Best Lnb for 2.40 dish feeds low signal at Eutelsat 7 east ?

7mdish

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It does not seem an LNB issue. As just mentioned above, 0.3 or 0.1 is not so different, especially with a so large dish.
You must get very strong signal with 2.4m in Greece, not only on normal broadcasting transponders but also on feeds.
For example, what about the 3 main news feeds at 11043H,11050H,11056H, all SR 4937?
Obviously they are weaker than other frequencies, but what is your level in dB?
If you are not able to lock them, please check the dish pointing and the LNB focal point. Changing the LNB is time and money loosing in my opinion, other than any possible LNB fault.
 

Terryl

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If someone can post the right distance for the LNB holder on that size dish it may help him out.
 

hatters1976

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After discussing the issue with my technician here because this 2.40 has been installed 20years+ ago he was not sure
he mentioned that at that time there were in the local market famaval, mabo, dh, channel master etc ... so he was not sure 100%
I decided with my uncle to do again the painting this time colour white as i am afraid of the temperatures here in
the summer. Thank you all for your opinions. I will upload and image from the side of the dish tomorrow morning.
 

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Terryl

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A flat white epoxy based paint would be my best choice, it wound flak off after a few years.
 

a33

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The Famaval dish has the screw holes for the expansion modules at 3.10m on the edge, since these are no longer there it could be that the feed rods are still the ones for 3.10m !
So the F/D ratio doesn't match and the focal point doesn't match either, the LNB distance is then too far away from the dish !

With (or without) expansion plates, the focal distance would remain the same. Though the f/D ratio would indeed change.
So I don't understand what you write, here? Am I missing something?

Greetz,
A33
 

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After discussing the issue with my technician here because this 2.40 has been installed 20years+ ago he was not sure
he mentioned that at that time there were in the local market famaval, mabo, dh, channel master etc ... so he was not sure 100%
I decided with my uncle to do again the painting this time colour white as i am afraid of the temperatures here in
the summer. Thank you all for your opinions. I will upload and image from the side of the dish tomorrow morning.
If you are certain it is a 20 year old reflector then I would suggest in order:

Dismantling the reflector from the polarmount,
Removing the paint on the reflector surface,
checking the reflector sits more or less flat when face down on a really good level surface (a side on image will confirm if the dish is warped beforehand),
employ your 'technician' to straighten out the reflector should it need it,
verifying the feed arms are the correct length for a 240cm Famaval (I'm a bit worried it may not be one - I don't recall there being a hole in the centre when I installed them),
reinstall on the polarmount with as manu spacers as it takes not to distort the reflector,
string the reflector to verify it is straight,
fit the feed to the correct distance for a Famaval (though it may not be),
check performance with the existing LNB,
if still unsatisfactory then buy some panels to increase the diameter,
adjust the feedarms to the correct focal point,
paint the reflector with the correct paint.
 

Terryl

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After looking at some of the satellite sites, if he is looking at satellite 7 East (Eutelsat 7 B or C) then that dish is over kill, Satbeams reports a dish size for stable and error free signal on all European beams (in a central Greece location) to be at least a 1 meter dish, (some European beams show 55 cm) so it may not be an LNB problem but a swamping of the LNB with too much signal. (is possible)


Satbeams info.

Satbeams 7E.jpg
 
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John

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After discussing the issue with my technician here because this 2.40 has been installed 20years+ ago he was not sure
he mentioned that at that time there were in the local market famaval, mabo, dh, channel master etc ... so he was not sure 100%
I decided with my uncle to do again the painting this time colour white as i am afraid of the temperatures here in
the summer. Thank you all for your opinions. I will upload and image from the side of the dish tomorrow morning.

Just a quick comparison from here in Central UK, grab taken using the same GTCombo receiver, a 1.2 mtr Channel Master offset dish with an inexpensive pll Universal lnbf with approx 15mtrs CT100 coax.
What concerns me in your screen grab is the low 'Strength' reading as well as the low 'Quality' reading off your 2.4m reflector. Lnbf over saturation is in my mind as well.
See my comparison grab
..........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................

Screenshot 2024-03-24 19-50-39.png
 

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Just a quick comparison from here in Central UK, grab taken using the same GTCombo receiver, a 1.2 mtr Channel Master offset dish with an inexpensive pll Universal lnbf with approx 15mtrs CT100 coax.
What concerns me in your screen grab is the low 'Strength' reading as well as the low 'Quality' reading off your 2.4m reflector. Lnbf over saturation is in my mind as well.
See my comparison grab
..........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................

View attachment 155138
Yes, but if the reflector is warped it could be pulling in noise from anywhere, including satellites either side.

Key is warpage, painted surface, and confirmation of a matched feed........


But no fear, the o/p has a technician on speed dial.
 
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suedschwede

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The Famaval Dish are not particularly high quality. Many then adjusted the feed rods and achieved better results.
The predecessor may have experimented in the C-band and made changes to the original feed rods, many things could be so.
Famaval Dish Data

Bildschirmfoto vom 2024-03-24 21-02-55.png

Bildschirmfoto vom 2024-03-24 21-00-07.png

Bildschirmfoto vom 2024-03-24 21-04-33.png:)
 

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