurements wrong and fitted the dish arms in the wrong place etc etc ?, what can we gain by all this please.
Click to expand...

Re. my cynical reply post 4,

Regards
 
The merest breath of wind and the precision is lost .........................
 
If we have possibility to precisely measure vertical angles than it ease precess of pointing antenna to satellite. It also can help to check whether LNB's phase center is located in antenna's focus (need to think sometimes before become cynical :mad: to not show your.... will stop here to not offend anyone). Precise measurement of vertical angles can help to tune polar-mounts. Such a tool is easy to make, so, no need to buy expencive protractors. Yes, will work when there is no wind, no rain.
This tool could be more helpful on big antennas, starting from Channel Master 120 and up.
 
But how does one engender sufficient rigidity that the precision is not lost in the merest breath of wind?
 
Tivù said:
But how does one engender sufficient rigidity that the precision is not lost in the merest breath of wind?
Click to expand...
That was just an idea , so I was asking, not saying that I am making such a tool :
RimaNTSS said:
Do some of you have experience making such a tool?
Click to expand...
:)
I think, it is possible to experience weather conditions when it is no wind at all, so tool could work.
 
I chase the weakest of signals all the time, and I have to position the lnb in a certain place from one satellite to another to get that weak TP, so imho/experience there is no correct place for me to point an lnb when messing with the faintest signals.
 
Can you elaborate about this statement more in detail martin-f?
What exactly do you adjust about the lnb position (skew, distance, look angle)?
Examples on what TP/sat you have to do this for?
 
This tool would also help to precisely measure your antenna's depth.
 
hvdh said:
Can you elaborate about this statement more in detail martin-f?
What exactly do you adjust about the lnb position (skew, distance)?
Examples on what TP/sat you have to do this for?
Click to expand...

No skew just backwards and forwards in the holder, I would have to check the transponders but I got a signal on a 60E TP with the lnb fully forward, I then kept trying for one at 17E and was unable to get any movement I moved the lnd fully backward and got a sniff of a signal,

If you check the 17E and 60E threads you will find the tp.
 
Yep trial and error for us mere mortals to get signal on TP we desire if b*ggering up other uninteresting TPs on the same sat. location, especially fringe reception areas.
eg. have daytime reception of uk psb channels up too SQ 82% on astra 2E BBC etc, but drop out when sat. does daily wobble, but no reception of channels on astra 2F, on gibby 125.
Saving up too buy a bigger dish but ATM other priorities.

Regards

Use free streaming in the evenings to open the channels of interest;)
 
martin-f said:
No skew just backwards and forwards in the holder, I would have to check the transponders but I got a signal on a 60E TP with the lnb fully forward, I then kept trying for one at 17E and was unable to get any movement I moved the lnd fully backward and got a sniff of a signal,
Click to expand...
Yes that's what I thought, 17°E is a good example of a satellite that not only needs sufficient gain, but also really needs the nulls besides the main lobe at the right place (19.2°E in this case). Probably at the expense of some gain, moving the LNB will accomplish that.

I remember while there still was Express-AM1 at 40°E, it was impossible to receive it with a 100 cm dish because of the strong nearby 39° and 42° transponders, but with some PVC pieces in front of the LNB these transponders miraculously could be received! For other satellites, these PVC pieces only made reception worse by a few dB.
 
Satellites.co.uk - the place where ideas come to die!

[martin-f] "are we saying the likes of channel master have got all there measurements wrong
and fitted the dish arms in the wrong place etc etc ?"
Where in the first posting is this mentioned?

[martin-f] "what can we gain by all this please."
So you can't ask anything here without it being beneficial to everyone?
A general way to measure vertical angles accurately isn't enough on its own?

[Tivù] "The merest breath of wind and the precision is lost"
Did he ask for a strom-proof solution?

[martin-f] "I can see the point of doing it on the cheapest dishes you could buy, but to think the
likes of channel master have got it wrong I find ludicrous to be honest."
Really? Where are channel masters etc. mentioned in the first question?
Most accurate measurement to 0,01 degree on the cheapest dishes, that is truly ludicrous!

Got an idea that's not "middle of the road" ? - Send it in - We quickly smother it so you don't have
to waste your and our time on things that we have no use for ourselves! The sarcasms are free!
 
Waveguide said:
Got an idea that's not "middle of the road" ? - Send it in - We quickly smother it so you don't have
to waste your and our time on things that we have no use for ourselves! The sarcasms are free!
Click to expand...

They was no sarcasms from me I just wondered what you was trying to achieve, now I realise your trying to make channel master and others look like fools, carry on its only your own time your wasting, but if it keeps you happy its all good :).
 
Discussion is the very essence of Forums, so Members are always free to augment/question/refute things, albeit in a friendly and respectful way.
 
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