SMW OA 1600 dish

[Captain Jack]

And some terrible accident happened. Unfortunately magnet does not work here
View attachment 80765

I bet it won't rust though.

 

[RimaNTSS]

Not interesting at all... Set dish elevation 12* (25* satellite elevation - 13* offset angle), put LNB in calculated position, adjusted azimuth till get lock. It took small amount of time, not interesting
Unfortunately all signals from 23,5*E are too strong that I can not make estimation about performance of this dish.

 

[RimaNTSS]

Not bad at all.... 23,5*E in the middle and 9*E on the edge. And I already decided how to modify this dish. Everithing red-crossed will be removed and additional bar (circled blue) will be added.

 

[archive10]

And some terrible accident happened. Unfortunately magnet does not work here
View attachment 80765

I tried something similar once.
Althought for me, it involved a trolley suit-case, and leaving an airport security machine.
(you won't believe how far things can fly in an airport...)

 

[archive10]

Not bad at all.... 23,5*E in the middle and 9*E on the edge. And I already decided how to modify this dish. Everithing red-crossed will be removed and additional bar (circled blue) will be added.

I can see that you may indeed get ahead of me mounting the OA-1600.
I wont have time before next week to put mine up! (and if it rains too much, it wont be until August - holidays are here!

 

[RimaNTSS]

So, made new INOX holding bar which firstly will hold everything together and secondly will also hold new bar to hold all LNBs. What kind of LNB holders... do not know yet.

 

[archive10]

So, made new INOX holding bar which firstly will hold everything together and secondly will also hold new bar to hold all LNBs. What kind of LNB holders... do not know yet.
View attachment 80777 View attachment 80778

"...left the garage flooded from the sprinklers. It also left a man's decapitated body lying on the floor next to his own severed head. A head which at this time has no name..."
"I know his name..."
OA-1600!

 

[RimaNTSS]

Made a temporary LNB-bar holder. When I find proper position of the bar will polish everything. Hot sure whether LNB-bar should be curved as distance from LNBs to the dish can be changed by moving LNBs closer/further.

 

[Trust1]

Hello Rima , are that those BU's with adjustable focus ?

 

[RimaNTSS]

Wim! Not adjustable, but adjusted firmly. One is for 70* illumination and another one for 90* illumination. That is according to producer, but I can not confirm or deny this. One thing I like in those LNBs for sure- they 40mm all trough and easy to be installed/dismounted.

 

[RimaNTSS]

With the central 23,5*E I got 0,8*W on the end of new bar. Have not compared signal levels to other antennas but here is almost 15dB on 0,8*W. If it goes like this on other side of bar (pretty sure it will be more or less the same) than other edgy satellite will be something like 45*E. I like this dish!

 

[RimaNTSS]

Finished with frame. Do not really like those LNB holders, but what can be done better? Also washed BS from the face of the dish.

 

[RimaNTSS]

Originally antenna had 2 support struts . By now I do not feel need for them. But, it is quiet easy to make them (red).

 

[RimaNTSS]

Made some LNB holders. Unfortunately running out of clamps Also need thin M8 nuts just to reduce total weight of the construction.

 

[RimaNTSS]

So, that is multifeed for 10 LNBs. Still missing one pair of clamps, therefore it does not look perfect

 

[archive10]

Originally antenna had 2 support struts . By now I do not feel need for them. But, it is quiet easy to make them (red).

They where probably there for a reason.
Could be to handle extreme cases of loading.
It is likely that the SMW LNBs of old were quiet heavy items, meaning that 5-6 of those could weigh down the whole arm assembly to deteriorate the performance.
These days, economy LNBs with plastic feed-horns weighs very little, so you would need, say, 10 of those with metal clamps to make a noticable difference.
Wait - did I say 10??

 

[RimaNTSS]

Spent some time today working on this dish. Firstly moved it couple of meters West thinking that neighbor's house will not be on the way to birds, I was wrong.... it does not allow to get decent signal from 45*E and 42*E also partially obstructed. But on other satellites got good results. Unfortunately do not have free 1/10 Diseqc, so if I need to switch to another satellite I go out and reconnect F-connector. Will probably do tests satellites one by one. I also see that there is a potential to install 2 additional.... no, I will not do that.

 

[archive10]

Spent some time today working on this dish. Firstly moved it couple of meters West thinking that neighbor's house will not be on the way to birds, I was wrong.... it does not allow to get decent signal from 45*E and 42*E also partially obstructed. But on other satellites got good results. Unfortunately do not have free 1/10 Diseqc, so if I need to switch to another satellite I go out and reconnect F-connector. Will probably do tests satellites one by one. I also see that there is a potential to install 2 additional.... no, I will not do that.

Very nice, but what I don't understand is: All your LNBs seem to havin roughly the same alignment.
If the dish is toroidal, then surely they should fan out from east to west?
I mean, this is like your discussion about "le point G" of the offsets; only in the vertical direction...

So, the question is: "Where in the horizontal plane of the toroidal dish should the LNB be pointing???"

...or is the answer that it's not that important, as long as the wavefront is funneled into the LNB feed tube?

 

[RimaNTSS]

Good questions @st1 !

All your LNBs seem to havin roughly the same alignment.

Not really.... Central LNB is more down and forward in such a way that distance from each LNB's focal point has same distance to it's own "Le point G" on the surface of the dish. In Post #7 I was trying to show (green solid line) all points G connected. Perhaps I was wrong... but I can check that drawing real line on antenna by connecting all real points G. Secondly, edgy LNBs are higher than central LNB, that is because Clarke-belt is not straight but curved from antenna point of view.
I think this antenna would better work on the equator looking directly up and all satellites seen on one straight line.

 

[Archived-1]

That looks great Rimants , cracking job.