Ariza AT 120 cm dish focusing poorly

[polgyver]

A few weeks ago I bought through Kijiji an used 4 foot Ariza dish - the price was $ 80, and an actuator 36 V 36" was included. The seller claimed that the dish was not installed, just stored in the basement.
I looked for such a dish for long time, planning to receive (finally!) some programs from C-band.
When installed, this dish was worse than my 36" no-name dish.
Annotated pictures will tell more:


Any other methods/tricks for re-shaping a dish?

 

[Cham]

I have a 1.2 fortec star dish that focuses poorly as well. It seemed to help to move (support) the LNB arm up a bit by using a string that I ran up though a hole at the top of the dish then down to the mount assembly at the back. This improved the signals quite a bit. Seemes the dish itself was too thin and weak to support the LNB arm even with the support rods. Adding the string likely causes distortion to the parabola as well but by better positioning of the feed point and removing some of the load from the support arm maybe it actually lessens the distortion.

I believe the Ariza dishes are built a bit heavier, but maybe has the same issue?

I have a picture of my dish mod somewhere, will try to find it. This shows where the string ties to the LNB arm...

 

[Conky]

I'm guessing the guy might have had a little 'accident' with the dish(thus the low price) or maybe it was just bad quality to begin with.

Did you try string testing it or laying it face down on the ground? any dents? I wonder if squeezing it horizontally would improve anything . The threaded rod braces might be the best solution as any attempt to reshape the dish with something like an English wheel might make it worse

 

[polgyver]

Thank you, Cham and Conky, for sharing your opinions. Most likely, Ariza is also thin and flabby like Fortec Star. Running extra supporting string, especially to 1-2 o'clock area, definitely worth trying.
I did string test of the dish, twice : on the mast and the "bowl" only, horizontally. The results are puzzling, as one contradicts the other.
I did not include these pictures in my first post, as it would be too many.
Also I forgot one picture showing less S/Q in the first post, so it will be shown here.

 

[jorgek]

As usual you have gone to great lengths to test and seup the dish. From the enclosed pics, especially the bracket holding the dish to the mast appears flimsy and undersized. I'm not surprised that the dish is out of round. Is that a typical bracket for a 4 ft dish?

 

[Cham]

Looks exactly like the fortec star dish I have.
There are better dishes available, the GeosatPro models have good reviews...

 

[pacificrim]

I corrected my Fortec 1.2 using 2 turnbuckles and some metal strapping. My old post is here:
http://www.satelliteguys.us/threads/310482-Another-Fortec-1-2-mod?p=3161923#post3161923

I have a separate ku and C LNB on this dish and it works great.

 

[polgyver]

As usual you have gone to great lengths to test and seup the dish. From the enclosed pics, especially the bracket holding the dish to the mast appears flimsy and undersized. I'm not surprised that the dish is out of round. Is that a typical bracket for a 4 ft dish?

True, everything feels flimsy and fragile. The sheet metal has the same thickness as in Raven (wild blue) dish, which is only 20" x 28".

 

[polgyver]

I corrected my Fortec 1.2 using 2 turnbuckles and some metal strapping. My old post is here:
http://www.satelliteguys.us/threads/310482-Another-Fortec-1-2-mod?p=3161923#post3161923

I have a separate ku and C LNB on this dish and it works great.

Your solution surely qualifies for praise from Don Lancaster (www.tinaja.com), who advocates so called "elegant simplicity".
Tried to do something similar, it happened I got some tubing lying around.
Just trying to bring the focal cloud to the smallest and most round shape.
Did not try receiver with meter yet.

 

[Titanium]

Surprised that there are any 1.2 Ariza dishes left! Ariza and there other DBAs were not known for being associated with quality, durability or reliability. They were all about cheap below market prices and turning a quick STB deal for the "clone of the month". Their companies seemed to be endlessly involved and associated with numerous legal problems. Google David Fuss / Ariza for some interesting reading...

Looks like a black cloud continues to follow: http://www.davis.ca/en/entry/litigation/unlawful-conduct-conspiracy-hsbc-bank-canada-v-fuss/

Ah, memories..... http://www.satelliteguys.us/threads/132792-Major-Free-to-air-Dealer-Raided-In-Canada

 

[polgyver]

Update with a few annotated photos:

 

[FaT Air]

Another simple elegant solution.
How much did you have to pull those points back?
(Don't think you'd gain much more by finding, and fixing, where that 'ding' is)

 

[polgyver]

Another simple elegant solution.
How much did you have to pull those points back?
(Don't think you'd gain much more by finding, and fixing, where that 'ding' is)

On the West edge, the turnbuckle was turned 4 times - it pulled the edge about 1/4".
East edge - 3 turns, pulled the edge about 3/16".
Probably the rectangular tubing also gave in a little, I have to check it with another straight bar.
But recently I got this idea to abandon the 3 member LNBF support from dish edges.
Instead, plan to fab the support attached only to H-frame, not even touching the dish.
True, the correction of one small "ding" is not worth bothering