Astra 2D in central Italy with a smaller dish!

[pjgregory]

Hi

I live in central Italy, near the town of Montepulciano in Tuscany, some 90km south of Florence. Several years ago I installed a 2.4m IRTE dish in the hope of getting BBC from Astra 2D, but with no success. I even spent over 500 euros to get an "expert" company to align the dish for me. Still no luck.

Reading through a lot of posts here, I began to realise that I could have a problem with the dish - several of the metal panels were damaged during shipping and at the time I did not realise how important accurate alignment could be. Lengths of fishing line stretched across the dish showed that it was distorted - there was about a 1cm difference between the highest and lowest lines at the center. Some weeks ago, I placed an order for a new 3.7m Prodeline dish which, being glass fibre, should be easier to assemble correctly.

Last month, I finally managed to get a proper ADSL internet connection to my house so I disconnected the 2-way satellite internet that I had been using. This left me with a Channel Master 1.2m wide offset dish that I no longer needed. This moring, as I had nothing better to do, I connected my Invacom 120 Quad LNB (the latest HD ready version) to the existing Andrews feed horn and realigned the dish to 28.2E.

On my Satlook NIT specturm analyser, the frequency specturm seemed at first sight to be better than that from my existing 2.4m dish. So I carefully set up the dish - especially the skew. For the first time I could see some evidence of signal peaks in the frequency range of Astra 2D. So back in the house, I swopped leads to connect the Channel Master dish to the Pace Skybox 2600 and there it was - a slightly pixelated BBC2 England !

A quick check established that I am just receiving tp45 at 10773H. Manually adding the transponder to the channel list gave me BBC 1 London as well. By luch time, the pixelation had disappeared - below is the BBC1 screen shot.

In the house, my Satlook gives a reading of 50.2db for the 10773H transponer using the 1.2m dish and only 38.9db for the 2.4m dish. Bearing mind that the 1.2m Channel Master dish has a published Ku band gain of 42db while the IRTE has 46db, there is obviously a BIG problem with my IRTE dish.

So if the my new Prodeline 3.7m dish has anywhere near its published 50db gain, then I should get about an 8db improvement over the Channel Master. Not only BBC1 on the H transponder, but even ITV and the real nivana - BBC HD. (Well I can but hope).

Many thanks to all the comments and tips that have got me this far.

PJG

[Topper]

Well that is certainly a result pj


Just goes to show how poor the performance is of the petal dishes hardly precision engineering

[pjgregory]

It is 7pm here now and my BBC1 picture is starting to break so it really must be on the limit of reception. When I was aligning the dish, my Satlook spectrum analyser showed a small peak for the 10773H transponder, but would not lock onto the digital signal. So the Pace 2100 must be more sensitive than the Satlook.

I forgot to mention, I am using output 2 of the Invacom Quad LNB as recomended by SNAP and others with about 40m of cable between the dish and the receiver.

[snap]

Really good to get a result like this, it helps to be using an analyser. ChannelMaster really are superior dishes, they'll always out- perform IRTE.
Prodelin are identical performance-wise to ChannelMaster, they just differ mechanically.
It's a bit late now but 3.7m sounds like overkill, a 2.4m Prodelin would probably give solid reception in your location, particularly as you're using sound methods and the right LNB.

[pjgregory]

Hi Snap

I am having second thoughts myself, but I have already paid for the 3.7m Prodeline and the dish should be in transit from the USA. I can console myself with the thought that I SHOULD get 24/7 reception all the year round and sufficient S/N for HD reception which is what I really want after all.

PJG

[Prodelin]

You have chosen the right dish, there is not anything that says "too big dish"

You will have great fun with that 3.7m as you can use it for C-band also and a great reserve for KU-band satellites.

Just get a nice ADL Ku/c-band feed to it or Seavey if you can afford it.

But try first to get a good signal on Astra 2D and look at how much reserve you got because the Ku/C-band feeds have some losses.

[Coviello]

It might be that a 2.40 cm Prodelin dish can do the job in your location.
However, satellites have got a relatively short life, and when they are getting older, their signal decreases. This means that a dish big enough today could not be enough tomorrow. So, it was wise to purchase a bigger one.

I have got a Prodelin 3.4 m dish. It was not easy to assembly it in a proper way. The assembly manual provided by the manufacturer was good but it did not stress the critical points. Unfortunately, if the assembly of the petals is not 100% perfect, the dish works as a smaller one. I had to replace the feed since it was not good for ku-band (like BBC on Astra 2d). In the end, the assembly was perfect, and the dish has the performance promised by its manufacturer.

In case, you need some advice, please send me a private message.
I visit Perugia many times, since my daughter is a student at the local university.

Coviello

[snap]

Sound advice, but I would disagree with the point about satellites ageing. They typically lose radiated power over their lifetime, but this is factored into the specification at launch, which could be around 130% of that needed to get predicted coverage on the ground. At the end of life, the satellite has no reserve left but has the same signal strength on the ground as it had at the start. If Astra didn't do this, many people in the UK would have severe reception problems at satellite end of life owing to the fact that minidishes are only just big enough. (And the fact that many Sky 'engineers' do a crap job)
Astra has to maintain constant power or the whole direct to home system would fall over.

[iceman]

I forgot to mention, I am using output 2 of the Invacom Quad LNB as recomended by SNAP and others with about 40m of cable between the dish and the receiver.

There is absolutely no way any one specific output will be stronger than the others on all LNB's...
I measure all four outputs after each installation to determine the strongest...
According to my experience it could be any one of the four.

[Topper]

There is absolutely no way any one specific output will be stronger than the others on all LNB's...
I measure all four outputs after each installation to determine the strongest...
According to my experience it could be any one of the four.

So in this particular aspect it is a case of suck it and see

[iceman]

So in this particular aspect it is a case of suck it and see

Exactly....
I work with this LNB on daily basis,so i have learned to measure all four outputs to determine the strenght of each output.
Having this info,i can plan their distribution better..(ie...give the lowest BER to longest cable run)

[pjgregory]

There is absolutely no way any one specific output will be stronger than the others on all LNB's...
I measure all four outputs after each installation to determine the strongest...
According to my experience it could be any one of the four.

From what I remember, the post about using Outputs 2 or 3 in preference was not about signal strength, but improved cross-polarization performance. I have re-read the post started by SNAP "LNB Comparison Tests" and found this comment

Here is the first test, on the Invacom Quad C120LNB, used extensively in weak signal areas. There is an ongoing discussion amongst the Cyprus members as to whether there is any difference between the four ports on the LNB.

You are right, it may just have been the specific unit - it would take very little time to test each output in turn.

PJG

[snap]

It is correct to say you cannot predict which is going to be the best port, but there is a tendency for the centre ports to be better. I have found this on the many Invacoms I installed. If a good meter or analyser is available, test all four for signal quality, but if not, use output 2 or 3 for your only or most important receiver.

[pipino]

From what I remember, the post about using Outputs 2 or 3 in preference was not about signal strength, but improved cross-polarization performance. I have re-read the post started by SNAP "LNB Comparison Tests" and found this comment



You are right, it may just have been the specific unit - it would take very little time to test each output in turn.

PJG

hi i wonder how did you get on with the Prodeline 3.70 monster dish ,there is some chaps in the north african desert of the sahara trying to get a 6metre dish (patriot i think) to get full astra signal ,i´m still waiting for the reports