My dishes collection

[AtOM13]

I think that Laminas dish doesn't have same problem like Channel master about Lnb position and G point, I think thzt Laminas original lnb holder position is almost perfect but not 100% sure at the moment ...
I made some tests again today and here are the best results:





Fibo setup is better, but need a C120 LNB which equal Megasat Diavolo LNB.
In original setup, black ultra old model 15.05 db Diavolo 15.23 db

 

[AtOM13]

Till I find a better C120 flange Lnb for a Fibo mount, this setup will remplace the Channel master in the trees :



After many hours of testing on 4.8e, here are my conclusions comparing to original setup:

- inox feedarms : + 0.1 db
- inox feedarms + scalar ring : + 0.3 db
- Fibo setup ( Black ultra lnb ): + 0.2 db
- Megasat Diavolo LNB (v1) still the best
( + 0.3 db compare to old IBU )

Better results when LNB is pointing center of dish:



All tests made "on the floor" so results will be normally better once installed in the tree.

Now need some times and calm weather to switch dishes

 

[a33]

Better results when LNB is pointing center of dish:

Good, interesting!

From what I learned from a specialist, aiming at the deepest point would be optimal (for "Gaussian" feeds).
I assume aiming to the deepest point is the best compromise between getting higher signal density, and having higher spillover loss; as compared to what you would get by aiming at the G-spot (at the end of the bisector line).

Deepest point is very near to the center of the dish.
See this picture: https://www.sat4all.com/forums/applications/core/interface/file/attachment.php?id=325336

Greetz,
A33

 

[AtOM13]

I just switched dishes,
Laminas is in place, up in the trees
Harder to put in place ... a real difference compare to Channel master!






Now I have to adjust declination, because dishes haven't same offset ( 22.6 for CM 20.1 for Laminas)
Declination was perfect with the Channel Master, do I have to adjust the bottom screw on this picture ? The screw on top is at maximum...

 

[ozumo]

The bolt in the blue circle adjusts declination, elevation (red circle) should stay the same as with the Channel Master dish. It may be possible to add washers between the plate and the dish to get the dish close enough to where the declination adjuster can be used to fine tune.

 

[AtOM13]

@ozumo Ok thanks!
Laminas need approximately 5° more in elevation compared to Channel master when installed directly on the polar mount...
So I just have to put washers between plate and the 2 lowers screw to elevate the dish ?

 

[ozumo]

The washers should go between the dish and the plate, or between the plate and the CM mount, not between the plate and the nut. Adding them to the two lower fixings will raise the dish.

If the offset difference between CM and Laminas is 2.5° then it should only need 2.5° less declination (more leaned back) to compensate, I think.

 

[AtOM13]

So I removed washers from the two upper fixings, and put it on the two lower fixings ( + 2 cms ) ...
No time to tune it again but now Laminas got same inclination as Channel master.

 

[AtOM13]

Ok, settings to 4.8e almost perfect, all sats on the arc are lockable like before (except 66e, need to cut some branches)
Now need fine tuning on 4.8e, then switch originals feedarms to inox feedarms with scalar ring and pray for locking all bein frequencies on 8w and 25.8e

 

[AtOM13]

Inox feedarms by Mister Rimants ok !
Very sensible to fine tune !
and scalar ring next...

 

[AtOM13]

Final mount with scalar ring.
Es'hail 2 MENA beam still unlocked here (expect 10730H at 6.4db during night)
10810H and others Bein sport frequencies reach 5.6 db maximum during night so 1db missing to lock.

I Will try a fine tune on 8w Bein frequencies next time ...

 

[EnoSat]

Final mount with scalar ring.

The blue scalar ring is optimized for the C band on offset dish. The Ku LNB already has its own ring for the Ku band under the red cover.

 

[AtOM13]

Yes I know, but adding it gives 0.3 db more

 

[EnoSat]

This means that the radiator/ring used in the Ku LNB is not designed for the given antenna (most are optimized for small dishes)

 

[Satfaca]

See this one, it always helps.

 

[Trust]

Final mount with scalar ring.
Es'hail 2 MENA beam still unlocked here (expect 10730H at 6.4db during night)
10810H and others Bein sport frequencies reach 5.6 db maximum during night so 1db missing to lock.

I Will try a fine tune on 8w Bein frequencies next time ...

View attachment 163027

Sorry but I have to say : buy a new dish , never seen so much dents , a greater scalar wont help much .

 

[John]

Sorry but I have to say : buy a new dish , never seen so much dents , a greater scalar wont help much .

I have to agree, i prepared an explanation slide earlier intending to post to forum but couldn't bring myself to do it.
My concerns was also what looks like the physical surface damage to the dish face, assuming it is the same on the front side and also the use of the Cband scalar. With the correct positioning and type of the lnb that has the right / correct matching characteristics to correctly and accurately illuminate the dish face you should be able to get the same dB readings or better without the use of the Cband scalar. Also , and this is really nit-picking , the top half of the Cband scalar is having a very very slight signal masking - only of some concern if you are a low level signal Dx chaser like myself - 99% of the time it will be irrelevant and the system will work - but not to it's full potential. Good luck with the project though.

.........................................................................................................................................................................................................................................................................................................

 

[AtOM13]

Yes I agree, there's lot of dents but only on the back side part, reflector side is perfect, its not the same constrution as a channel master ( not the same quality too)
Only a bigger dish will give better results, 2 db more on MENA beams are logical.

 

[a33]

Also , and this is really nit-picking , the top half of the Cband scalar is having a very very slight signal masking

Indeed, 'clearance distance' seems to be "just" 49 mm for this dish, I just calculated.

But still, the dish is 1610 x 1512 mm...... plenty of surface to counteract this slight signal masking, in my vision.

Greetz,
A33

 

[AtOM13]

Indeed, 'clearance distance' seems to be "just" 49 mm for this dish, I just calculated.

What is "clearance distance" ?
Not easy to see on pictures but dish is only hidden with "low" branches, none of them block signal (Ok from 66e to 40w then house block signal )