Advice Needed Famaval dish tweaks

A

Alejandro_V

Member
Messages
20
My Satellite Setup
Maximum E-85, 3 lnb's, 5w, hb13, Astra 19.2
My Location
Norway
Admin edit - posts moved off Astra 2E discussion thread as this deserves its own topic. Previous thread is here


A/S



As you have realized, one needs a sliding\adjustable system to properly being able to control the lnb pointing at best dish hotspot.

Now, in my case(s) this made the dish(es) immensely better for the weakest uk spot beams, may or may not apply to your setup, just providing some tips that may be of help in getting the most out of the dish.

As a test, after doing the best possible adjustments with everything stock, loosen the bottom bolt and gently slide the arm a little while watching the meter closely. On my Famavals the levels jumped up immediately, and the dish went from meeeehhh to very decent for the price. Now secure the arm at the best levels, recheck the dish by gently pushing the edges and see if levels go up or down, evnt. readjust for best levels, go back to the bottom arm, get best levels, repeat etc until nothing gets better :O)

Picture, the temporary-eternal adjustment test-system on my 120 in Norway. Never make temporary experiments that actually works, it'll stay that way :O)
Old thread but hopefully you will get this message, I do also have a famaval 120 (x110) and I'm struggling here in Oslo after eutelsat e5wa was replaced by E5WB... I would like to try this tip but I do not recognise the bottom bolt, in my dish the whole arm is hold by two bolts against the dish in addition to two sticks...but I believe the lnb holder is clicked in the arm so maybe I could try to adjust that one?
 
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4wd

4wd

Getting the picture
Messages
1,574
My Satellite Setup
5 W, 9-13-19-28 E
My Location
Bergen, Norway \ Alpes Maritimes, France
Hi, my 2 famavals got 1 bolt fixing the arm at the dish bottom.
If different, a picture of your bottom arm fixation would clarify.

The 'slider' (the temporary tests from long ago still in use :O) is in practice shortening the bottom arm, thus the lnb aims very slightly higher + very sightly changed angle towards dish, gained several crucial db's.

The mod saved me quite some money, the inexpensive famavals became (just) good enough for 28e UK both in Norway and France. And both got 19e lnb added using 'les moyens du bord', working fine.

Of curiosity, 5w, aiming for the multi's ?

Edit, added closeup picture, looks horrible, but concept was good and has been 100% stable :O)
 

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A

Alejandro_V

Member
Messages
20
My Satellite Setup
Maximum E-85, 3 lnb's, 5w, hb13, Astra 19.2
My Location
Norway
Hi, my 2 famavals got 1 bolt fixing the arm at the dish bottom.
If different, a picture of your bottom arm fixation would clarify.

The 'slider' (the temporary tests from long ago still in use :O) is in practice shortening the bottom arm, thus the lnb aims very slightly higher + very sightly changed angle towards dish, gained several crucial db's.

The mod saved me quite some money, the inexpensive famavals became (just) good enough for 28e UK both in Norway and France. And both got 19e lnb added using 'les moyens du bord', working fine.

Of curiosity, 5w, aiming for the multi's ?

Edit, added closeup picture, looks horrible, but concept was good and has been 100% stable :O)
Hi and thanks for the reply! Attached a picture from the manufacturer showing the arm and the reinforcers, tomorrow with daylight I will make some of my installation. Right now I have marginal signal, between 9 and 10 dB depending on the transponders. I'm waiting for an inverto LNB and I also need to check my cable to see how much I can gain. Most probably I will not avoid going for a 125 or maybe 150 but I would really like to avoid it. So if your mod gives me the few dB's missing I can save a lot of work and money :-) I use e5w mainly for getting access to French sport channels, I basically pay 1 fourth of what I would pay for a regular Norwegian subscription! Everything was awesome with E5WA but since they changed to B one week ago it's a nightmare! Thanks a lot again :-)
 

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4wd

4wd

Getting the picture
Messages
1,574
My Satellite Setup
5 W, 9-13-19-28 E
My Location
Bergen, Norway \ Alpes Maritimes, France
Hi, my tweak only applies to this range > 130 TRX - FIXA | Products | Famaval

But if you find a way of experimenting on your dish, maybe try something to see if there is some better lnb hotspot available.
 
A

a33

Specialised Contributor
Messages
598
My Satellite Setup
XSAT410
Rebox RE-9000
My Location
NL
As was in the earlier thread:
You can do some measurements on the dish, and calculate parabolic focal point position.
That would be an excellent start for experimenting?

Greetz,
A33
 
RimaNTSS

RimaNTSS

Super Moderator
Staff member
Messages
4,975
My Satellite Setup
Some SAT-related hardware.
My Location
N-E from Riga
I think that Famaval is cheating..... they want to sell their products better, for that they call their dishes in the special way :confused. For example. product "130 TRX - FIXA" is only 122cm dish, product "125 TRX-FIXA" is only 117cm dish and so on. In addition they do not mention such a important parameter of the satellite antenna as it's offset angle. I agree with A33, proper way to go ahead is to check geometry of the reflector, measure it precisely, calculate position of the focal point, offset angle and aiming point on the surface of the dish. Then check whether original LNB-holder really holds LNB in the right position, if not - adjust it. Simple as it :)
 
A

Alejandro_V

Member
Messages
20
My Satellite Setup
Maximum E-85, 3 lnb's, 5w, hb13, Astra 19.2
My Location
Norway
First, thanks to the admin for creating this thread! Then, regarding size of dishes, I think that what you're saying @RimaNTSS , is valid for most (if not all!) manufacturers, for example, Gibertini 125 has a 121x130 dish...anyway, I will make the measures you are suggesting later, since now it's a little bit cold outside :-) I tried the trick of moving the arm though (4 screws to the dish + 1 extra on the side sticks) but I did not get any significant improvement. As said, it's a little bit cold, so I was rather quick, I will give it a try later when I have made the measures and will let you know. I'm waiting for a new LNB, hopefully today, as far as I've understood, this can also give a significant effect!
 
Channel Hopper

Channel Hopper

Suffering fools, so you don't have to.
Staff member
Messages
29,121
My Satellite Setup
A little less analogue, and a lot more crap.
My Location
UK
Don't forget the local councils (in the UK) count the total height/widths in order to screw people over when it comes to planning requirement, though the manufacturer might only give the dimension of the effective reflector surface, ignorng the reinforcment 'lip' around it.

With any dish the most important factor is the gain, and the better marques will provide repeatable figures at the three points on the Ku band, low/medium and high.
 
A

Alejandro_V

Member
Messages
20
My Satellite Setup
Maximum E-85, 3 lnb's, 5w, hb13, Astra 19.2
My Location
Norway
As was in the earlier thread:
You can do some measurements on the dish, and calculate parabolic focal point position.
That would be an excellent start for experimenting?

Greetz,
A33
Hi there! I made some measures (H=114, W=106, D=8), I found some formula which should then give the focal distance = w.w.w/(16.H.D), is that what you are using?
 
A

a33

Specialised Contributor
Messages
598
My Satellite Setup
XSAT410
Rebox RE-9000
My Location
NL
That would be John Legon's equation for a parabolic dish.
It uses the depth at the deepest point of the parabola, and gives focal length of the mother prime focus antenna, that is the distance from focus to vertex (center of the PF dish).
When you don't know where the vertex lies, just this formula doesn't bring you much further; you need other calculations as well....



A very good program is Parabola6 by Strannik, using inputs width, height, and depth at the center of the dish.
Downloadable in the first post of this thread: Юстировка офсетных антенн. Программа и примеры настройки - Sat-DX.сlub

As the program is in russian or a similar language, an short explanation by RimaNTSS is here:
Antenna's focal point - "le point G" - SatsUK



I also developed a spreadsheet calculator for parabolic dishes, having several input possibilities (including the Parabola6 method, that is also my absolute favorite method for flat-dishface dishes).
I can calculate for you, if you wish (the calculator is not on the internet yet).
Example of outcome:

A33 Triax TD115 new measurement Oct2019.png

And indication of the points, mentioned in the calculator:

A33 sat dish calculator 3 .png


Beware: Some other calculators on the internet are not without faults! The offset part of Parabola calculator 2.0 has faults, and the topstring/bottomstring calculation of satsig.net is wrong.


BTW: For exact outcomes, a depth measurement better be more precise than just 8 (cm? inch?). Better 8.x, or even better 8.xx.


Greetz,
A33
 
A

Alejandro_V

Member
Messages
20
My Satellite Setup
Maximum E-85, 3 lnb's, 5w, hb13, Astra 19.2
My Location
Norway
That would be John Legon's equation for a parabolic dish.
It uses the depth at the deepest point of the parabola, and gives focal length of the mother prime focus antenna, that is the distance from focus to vertex (center of the PF dish).
When you don't know where the vertex lies, just this formula doesn't bring you much further; you need other calculations as well....



A very good program is Parabola6 by Strannik, using inputs width, height, and depth at the center of the dish.
Downloadable in the first post of this thread: Юстировка офсетных антенн. Программа и примеры настройки - Sat-DX.сlub

As the program is in russian or a similar language, an short explanation by RimaNTSS is here:
Antenna's focal point - "le point G" - SatsUK



I also developed a spreadsheet calculator for parabolic dishes, having several input possibilities (including the Parabola6 method, that is also my absolute favorite method for flat-dishface dishes).
I can calculate for you, if you wish (the calculator is not on the internet yet).
Example of outcome:

View attachment 128523

And indication of the points, mentioned in the calculator:

View attachment 128522


Beware: Some other calculators on the internet are not without faults! The offset part of Parabola calculator 2.0 has faults, and the topstring/bottomstring calculation of satsig.net is wrong.


BTW: For exact outcomes, a depth measurement better be more precise than just 8 (cm? inch?). Better 8.x, or even better 8.xx.


Greetz,
A33
Thanks! Yes m, it's 8 cm but I believe I need to take some more accurate measurements, I will let you know, it is still cold outside here
 
A

a33

Specialised Contributor
Messages
598
My Satellite Setup
XSAT410
Rebox RE-9000
My Location
NL
OK, take your time.
Remember it's about the working area of the dish, so without the rim.
Also take into account the hight of the rim, when measuring depth.
Height and width can be measured in mm, depth if possible even more accurate (half a mm makes a difference!).

Greetz,
A33
 
ac1139

ac1139

Member
Messages
25
My Satellite Setup
120 cm, working on 180 cm dish.
My Location
100 km north of Vienna
Off topic: For translating russian language web site into english one is possible to us google chrome browser. Just insert link and choose "translate" in the right top of chrome browser.
prekla.jpgpreklad.jpg
 
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