gibertini op 125l fe - a failure

[tom55]

recently got this dish from local supplier, unpacked - there are scratches all over the mounting equipment as well as several scratches on the dish edges (reflector surface looked good though), missing brackets, screws, bolts and nuts as well as instruction manual in the package.

the supplier told me they will send delivery service for a return and order a new dish. meanwhile i tried to mount it with the screws i had at home to see what kind of performance to expect and if it will be worth it at all.

before buying, i looked extensively in the internet for specs of different gibertini variants and people's expereinces with them.
officially, they list it as 41.9dbi at 11.7ghz, but several suppliers have different specs, some claiming 42.3dbi and a bunch of regional suppliers here in balkan claiming 43,4 db at 11.7ghz

i thought maybe it makes a difference if the dish is made of steel instead of aluminium, but after trying it out i don't think this kind of gain is technically possible.
looks like gibertini and their distributors trying to get rid of underperforming crap.

i set it at 7 east, where my TD110 is pointed to compare the two, no matter how much i tried to adjust op125 up/down and left/right as well as adjusting LNB, none of it helped. op125 came close or identical in SNR on 7-10 transponders to TD110 (which still isn't on a perfectly vertical pole, and i get ~1db more with TD110 after fine adjusting)

if this wasn't a design flaw, then these dishes are simply trash, not worth 30% of money they try to sell it for

 

[Beli1910]

It would be good if you could take a picture of the damage to the crossbar. The geometry of the crossbar is probably wrong. The Triax 110 cannot even be compared to the gibertini 125. I have both crossbars, as well as other types of Cm120, laminas 120, etc., and the gibertini 125 differs slightly from the others. For me personally, one of the better antennas in this size range, next to the Cm.

 

[tom55]

i also tried to look for comparisons of the two dishes done by dx enthusiasts, there was none or i missed something. only a few rough results at SU or some scandinavian forums all claiming op125 is at 5-7% signal advantage to TD110.
probably, even with smallest damage (geometry flaw) that quickly turns into -(5-7%)
also, TD110 was bought back in 2007. so it's not a new cut down version (reflect dimensions are approx. 112x103)
thus, i'm not convinced gib can perform much better and 5% is not really worth it

 

[Channel Hopper]

As above, take pictures of the dish as best as it can be assembled.

Elsewhere on this site there are posts mentioning incorrect Gibertini feedarms supplied by a dealer, yours may be one of them.

What gain figures are you questioning and - importantly - at what frequencies ?

 

[a33]

Did you string-test the dish already?

That is, if (and only if) the dish is meant to have a flat dish face?

Greetz,
A33

 

[EnoSat]

The difference between 110 and 125 is minimal, it is significant only under marginal income conditions

 

[Beli1910]

As far as I know, the dimensions of the gibertini 125 are as follows; Antenna size: 124.50 cm x 133.5 cm. Yes, and there is a noticeable difference in the signal between the two antennas, especially the one on the border of the Lock

 

[Captain Jack]

1.25m Gibs are excellent dishes. A well aligned (and non-warped) 1.25m will outperform any 1m dish out there.

I had a 1.5m Gibby which was warped and it performed worse than my 1.2m Channel Master of the time. Some careful bending back into shape resolved the issues.

 

[Channel Hopper]

1.25m Gibs are excellent dishes. A well aligned (and non-warped) 1.25m will outperform any 1m dish out there.

I had a 1.5m Gibby which was warped and it performed worse than my 1.2m Channel Master of the time. Some careful bending back into shape resolved the issues.

Yes, but a supplier pedding non-standard feedarms/parts as a functional product is going to kill the performance, and with it the reputation of the manufacturer.

 

[John]

Did you string-test the dish already?

That is, if (and only if) the dish is meant to have a flat dish face?

Greetz,
A33

My OP125 L uses a similar if not identical reflector to back mounting bracket with the six stainless fixing screws but did have an issue when assembling the two togther.
Stringing and lnb aiming point before the back mounting was fixed in place were spot on but once the reflector was mated to the rear bracket and screws tightened it warped the reflector and slightly mis-aligned the lnb aiming point onto the reflector surface which showed up when it was 'strung' again.
When just offering the two parts together it could be seen that the curvature of the rear bracket was just not exactly identical to the reflector curvature and caused a performance issue.... rectifying the mating fit made the performance spot on and performs exceptionally well on my Ka set up.

 

[tom55]

didn't thought of taking detailed pictures before, the entire thing is packed back now for return. i do not want to waste any more time with it.
feedarms appear to be fine, 2 pcs that form V shape. i tried to look carefully from several different angles, couldn't notice the dish is bent in any way.
about gain figures, TD110 should do 40.2 at 11.7ghz, so with this supposedly 43.4 dbi dish a gain increase of 3.2 dbi is supposed to translate into 15-20% signal increase. if it did 12-15% better it would still be fine for me, otherwise this is nothing

 

[Channel Hopper]

didn't thought of taking detailed pictures before, the entire thing is packed back now for return. i do not want to waste any more time with it.
feedarms appear to be fine, 2 pcs that form V shape. i tried to look carefully from several different angles, couldn't notice the dish is bent in any way.
about gain figures, TD110 should do 40.2 at 11.7ghz, so with this supposedly 43.4 dbi dish a gain increase of 3.2 dbi is supposed to translate into 15-20% signal increase. if it did 12-15% better it would still be fine for me, otherwise this is nothing

Where did you get that gain figure from ?

https://www.amfelectronics-eshop.com/adseshop/pdf-attachments/GIB-OP125L.pdf

OP 125 Series: large professional satellite TV antenna | Gibertini

OP 125 S series parabolic antennas for professional, condominium or remote applications that require large antennas.

www.gibertini.it

https://www.amazon.de/-/en/Gibertini-Aluminium-antenna-125-anthracite-charcoal/dp/B004IAX1JU

This thread may be of interest

Another one for the Arsenal: Gibertini OP 125 L

Found this in the local "loot". Originally priced at £20, it was put as "Free for collection" after a few days. Couldn't resist picking it up even though it was a 100km round trip through heavy rush-hour traffic. Got it home with no probs, even though it was just strapped to the roof-bars in a...

www.satellites.co.uk

 

[tom55]

Where did you get that gain figure from ?

regional webshops, for example

Under Maintenance

Zed d.o.o.

Zed d.o.o.

www.zed.hr

but there are several german sites advertising same value, e.g. Gibertini OP 125 L ab 279,00 € | Preisvergleich bei idealo.de

 

[RimaNTSS]

As far as I know, the dimensions of the gibertini 125 are as follows; Antenna size: 124.50 cm x 133.5 cm.

Those are physical dimensions. The size of the reflector (working area) is 121x130cm, so it is still 1.2m dish and, theoretically, can not perform better than any other 1.2m dish.
But, at the same time, manufacturer states that antenna has 21,3* offset angle, and this could be a question to @a33. Why not 21,4*?

 

[Channel Hopper]

regional webshops, for example

Under Maintenance

Zed d.o.o.

Zed d.o.o.

www.zed.hr

but there are several german sites advertising same value, e.g. Gibertini OP 125 L ab 279,00 € | Preisvergleich bei idealo.de

Put a request to Gibertini to ask, you may be advised the specification is incorrect, or that they are not official sellers of their antennas.

 

[a33]

Those are physical dimensions. The size of the reflector (working area) is 121x130cm, so it is still 1.2m dish and, theoretically, can not perform better than any other 1.2m dish.
But, at the same time, manufacturer states that antenna has 21,3* offset angle, and this could be a question to @a33. Why not 21,4*?

Well, the 121.0x130.0 might be in fact 121.04x129.96? Then the offset angle is 21.35.

So this might just be the effect of rounding numbers.


Another possibility: the offset angle is not calculated against top and bottom of the working area of the dish, as would be the 'proper' way, but against dish rim (which can have different heights, top or bottom).
There is no law against the latter, it is just a matter of convention (though then, of course, it would be better that they should (have) mention(ed) it...?).

For instance with a Visiosat/Cahors BiSat dish or Big Bisat, the bottom of the dish is deformed by the "exit hole" for the LNB arm. What would be the proper spec for offset angle: would you use the actual, physical bottom of the dish? Or the projected bottom, had there not been a hole for the arm?

Greetz,
A33

 

[RimaNTSS]

Or the projected bottom, had there not been a hole for the arm?

Of course, the projected one, I could never think differently.

 

[a33]

Of course, the projected one, I could never think differently.

Well, I'm not sure that I agree to the "of course".

For setting the dish elevation to proper offset angle, I would prefer to use the 'actual', physical bottom of the dish; not a projected, guestimated bottom.
For LNB aiming angle the projected bottom would indeed be more appropriate.

Just my humble opinion, though.

Greetz,
A33

 

[RimaNTSS]

For setting the dish elevation to proper offset angle

We are going too far. Originally, the question was about dimensions (size) of the working area of the antenna.

 

[Beli1910]

Sem pa našel v arhivu staro sliko dveh anten, ki sta bili takrat v uporabi. Kolikor vem so imeli gibertini že tovarniško pokvarjen focus - sploh stari giby 150. Z malo zračnosti je problem resen. Novi Lnb nosilci so bistveno boljši za uporabo kot stari fiksni.
------
But I found in the archive an old picture of the two antennas that were in use at the time. As far as I know, the gibertins had a faulty focus from the factory - especially the old giby 150. With a little play, the problem is serious. The new Lnb holders are significantly better to use than were old fixed.