Breakup in Ku band

[timmyturner]

hi
I have(we have) a big problem here. I found this forum and i thought i can solve my problem.
I live in iran. as u know(u here in news) the government send noise to breakup ku band signals. (i think it should be TI) (often from 12pm to 12 am)
anyway. i found some techniques to avoid/reduce this issue..(covering LNB with a piece of aluminum , etc). but these were not useful.
know, i came here and im asking u , do u know how i can reduce this noises?
(I use a 90 centimeters dish , a ku band starsat LNB(SR-320 max) and a starsat x-95 receiver . i want to reduce or remove noises on Hotbird 8 and nilesat)

:up

 

[SatelliteAV]

to SatelliteGuys!

The new technology era of "If you don't want them to learn, burn the books".

A few suggestions to minimize the terrestrial noise.

• Place the dish low near the ground, between buildings and not exposed like on a roof. The buildings help protect (attenuate) the dish from terrestrial interference.
  
• Attach 20-50cm metal flashing around the edge of the dish to form a tube. This will help minimize noise from entering the LNBF from the side angles.
  
• A dish with a deeper concave surface will have better sidelobe noise rejection. A larger dish with tighter beam pick-up pattern will amplify the desired signal and reject signals off axis.
  
• Inline notch filter to eliminate most of the band with the exception of specific transponders that you are interested in. This will help minimize the noise overloading on the tuner.

Good luck on your project. Let us know your solutions!

 

[Phottoman]

Welcome to Satelliteguys.

I don't know if this will help, but back in the late 1980's I lived in the desert very near a US Air Force Base, and every evening, the TI would get so bad that there would be virtually NO signal readable on my C Band receiver.

It was a VERY reliable interference that would go from about 1800 hours (6 PM) until close to midnight.

I had to build a 10 foot by 10 foot screen, aluminum mesh window type screen. I built a 10 foot by 10 foot frame out of wood 2X4's, then stretched the aluminum screen across the entire frame. Three of us moved the screen around until I found the (almost) perfect place to set it up. We built what looked like a lean-to with framing coming off the top and mounted the whole thing in the ground to hold this screen up against the wind.

It worked pretty well for the few years I lived there, and I sure wish I had pictures to show you.

I'm pretty sure that was overkill, but the idea might get you started on placing some screening between your dish and the possible source direction of your TI.

I hope this idea helps.

Phottoman

 

[hwm]

Since you most likely don't want to attract attention to your shielded dish, I would suggest you place it inside a building, aimed out a window at the satellite you want to receive. Build a box of grounded wire mesh or solid metal around the dish, leaving an aperture open for the incoming satellite signal.

A small shed with internal metal screen grounded to earth, and a plexiglass window properly oriented towards the desired satellite would be another idea.

Adding a cone-shaped metal shield to the LNB should help reduce TI also. Ground the shield and the entire dish to earth.

Any type of shield you try should be grounded to earth.

A slightly larger dish with a stronger received signal from the satellite might help to overcome TI.

I suppose if you wanted to go all-out; dig a hole in the ground and put your dish down in the hole, aimed up at your sat, and cover the hole with a plastic tarp.

If the TI is ground based you can probably find a way to block it, but if it originates from an aircraft at high altitude, it may not be possible to screen it out.

 

[1ADAM12]

If you have access to a roll of copper or aluminum window screening, you could make a 90cm cylinder that extends beyond the lnbf by 30cm. Grounding your dish and the screen would help.

 

[timmyturner]

here is a view of our roof

Unfortunately i cant place the dish near ground, because i live in apartment. however there is a dome roof i can use as a hard shield between my dish and the source of TI.

I will try this tomorrow after my school. I will tell u the result.

but there is a question for me. as u see in map, the BTS antenna ( source of TI) is in front of my dish. if i want to use a mesh, i have to put this in front of dish. will not this block the dish?

and another Q. the dish is on roof and is connected to the surface of roof. isn't this enough or i have to connect it to earth connection( roof is connected to the walls and walls are connected to the earth)

 

[timmyturner]

right now one of my friends recommended a type of LNB.
it is:
Ultra Low Noise Inverto LNB
Single High-Gain Low Noise 40mm LNB
HDTV DVBS2 Compliant 0.2dB
i dont know. maybe i will try this LNB as the final method.

 

[Babadem]

Sorry, I don't have any solutions, but this is a very interesting topic.

 

[hwm]

One thing to remember when shielding your dish is that offset dishes, which are by far the most common type of Ku band dishes, "look" 20- 25 degrees above the dish edge surface plane.

If your LNB is carried low on the dish, not in the center, then you have an offset dish. Dishes with the LNB centered on the dish are called "prime focus" and "look" directly at the target satellite.

The large dish in my avatar picture is prime focus. The smaller dishes are all 22 degree offset.

Use a protractor to make a 22.5 degree cardboard template to help visualize this offset look angle and move your dish as close in behind your shielding structure as possible without blocking its view of the satellite.

 

[jogon64]

It is an interesting topic indeed, but would you not get in serious trouble if caught trying to avoid government-sent TI?

Kinda like hacking over on this continent, but perhaps with worse penalties.

What programming are you trying to get anyway that´s worth this risk?

 

[timmyturner]

i use a prime focus dish

 

[AcWxRadar]

hi
I have(we have) a big problem here. I found this forum and i thought i can solve my problem.
I live in iran. as u know(u here in news) the government send noise to breakup ku band signals. (i think it should be TI) (often from 12pm to 12 am)
anyway. i found some techniques to avoid/reduce this issue..(covering LNB with a piece of aluminum , etc). but these were not useful.
know, i came here and im asking u , do u know how i can reduce this noises?
(I use a 90 centimeters dish , a ku band starsat LNB(SR-320 max) and a starsat x-95 receiver . i want to reduce or remove noises on Hotbird 8 and nilesat)

:up

here is a view of our roof

Unfortunately i cant place the dish near ground, because i live in apartment. however there is a dome roof i can use as a hard shield between my dish and the source of TI.

I will try this tomorrow after my school. I will tell u the result.

but there is a question for me. as u see in map, the BTS antenna ( source of TI) is in front of my dish. if i want to use a mesh, i have to put this in front of dish. will not this block the dish?

and another Q. the dish is on roof and is connected to the surface of roof. isn't this enough or i have to connect it to earth connection( roof is connected to the walls and walls are connected to the earth)

right now one of my friends recommended a type of LNB.
it is:
Ultra Low Noise Inverto LNB
Single High-Gain Low Noise 40mm LNB
HDTV DVBS2 Compliant 0.2dB
i dont know. maybe i will try this LNB as the final method.

Timmyturner,

Welcome to satelliteguys!

This is definitely an interesting subject, to say the least.

First of all, is the BTS transmission set to purposely interfere with your signals? Or is this simply a coincidence that it is so near and so strong of a signal to you that it interferes that much?

If it is being done on purpose to prevent you from receiving a good signal and to irritate you, you may have to implement some stronger counter-measures.

Looking at your image of where your dish is set and where the BTS broadcast is eminating from, (which was a very excellent image to help explain the situation) I would say first of all that moving the dish to the right side of the structure in the center of the roof would definitely be helpful. The wall of that structure would serve as a natural sheild to some extent as it would be between your dish and the BTS signal. I would try this notion first as it is fairly simple just to run a longer cable over to that particular location (rather than build some sort of sheild enclosure). If you can get away with making use of something that is already present, that would save you some work.

Regarding your question about grounding to earth or grounding to the structure of the building, that really depends on many variables. If the building you live in has a superb metal frame and that metal frame is well grounded to the earth, then you are probably in excellent shape by simply attaching the ground to the building's metal framework. However, I don't know what you have for local regulations regarding electrical codes. This may not be legal for your city or state/province or national laws or codes. Especially if you are living in a multi-family dwelling or apartment complex with others whose safety may be concerned.

The most important purpose for grounding is to redirect any lightning strikes away from the building and especially away from the interior of the building and shunt it to earth ground for safety reasons (fire and shock).

However, proper grounding can be an extremely in depth subject and many people make an entire career of the subject of grounding for reasons beyond just safety concerns. It is a fascinating and often illusive field of endeavor.

The Ultra-Low-Noise LNBF would be a benefit, but keep in mind, when a manufacturer states a low dB noise rating for their LNBF, they are generally referring to the noise that the amplifier within the LNBF itself is generating (so a low noise LNBF is simply a much "quieter" piece of equipment). This rating is not exactly related to external noise issues like TI. All amplifiers (such as an LNBF) generate their own ambient noise, the less noise they generate, the better.

Other factors and ratings are more critical to reducing the interference from other sources. Mentioned previously were the geometry of the dish (a deeper dish or the focal ratio F/D ratio) and side channel rejection of the LNBF. The higher quality of an LNBF often, but not entirely, means that many of the advantages that you are seeking will come hand in hand. Of course, that usually means more expensive equipment. This is not always true, but in a general sense it is fairly accurate.

Your access to the rooftop of your apartment could be a nice benefit in several ways. First of all, it elevates your dish and provides you with a better LOS (Line Of Sight) for the satellite you desire. But, also... it isn't that easy to view from the street and you can conceal it better.

If you have permission to do so, you could conceal your dish as part of an aviary (did I spell that right?) Many people keep doves and pigeons on rooftop aviaries, so you could disguise an enclosure as such and use metal screens to block side interference signals with no one being the wiser about the installation. Obviously, you wouldn't want to block the signal you desire from the satellite, so care in the design of the shielding is necessary.

There are many possibilities for you to incorporate to accomplish the task of reducing the interference from the BTS signal. You may have to use them all. Each one may provide you with a small improvement towards your objective.

I think that I speak for everyone here when I say that I will be extremely interested to hear how it all works out for you and which measures that you utilize to fix this problem. It is very interesting indeed.

I sure hope that you enjoy your membership with us in the world of satellite fun! It is a great hobby and it is a great experience for everyone.

RADAR

 

[timmyturner]

It is an interesting topic indeed, but would you not get in serious trouble if caught trying to avoid government-sent TI?

Kinda like hacking over on this continent, but perhaps with worse penalties.

What programming are you trying to get anyway that´s worth this risk?

The programs i like to watch are:
Hotbird:
viva polska
Russian music box
PMC (Persian music channel)
K2 (i like to watch Due fantagenitori (aka The fairy oddparents))
Nilesat:
Fox Series (which shows American TV shows like Greek,Kyle XY,The simpsons,Ugly betty and etc freely)
MBC Package:
MBC Max (Shows Romance,Drama,Comedy and family movies of Holywood freely)
MBC Persia (shows same movies as Max but provides persian subtitle+90210+FRINGE+The harpers island+ etc)
MBC Action (doesnt need to explain)
MBC 2 (every kind of movies)

I watch all of this freely.

 

[timmyturner]

Hi AcWxRadar. i couldn't read your post fully. it's 1:30 AM in iran and im too sleepy to watch the screen of monitor.
I will answer u tomorrow. but about the BTS antenna i had to tell u that the government attached something to this antennas which sends noises . i will show u a picture of this antennas tomorrow.

Good night/day/evening/what ever.
Thanks for your friendly behavior.

 

[AcWxRadar]

Hi AcWxRadar. i couldn't read your post fully. it's 1:30 AM in iran and im too sleepy to watch the screen of monitor.
I will answer u tomorrow. but about the BTS antenna i had to tell u that the government attached something to this antennas which sends noises . i will show u a picture of this antennas tomorrow.

Good night/day/evening/what ever.
Thanks for your friendly behavior.

You are welcome,

I will look forward to your next response.

Just for your information, please be careful with the language you use. Even if you try to conceal it with asterisks and such, this is a family group and we keep it clean. I thought that you should be aware so that you didn't offend anyone and make a bad impression from the start.

Take good care and chat with you soon.

RADAR

P.S. (an EDIT): The thing about bad language is not censorship here, not something like a ban against public speaking or religion or comments regarding politics. It is just that it is not appropriate for any children or sensitive people and we have all people here. We also avoid heated debates regarding politics and religion as that is not our purpose. Our purpose is solely for the fun and enjoyment and technical issues surrounding satellite television/radio and electronics/physics or other fun stuff. We would rather keep all other issues aside in order to maintain this specific forum soley dedicated to its main purpose. There are other areas of this forum/site where you can discuss politics and social issues and ills if you wish to, but even there, we discourage the use of any profanity. We can all get our message across without it.

 

[timmyturner]

here are the reports:
1. I Got F in my test.
2.I moved the dish to the right side of the dome roof.but it was not success full.even it couldn't reduce the noises. the red lights shows the places i placed my dish.
3.i placed my dish back. there i tried to set my dish again and i found some amazing results. There are more than one noise source around us. when i was setting the dish, I found some signals coming from unknown places.the blue lines show the azimuth of them.
4.i moved my dish a little bit over the correct settings. although it reduced the quality of signals, but successfully reduced the noises.
of course i Couldn't do anything for hotbird or nilesat yet.all i have done was about Eutelsat W2. because its signals are really powerful.(Eutelsat is my another dish.I've two dishes and 3 LNBFs.Eutelsat shows the official programs of iran)

The BTS antennas

and a picture of my dishes

i have a question. as u see there are more than one source.can i place a big cage like aviaries around my dish (the whole sides of it,even in front of it) which is covered with aluminum or metal mesh connected to the earth?

Note:
-Plz X-cuse me if i used any taboo word. u known my native language is not English and i exactly dont know where and how i should use which words
-speaking in a foreign language is hard for me. reading foreign terms are harder and understanding your meaning is the hardest.
(LOL.i was joking )
-I got 80 of 100 in my math examination

 

[timmyturner]

I've read your long post (#12).
It was really useful and i could learn many things.Thanks for explanation
im interested to know that is this illegal for you to use satellite in your country?(because you have written about hiding the dish)

aviary (did I spell that right?)= that was right

i found some amazing information about there (i didn't know u keep pigeons on rooftop too)

 

[SatelliteAV]

Your dish type is a prime focus, meaning that the LNBF is in the center of the dish. This type of dish is more likely to have problems with ground based interference.

If you can find a source for an offset dish like this photo below you will most likely have better results. An offset dish will reject more of the ground based noise as it will reflect away from the LNBF.

No, it is not illegal to have satellite dishes in the USA, but often local housing requirements or local government, (or a wife - ) state that the dish cannot be larger than a certain size or be visible from the street / neighboring home. Often our forum members develop very creative ways to hide their dish from public view!

 

[laseradam]

Try this.
In the picture of the BTS antenna. Tape a string to the center of your dish. Not the LNB.

Pull the string tight and aim the end of the string at the antenna that is causing interference. Make a square frame with metal windowscreen or some piece of metal and set it on a pole or something so that it covers up the view of the antenna tower when standing behind the dish. Then ground the screen.

Or you could drill a tiny hole in the very center of your dish. Stand behind the dish and use a laser pointer to aim thru the dish and at the antenna. Put your metal grounded screen where the laser pointer aims over by the edge of the roof wall.

 

[laseradam]

Also the ofset LNB seems to be aiming directly at the Antenna tower!

Measure the angle from the center of the dish to the offset LNB. Then using that same angle from the center of the dish to the other side if the dish look from the center of the dish down that angle and I think you will be close to aiming directly at that antenna.

What is the elevation setting on your dish mount?