₦airaland Forum

geometry:
@ Newtonn,

to determine an equivalent half the diameter of scalar ring, you measure from the center of the hole on one of the three arms to hold the tripods, to the center of the ring for the lnb. the value should be somehow close to 8.25cm. try it .

geometry:
@ Newtonn, Newtonn, Newtonn.

i have called you three times now !
oya, take your tape and try to measure the diameter of a c-band scalar ring and tell me what value you get. since your calculation is based on the half of it , you divide what you get as diameter by two.
i am repeating this again, 'when i used my vernier calipers i got the diameter of c-band scalar ring to be 16.5cm.'
dividing this figure by two , what do you have ?
in my own case i got half of 16.5cm to be 8.25cm. let us know what you have.
now go to illustrated diagram again, stick with the 'actual', and that is what makes the difference.
i am very sure by now you are laughing.!!!
lol.
JUST TAKE YOUR TIME TO WORK ON THE 'ACTUAL' DIAGRAM, HAVE A CRITICAL LOOK AT IT AND YOU WILL SEE WHAT AND HOW DODOS HAS OVER COME THIS SAME PROBLEM.
CHEERS.
BY THE WAY, YOUR CALCULATION SEQUENCE LOOKS VERY GOOD, JUST BEAT THAT OBSTACLE, NOW!

remember pythagoras theorem ?
consider the two diagrams ; i.e theory and actual. stick to the theory. it gives you the actual tripod length with just little adjustment to actual focal length of your parabola [dish:
.
pytagoras states that; the square of the longest side (h^2 ) of a triangle is equal to the sum of the squares of the rest two sides
( a^2 + b^2 ) . i.e h^ = a^2 + b^2
in the case of the represented diagram ,

h = t,
a = line CB,
c = line AB
FOR CLARITY SAKE, in the actual diagram, there is a value for s , which is the radius of the scalar ring. the same value goes for ku- band lnb holder as indicated in the diagram.
by using my vernier calipers i got scalar ring diameter to be 16.5cm i.e the radius comes to 8.25cm which is (s)
hence; (a) = line CB = radius of the dish - s . i.e [DIAMETER/2] - 8.25CM.
(C) = line AB = focal length - x. i.e f - DEPTH, = f - x,

don't forget x represents how deep your dish is.

Newtonn, do you see why u need to measure your dish depth ?

@geometry,
my question how do you come about 8.25cm for scalar ring?
is 8.25cm the standard size for all scalar rings?
ralph

dodos:
@ all

I am trying to figure everything out myself now.  Anyway am not convinced of the above figure for the tripod.  If it is pythagoras you used and did not approximate any value leading to your answer then i think the value for the tripod is wrong.  Can you prove me wrong.  My calculations which i have rechecked says it should be 175.0863 which i have now approximated to 175.1cm.

Can u prove otherwise.

My parameters were

Focal length : 123.1 cm
Radius         : 160 cm

Now remember his depth was 52 cm so take that out of the 123.1 : (123.1 - 52) cm = 71.1 cm

Now using pythagoras: (71.1) squared + (160) squared = (the length of the tripod) squared

Now the length of the tripod = square root of {(71.1) squared + (160) squared}

                                             = 175.0863 cm
approximately                        = 175.1 cm

Thanks

dodos:
@ all

I am trying to figure everything out myself now. Anyway am not convinced of the above figure for the tripod. If it is pythagoras you used and did not approximate any value leading to your answer then i think the value for the tripod is wrong. Can you prove me wrong. My calculations which i have rechecked says it should be 175.0863 which i have now approximated to 175.1cm.

Can u prove otherwise.

My parameters were

Focal length : 123.1 cm
Radius : 160 cm

Now remember his depth was 52 cm so take that out of the 123.1 : (123.1 - 52) cm = 71.1 cm

Now using pythagoras: (71.1) squared + (160) squared = (the length of the tripod) squared

Now the length of the tripod = square root of {(71.1) squared + (160) squared}

= 175.0863 cm
approximately = 175.1 cm

Thanks

geometry:
@ swordswifter,
i guess your dish is kinnda' too flat for acceptability. the acceptable range i know for f/D ratio range is 0.3 through 0.7 , for [TVRO] (Television Receive Only), yours might be a kind of push to the edge and i hope it works for you.
i 'l like to see your result for comparison, and maybe what you have supersedes the previous records. it could be a land mark, but then i'm afraid.
let's hope yours is a landmark success.
plz, feel free to let us have your results.
thank you.

swordswifter:
Hi all,
I'm announcing that The home made dish making adventure i embarked on which i nicknamed THE PROJECT with the help of a couple of friends since last year is now finally complete.Preliminary testing showed strong echoes arriving at the focal point.Actual testing will start tomorrow 8am local time at the Ghana Telecom University College campus-Tesano and as usual pictures will be posted afterwards.Dodos,Sathob,Salamander and other active nairalanders living in Accra are free to come and support.Thanks!
FTA-We will push the limits.

swordswifter:
Hi all,
I'm announcing that The home made dish making adventure i embarked on which i nicknamed THE PROJECT with the help of a couple of friends since last year is now finally complete.Preliminary testing showed strong echoes arriving at the focal point.Actual testing will start tomorrow 8am local time at the Ghana Telecom University College campus-Tesano and as usual pictures will be posted afterwards.Dodos,Sathob,Salamander and other active nairalanders living in Accra are free to come and support.Thanks!
FTA-We will push the limits.

swordswifter:
@Geometry
It's 244cm in diameter but i know with time due to expansion and cooling it will reach 250cm.
If all things are to go as planned these are the parameters we are expecting:
Frequency 11296 MHz
Diameter 2440 mm.
Depth 150.00 mm.
f/D 1.01666666666667
-------------------------
f/D = 1.02
Focal Length = 2480.67 mm.
Illumination angle for feed = 55.3 degrees
Space attenuation = 0.51 dB
Desired taper = 9.49 db for 10 dB edge illumination
A simple feed horn would have a diameter of 2.12 wavelengths for a 3 dB beamwidth of 31.07 degrees
Gain at 50% efficiency = 46.20 dBi

swordswifter:
Hi all,
I'm announcing that The home made dish making adventure i embarked on which i nicknamed THE PROJECT with the help of a couple of friends since last year is now finally complete.Preliminary testing showed strong echoes arriving at the focal point.Actual testing will start tomorrow 8am local time at the Ghana Telecom University College campus-Tesano and as usual pictures will be posted afterwards.Dodos,Sathob,Salamander and other active nairalanders living in Accra are free to come and support.Thanks!
FTA-We will push the limits.

swordswifter:
Hi all,
I'm announcing that The home made dish making adventure i embarked on which i nicknamed THE PROJECT with the help of a couple of friends since last year is now finally complete.Preliminary testing showed strong echoes arriving at the focal point.Actual testing will start tomorrow 8am local time at the Ghana Telecom University College campus-Tesano and as usual pictures will be posted afterwards.Dodos,Sathob,Salamander and other active nairalanders living in Accra are free to come and support.Thanks!
FTA-We will push the limits.

geometry:
@ newtoon,

remember pythagoras theorem ?
consider the two diagrams ; i.e theory and actual. stick to the theory. it gives you the actual tripod length with just little adjustment to actual focal length of your parabola [dish].
pytagoras states that; the square of the longest side (h^2 ) of a triangle is equal to the sum of the squares of the rest two sides
( a^2 + b^2 ) . i.e h^ = a^2 + b^2
in the case of the represented diagram ,

h = t,
a = line CB,
c = line AB
FOR CLARITY SAKE, in the actual diagram, there is a value for s , which is the radius of the scalar ring. the same value goes for ku- band lnb holder as indicated in the diagram.
by using my vernier calipers i got scalar ring diameter to be 16.5cm i.e the radius comes to 8.25cm which is (s)
hence; (a) = line CB = radius of the dish - s . i.e [DIAMETER/2] - 8.25CM.
(C) = line AB = focal length - x. i.e f - DEPTH, = f - x,

don't forget x represents how deep your dish is.

Newtonn, do you see why u need to measure your dish depth ?

dodos:
@ geometry and sword

Can you please explain how you came by the above. Secondly are all c-band lnb holders the same size.

Thanks for your patience

dodos:
@ geometry and sword

Can you please explain how you came by the above.  Secondly are all c-band lnb holders the same size.

Thanks for your patience

bolyjay:
@newton,you can white glossy paint and for the foil you can get it at any super market or at any stores that sell baking items.hope this info.helps.

arsenal1:
@ Newtonn I receive abudhabi sport hd with 2.4m pan on badr4/6 in owerri

arsenal1:
@ Newtonn I receive abudhabi sport hd with 2.4m pan on badr4/6 in owerri

George_D:
pictures of my 3m fibre refoiling job over the weekend.

geometry:
@ lovala,,
you are right !
@ newtonn,
you wrote 160cm then bracketed 1.8m. But then, since you said your dish diameter is 320cm right from time, i assumed your your bracketed 1.8m is meant to be 1.6m. Plz, comfirm it.

dodos:
@ geometry

good work and good illustrations. I enjoyed recollecting my elementary math. Now concerning the depth of the dish, how can you measure in order to avoid errors. In other words one would have to measure from the center (in the middle) of the base of the dish to edge of the dish.

Am thinking of using a thing thread from one end of the tip of the dish to the other (as if measuring the diameter) and then putting a stick in the base of the dish up to the thread. Is this how to go about it. If yes how can one ensure that the stick is in the exact middle of the dish. What else can one do to eliminate or minimize errors as much as possible.

Hope my question is self explanatory

Thanks

geometry:
@ newtoon,
remember pythagoras theorem ?
consider the two diagrams ; i.e theory and actual. stick to the theory. it gives you the actual tripod length with just little adjustment to actual focal length of your parabola [dish].
pytagoras states that; the square of the longest side (h^2 )  of a triangle is equal to the sum of the squares of the rest two sides 
( a^2 + b^2 ) . i.e h^ = a^2 + b^2
in the case of the represented diagram ,

h = t,
a = line CB,
c = line AB
FOR CLARITY SAKE, in the actual diagram, there is a value for  s , which is the radius of the scalar ring. the same value goes for ku- band lnb holder as indicated in the diagram.
by using my vernier calipers i got scalar ring diameter to be 16.5cm i.e the radius comes to 8.25cm which is (s)
hence; (a) = line CB = radius of the dish - s . i.e [DIAMETER/2] - 8.25CM.
            (C) = line AB = focal length - x.           i.e f -  DEPTH, = f - x,

don't forget x represents how deep your dish is.

Newtonn, do you see why u need to measure your dish depth ?

williams85:
can some one confirm if ait is still on intelsat901 @18west

kinmen2004:
@newton it depends on your location

timosat:
@swordswifter,pls can u help me out:do u have any working cline on w3a. I'm on a project I need your help my email is edeki4real@gmail.com just forward me valuable info. I need to discuss with u.Thanks.