channel 4

[dxsat]

Carleen- You would get better performance from changing your LNB, and you would lose channels less readily in rain.

The channel which may be causing the interference has only been going for a short while:

"2007-01-10
Badr 4 (26°E)
- A new channel has started in DVB-S Clear: Ghiras TV (Kuwait) on 12169.00MHz, pol.V SR:27500 FEC:3/4 SID:3 PID:32/33 Arabic."

It would only need a small amount of signal slightly off-axis to degrade the Channel four signal on the same frequency, particularly as the Arabsat signal is so strong where you are. Where I am, in Spain, a badly misaligned dish can still pick up a signal from the strong south beam of Astra 2.
The only remedy would be to use the best receiver and LNB, to reject the unwanted signal.

 

[carleen]

yes its a offset 2.7 dish not prime focus and its the lnb you showed in link. dont take me the wrong way i have very good signal and quality with my system on nearly all channels except 4 during daytime and of course when the weather is bad i lose channels

 

[iceman]

I somehow dont think the problem is interference from any other satellite...Why havent i (or any of my installations) had this problem??

An installer friend of mine has this 2.7m ofset dish in Nicosia and i did some test work on that dish with various LNB's and feedhorns....The best result was with a Sharp 0.3dB LNBF..
I even managed to lock on 10714H (ITV Anglia) on my meter but the channel was not watchable on his panasonic DSB40...still meter locked on it...Anyway,my point is not that this dish is good enough for 2D in Central or western Cyprus but with the correct LNBF signal could be seriously improved to overcome channel 4 problems....

 

[carleen]

ok thanks alot guys for all of your help....

 

[bignick]

ok my dish is 2.7 offset dish not prime focus dish and the picture you posted of the lnb is the correct one yes, im not saying i get millions of problems just channel 4 only in evening for a few hours where i thought i would get it 24 hours. the only problem i do get is when we have bad weather, i can lose some channels

OK, its an offset. First up the upsetting information.........you do not have a 2.7m offset, you almost certainly have a 2.4m offset - That information is what threw me into thinking its a prime focus. There is to my knowledge no 2.7m offset dishes made! The reason that you think you have a 2.7 is that your so called Engineer has measured it at its longest ie Top to Bottom. In fact it should be measured from side to side at the fattest part. If you were buying it in the UK with trading standards then it should be described as a 2.4m dish or at least as a 2.4mx2.7m

This link gives a little more insight into your problem:

http://www.satellites.co.uk/satelli...tion-tech/10361-size-2-7m-dish.html#post41351

However, that said, it really doesn't make much difference to you because you would be unable to receive anything from Astra 2D (BBC/ITV) and the dish you have will receive everything else that the 2.7m prime focus will.

I have no experience of the LNB that Iceman fits so I can't comment on it - Though if Iceman likes them then the smart money says they ain't too bad ;). They would also be good value for money - if it doen't work then you haven't lost much.
If you are feeling flush then I'd go for a C120 Invacom QDF-031 Universal Quad LNB. Do not fit the feed that Snap recommended - I fear he thought it was a prime focus dish too - this is the wrong Feed horn. There are special feed horns available for large offsets like yours which any sat engineer worth his salt will know about. You will probably require an adapter to make the feed fit the 40mm holder.

I would imagine that the correct amount of whinging to your sat engineer about misselling the 2.7m dish would get you a great deal on the LNB setup.

Its a shame none of us are more local to you...I'm afraid I don't know any other installer over there and I won't be going that way for ages.

Cheers

Nick

 

[iceman]

Nick
I agree with you,the dish is not 2.7m horizontally from its widest section...But many people make that mistake when measuring offsets..


Some offset feeds i tested with the C120 invacom on various offset dishes (including carleen's dish)..

 

[bignick]

Nick
I agree with you,the dish is not 2.7m horizontally from its widest section...But many people make that mistake when measuring offsets..


Some offset feeds i tested with the C120 invacom on various offset dishes (including carleen's dish)..

Yep, its the one on the far left of the picture that I personnally use on the Supral & Anderson offsets that I have worked on.

BTW I have also tryed the large adjustable feed from MP that you have on your 3.0m dish and find it significantly worse than the Large feed from Future. When I compared the two side by side they are very different dimentions.

Cheers

Nick

 

[iceman]

BTW I have also tryed the large adjustable feed from MP that you have on your 3.0m dish and find it significantly worse than the Large feed from Future. When I compared the two side by side they are very different dimentions.

Whats the difference? is the neck shorter on Future's feed or longer?

 

[bignick]

Whats the difference? is the neck shorter on Future's feed or longer?

The Scalar ring is a wider diameter, the rings in the scalar are wider apart and depth of the rings is slightly less too I think. I have one in stock if you want a photo posted (unfortunately I don't have the MP Sat one to compare but I have a 'standard' small one for comparison)

I think the neck assy bit is the same or similar

Cheers

Nick

 

[iceman]

Yes please...would be good if you could post a jpg of the two feeds together...

 

[bignick]

View attachment 10228

View attachment 10229

View attachment 10230

Yes please...would be good if you could post a jpg of the two feeds together...

Found another small type - only difference is neck length so I put one in with the feed also. I tried to take some with a ruler but they didn't come out so well, so dimentions for Large ring is 10.8cm Dia, small is 7cm Dia. Rings are 0.5cm apart on both scalars.

Hope that helps

Cheers

Nick

 

[iceman]

Thanx for the pics Nick
Difficult to say but by the looks of it,the large feed is the same as the one i have on my dish...still i can only be 100% sure when i measure the diameter tomorrow...

 

[carleen]

well the malloupas has lied to us then because they said its a 2.7 my dish is round and the lnb doesnt come into the middle if the dish its a little lower so is this a offset or prime focus?, some dishes i see the lnb is set right in center of the dish but mine isnt.

 

[bignick]

well the malloupas has lied to us then because they said its a 2.7 my dish is round and the lnb doesnt come into the middle if the dish its a little lower so is this a offset or prime focus?, some dishes i see the lnb is set right in center of the dish but mine isnt.

Once again Carleen....post a couple of piccies. Its real simply as long as you have a digicamera and a means to get the images onto your pc.

cheers

nick

 

[dxsat]

Sorry to hear that, I know it's no compensation, but this kind of deception is common round here, measuring dishes the long way and installing smaller ones than the customer has paid for. I have seen quite a number of people with 100cm dishes installed who believed they were 120cm ( and were charged for a 1.2 ), 1.7 instead of 1.8m, etc.
You almost certainly have a 2.4m offset.

 

[simonskyman]

Mallouppas do not supply 2.7m prime focus dishes anyway.they do the 2.4 famaval and the andersen 2.4 offset

 

[geoffrey]

This is a very interesting thread as I have found that whatever I do to my setup in Israel I can't get Channel 4.
I think that Badr 4 on 12169v is the culprit here.
With my prime focus 3.6 dish the beamwidth is about 0.5 degrees.
However, there are side lobes to the main point of focus with scalar feeds and I presume that because of Badr's signal strength these are being picked up.
I am using a Seavey feed matched to the dish and even this has not helped.

Incidentally there is a very low quality Channel 4 feed on 12129v. This is invisible to a Skybox but works in a FTA set with the right numbers from Lyngsat.

 

[dxsat]

I think the Badr theory was first raised by Zorba in January and is almost certainly correct. Any dish will have sidelobes and if the interfering signal is strong enough it will be received. There's absolutely nothing you can do about it. (Apart from move back to the UK, the usual daft reply from Digital Spy Forum members)

 

[iceman]

I still dont believe in this "badr" theory...If the geometry of the dish is OK and pointing at 28.2E,i dont see any reason why it should receive signal from a neighbour satellite..
I am also in Cyprus and i use a 3.0m prime focus dish...My channel 4 works 24/7 without any problems..

 

[dxsat]

Sidelobes are a fundamental property of any antenna.
See:
http://www.geo-orbit.org/sizepgs/Noise.html#anchor4293062540
Scroll down to "sidelobe discussion"
If you have a signal strong enough for a 60 cm dish entering a 4 metre dish it will be received and interfere with a weaker signal on the same frequency, even though the weak one is on the main beam.
Don't forget Geoffrey is in Israel.