₦airaland Forum

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Sorry for the delay, a lot us in this section of Nairaland understand why the pictures posting has to take this long, first of all , I will like to thank those that have kept the section interesting, those that latter joined and make enormous contributions like spurring me and those that are just interested in where this is going to end, we must all know that this is not the end of this section, but rather the beginning,, I am able to learn a lot from trying to give out token. This is how it should be. I waited long to see who will brave the process and come with a total different ideas from what i have, I am able to see the potential in Africa and I am able to reaffirm my confidence in all of us. We are a great people with wisdom and there lie so many things that are worth trying. Remember, when we try and ''fail'' it not really a failure, rather we have learnt a new way of doing the same thing but in a wrong way. My brother in the Ghana axis, more grease to your elbow. You are great ! Your work is a good platform for others that might want to follow the same path to thread.
Once again, thank you all. We should wait for another exiting experiment.

Hint:
We continue asking question in the same section on what to do to get a mould made. Remember we have just started!!!

@williams,
the best paint for satellite antenna is light grey, ''ash''

@larryenob

No gum works good, except using fiber glass material itself,, i.e, resin, catalyst and accelerator. these are common market names for these materials and there is a sequence and proportions at which they are combined, find out how to use them before start. it is a WARNING !

@newtonn,
you forgot to tell the house how the tripod configuration given to you worked , the house needs to know so that one or two people could have a grab of something too.

@swordswifter.
That was close. but then, consistent bending of the ribs is an act of mould making at every point of it. if you are making a dish without building a mould means every time you have to litterarily go through partial mould building.

I am presently not in the country, my number won't go, but i got your message in my email box which I replied promptly. check your mail.

This house has been On holiday for almost a week or so now, let us see what we can do with metallic satellite dish fabrication, using square pipes and steel sheets , this material is known to factually everybody, no actual mould construction needed. ANYDODY ?

@ultrasat,

that is me really, nice having you on board. but right now, i am not in town. i mean i reside outside the country. how is life in osogbo generally?
well, we could exchange chat on yahoo. plz,let me know your email. thank u for the gesture. hoping to chatting u soon.

@ultrasat

why don't u let me know who u are at once and stop playing a kindmind game on me. obviously, this is somebody that knows me very well,,
before i give in LEKAN WHAT ?

@ultrasat,
give me the dossier of the geometry you know then i will confirm it.
are u A LADOKITE ?

@swordswifter

definitely sword, definitely, sure,
its like that but then you started well.
that i can assure you.

from my analysis of your tripod combination with the threaded bolt, it should work fine, to achieve the 167 real tripod length, adjust ,through the threading down below the welding zone say, a distance of 8cm. i.e your tripod pipe length+ a value on the threading that makes it = 167cm
you can just work this out. say, pipe + adjusted thread = 167cm
i hope i make any sense.
as for your east-west rod, that is secondary , it is strongly the unction of your neck and your actuator holder on your dish.
i hope your u-mount [neck] is firm and the holes drilled on them are to precision.

@newtonn,
your lnb selection seems the best. u can just go a head.

@newtonn,
sorry for the late response,
ensure the value calculated for the tripod be the measurement of the pipe part, even before bending.

@newtonn,

pls increase ur hole depth to 1.5ft to 2ft.
do proper cement casting , concrete

@newtonn,

sorry, i can not respond now, give me time.

@ swordswifter,

f/D ratio is quite important in the designing of a satellite antenna, [dish].; it describes how deep or shallow your your dish is. there are values attach to different purposes for which an antenna is meant. it is the factor that describe the illumination method adopted in the antenna service life. there are different illumination methods for various reasons. i.e to guide against the interference from the ground [ground noise] or ground temperature.
i.e a too flat a dish would accept more ground noise than a deeper dish, while a dish that is too deep would not allow full illumination,,,and that is why we cut lnb especially for Out of-Foot- Print-Signals. because we are looking for a situation to fully bring larger percent of the converged signal to the lnb throat, apart from exposing the probes,.,,,here we are literally explaining 'beam angle'. some would call it apex angle and the rests. but then, the simplest way to understand this is to imaging your lnb to be a torch light placed at the focal point, facing downward, the light from it now is expect to throw light upon the surface of the dish, remember your focal length is fixed, hence, the position of the torch is fixed, adjust the beam so as to cover the entire surface of the dish. this is the lay-man explanation of antenna ILLUMINATION, in visualization, one could reason it out that the further away the torch the easier it is to get the surface illuminated by the torch, and the more difficult it is for a touch too close to the surface to illuminate the dish surface.
From research results, it has being established that there is a critical value of f/D ratio for critical antenna illumination, ,,,and the value is 0.41 . I HAVE EXPERIMENTED THIS VALUE ,AND FOR REASONS, ADOPTED VALEUS LITTLE BIT BELOW AND ABOVE IT WITH VERY VERY GOOD RESULTS. i.e 0.39, 0.4, 0.42 and the extreem i have gone was 0.45. though i experimented 0.6 f/D before but not for TVRO, satellite tv.
i advice anybody in the house to choose 0.4 f/D ratio ,it worked for me.

that is a measurement on the locally made lnb holder.,,,though there are errors associated with locally made lnb holder are numerous. 1] imperfect lnb position ring. 2] imperfect spacing of the holder arms on the ring. 3] non planar array of the holder arms. and on and on and on.,,,,,,

@ 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 .

@ 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!

@ Dodos

swordswifter's tripod length is within the neighborhood of 259.28 cm

@ newtonn.

tripod squared = (focal length - depth) squared + (dish radius - scalar ring radius)squared,,,

@ dodos,

you all have not taken to my warning about not going by the THEORY, i mean the diagram that i referred to as theory. I STATED that we should stick to the ACTUAL, the diagram referred to as actual. compare the two diagrams and you will see the reason you not arriving at my answer.
Even when i made a mistake of saying 'stick with the theory' which i latter corrected almost immediately , that we should go by 'actual'.
the values you have arrived at are from THEORY.
THE DIFFERENCE;
SIMPLY DEDUCT THE VALUE OF SCALAR RING FROM YOUR RADIUS BEFORE SQUARING IN YOUR PYTHAGORAS FORMULA.
LETS GO!

@ swordswifter,
you care for a chat ?. I will be happy to talk to you. Personally.
Thank you.

@ newtonn,
your observation is accurate, that's the essence of designing, simulating and re-designing. All of these are important in science &engineering. (theory).
The linear diameter is what i call 'PARABOLIC ARC'. : You can say your curve length. You can verify this by real curve fittings on a piece of paper adopting an adequate scale. Then, use graduated french curve to measure out the curve and multiply by your scale. Compare your result with that from the software. They must be the same or with a neglegible variation.

@ swordswifter,
from your parameters and properties, your dish seems to be made of metal, i believe that answer the reason for the magnitude of your f/D ratio, 1.02.[ very high] 'fabrication convenience' !. then, if i may ask, how many sections, if you are working on a metal dish.
plz, let me know, it might help.
goodluck !