Hi Guys
I'm about to fit my first set of extension petals to a 2.4 Famaval next week. If anyone has any advice or hints and tips on fitting them and any adjustments afterwards then I would appreciate it.
The dish has the wide adjustable feedhorn with quad invacom just now and is on a fixed mount.
Cheers
Nick
Are you fitting them yourself?Originally Posted by bignick
Me and my good friend
I'll try and be brief
1/ Tip the dish onto it's back if you can (ie pointing skywards) not sure if you can do this with a fixed mount.
2/ Fit all the petals but leave all bolts loose so they hold in place.
3/ Tighten the bolts between the petals first before the ones between the dish and petals. This is because the holes that are on the dish side of the petal is oval shaped allowing for a bit of "play". This should also pull the shape together.
4/ All the time while tightening the bolts check that the surface of the petal flows smoothly onto the dish. You may need to tip the dish back down to check this.
I have fitted over 30 of these dishes now with petals and even still sometimes they are a B*st*rd to get to fit right.
With the extra weight of the petals the dish becomes unstable in the wind and tends to wobble. We fit steel wire from the bottom of the back mount (not the dish) and tighten with a Turnbuckle fitted to a hook bolt fitted into the ground. This does not need to be tight as what it actually does is stop the dish lifting.
We then fit the same arrangement on either side of the back mount and this stops side to side wobble. We also use these "adjustments" to peak the dish as when you tighten the turnbuckle the dish pulls to one side or the other.
Can't think of anything else but if my gibberish does not make sense let me know and I will send pictures.
Good luck
Triggs
Cheers for the info Triggs
You make perfect sense - it seems like a very logical approach to me.
One or two pictures of the steel wire supports would be helpful, and if you know how long they are including the turnbuckle then that would be a great help when I make them.
Thanks again
Nick
Good advice trigger.Be careful how you handle the petals as they can bend easily.While the dish is pointing up to the Sky you can see the shape of the dish and if it is deformed.Run your hand along the petal joins and feel if one is higher or lower than the adjoining petal.the problem is when the petals are in place,you cant get near the lnb to do final adjustments without touching the dish.The slightest touch moves the dish.I usually put 2 stabilisers from the horizontal part of the mount,one on each end to the ground but after the dish is aligned to maximum signal,but you have to be careful because as you tighten these,the dish/mount can pull either direction.
good luck.
Sorry for interrapting your chat.This for simon.Focal point is the same length.What about the width of the feedhorn is it ok to use the wide one instead of the smaller?
Considering the diameter & the depth of the dish is increased..shouldnt the focal lenght also increase?
I have in my possesion an old brochure for famaval dishes and it says that the focal length is the same(93cm).My theory is that although the depth and diameter increase,the f/l calculation should still give the same result.But i have never used the calculation though, never sure where to measure exactly the diameter of the dish as the edge curves.Brochure says the dish is 3,1m diameter with extensions.Some people say 3.2m in their adverts.
simon, which feedhorn do you use after you put the petals?
The focal length of the dish cannot change, as you're not changing the curvature of the inner part. This will continue to bring the signal to the same focal point. Just think of those drawings of parabolas you did in school...
It will be a large dish with a short focal length.
The ones i have done,which were a while ago,used the original white one that came with the dish.But i would like to know if the adjustable version is better.Once the extensions and stabilisers are on its a hassle to change lnb/feedhorn because of the way the feedhorn bracket comes apart.I havent installed a new 2.4 famaval for over a year,its all 3m and some 2.7m now.I suggest you put the adjustable on now so if you need to take it out you just loosen a screw and slide it out.
Simon
I think we will try both the large and the smaller feedhorn ends in place. Maniacop had heard that although the petals made the dish larger, the narrow adjustable feedhorn worked better! Since we don't yet have this as gospel, and I now have a decent spec anni, we will spend some time and report back our findings to you good people.
Cheers
Nick
Thats good of you Nick.I think the best test is if you can make ITV Yorkshire (10.891)work either morning or evening.Thats the difference between a good result and better result.What measuring equipment are you going to use?
We will be setting it up with a satlook NIT (assuming I can work out how it works or a lacuna if I can't) We will then do any really fine tuning on the digibox itself (pace 2600). Maniacop is an absolute genius at this - really patent and knows how to get the most out of the famaval!!!
Cheers
Nick
Probably teaching you to suck eggs but set the Lacuna to look at H or V Low depending on what is the strongest in your area. Over here we can't get V Low so we peak up on H Low. Promise to take my Camera to work tomorrow and get you some pictures. Have even placed it by the front door so I don't forget it.
Good luck and keep us informed
Can t wait to see your pictures trigger.As they say ,"one picture is a thousand words"
Pictures
Find attached the pictures
Note this dish was installed in the morning and the concrete base was due to be done in the afternoon. Normally I would recommend doing the base first but it's football this weekend and everyone is in a rush!!
Pic 1 - Shows all 3 ties to the ground
Pic 2 - Close up of how cable is attached to back mount
Pic 3 - Close up of what we call a "Turnbuckle". As you turn it, it tightens both ways (left hand thread on one side and right on the other)
Pic 4 - The downward stay - funny angle I must admit - Different guage wire but it was all the local supplier had left!
Pic 5 - Note the bolt in the middle of the mount. We drill and Tap the mount and put a bolt in each side because we have found the mount will still turn on the pole no mater how tight you do the 3 bolts.
Hope this all helps
Let me know if you need more info, pics etc
Triggs
Hi Trigger
Thanks for the photos they are a great help.
I suspect that we will only need the two at ends of the horizontal elevation pivot bar as we don't have the dish cranked so far over to the vertical as you do (well not for 28.2 anyway)- ours sit at 50 degrees and therefore don't show so much metal to the wind! Simon, is that infact the case here?
We have problems with tightening the clamps too but generally together with the rear bolt you get enough to stop the local wind upsetting things!
Why do you need a concrete base? Is the rooftop not thick enough? How do you fit it 'after the fact'?
Once again, many thanks for the info and input.
IOU 1 Keo (sorry no San Mig here)
Nick
We fit the base because we do get some strong winds here and the local buildings are a bit dodgy. Basically we drill more holes into the roof, fit some steel reinforcing bars and pour a 1M X 1M X 30mm base around the base of the dish in a wooden frame.
How has things gone anyway?
One day I will come for that Beer. Keep one cold for me!!
Am fitting them in just over a week!
I'll update you all then
Cheers
Nick
I'm pleased to say that myself and maniacop fitted the petals today and it seems that it is sucessful so far. I have just been on the blower to the happy customer who reports that the 7-9pm weak spot was sparkley free - picture on bbc and itv solid as a rock. Thanks to all concerned.
I aplologise for lack of pics, they will come in the next 24hrs I hope.
As usual, even though it seemed a successful instal, there are questions.
We sat it up exactly as trigg and simon advised - ie petal to petal first then petals to dish and all was ok. We got alignment petal to petal perfect with little problem. Petal to dish perfect alignment is not possible is it? Pushing up on the petals from behind with the fixing bolts loose still leaves the petals sitting 1 or 2mm lower than the dish - is this normal? It doesn't seem physically possible to push them into line with the dish! results speak for themselves ie perfect picture - but will this be the case in the hieght of summer?
Before we started we checked with the satlook and we were getting almost nothing - afterwards we got three of the four lights lit constantly - but not the 4th therefore we couldn't check SNR - is this normal for cyprus? We adjusted further by setting it to an astra 2b transponder (11900) and got it touching 9.0db but usually about 8.0db at 1600hrs local - is this ok -it was hard to tell as it was really gusty - those dishes REALLY do move in the wind BTW we used three wire rope stays; 2 didn't seem enough (plus I made 3 anyway
Feedhorn - It became obvious to us when we swapped the large diameter feedhorn disk for the small diameter one that the large one was the best. I'd say it was 1/2db better than the small one! We made efforts to setup the feedhorn as close as possible before the petals went on so we didn't have to screw with it too much afterwards. We didn't adjust the Focal distance afterwards. It wasn't the safest job to get to the LNB after the petals were fitted (good call simon)
Photos coming
Cheers
Nick
Hi Nick
I have no experience with Framaval dish or its extensions but plenty on the Jonsa petalised dishes.The original holes on Jonsa dishes very rarely match for a smooth/level joint so i ALWAYS enlarge them or drill new holes..I dont see why this method shouldnt work on Framaval..
Lets wait and see what Simon says..He has experience on these dishes..
It seems you did a good job if it works all night.Well done guys.What about 8-10am?
Does ITV Yorkshire(10.891H) work after 7 pm?And ABC1 (channel 281).
I just started using the satlook recently(because i lost my roversat) and i cant get the "4th light" on or s/n readings,bloody annoying so i rely on the spectrum and span reading.
One other tip is to take off the bottom petal so you can get closer to the dish and adjust lnb for final readings without disturbing the dish,then carefully put petal back.
As for not been in line,I had that problem on a couple of dishes but not a big deal as long as the final shape is not warped,you can tell by looking at the dish from a side ans bottom view.do you have the old beige dish and new grey petals?The grey dishes have a slightly different edge that fits better to the petals.
This is one way to stabilise the dish.Only one bar was used at that time to see if it was enoughand it seems to hold well so far,except if you rock the dish by hand with force,the dish moves back and forth,not left to right,but its okay in strong wind.
There are currently 1 users browsing this thread. (0 members and 1 guests)
Posting Rules
LinkBack URL
About LinkBacks
Reply With Quote
Bookmarks