Help: Which and what kind of C-band LNB should I buy?

[Sohaib_]

Hey guys I'm having a bit problem receiving C-band channels properly here in my area.

The common problem everyone here experiencing is the interference of WiMAX Internet towers. It's interrupting the satellite(C-band) signals and giving weak to almost no signals as most of you might already be knowing of the fact.

Previously I had 15ͦK C-band LNB installed and I replaced it with 50ͦK C-band LNB which did improved the signals quite alot but still I'm having problem with signals of some of the channels. My neighbour is using 100ͦK C-band LNB and having almost trouble free reception with very few occasional signal interruption.


So I was wondering if any of you could advise me on what kind of C-band LNB should I buy? Should it be 100ͦK one? Or is there any other stronger which bypasses the WiMAX signals? I heard 60ͦK LNBs are good as well but I don't have much technical knowledge about it so looking for some advise here.

 

[Analoguesat]

Hello and welcome to our forum


Have you tried shielding the dish in the direction of the nearest wimax tower?

 

[aceb]

Not sure any LNB will stop the problem, WiMAX in KSA is on 3.5GHz, with extended C band starting at 3.4GHz I'd guess all available LNBs will be designed to cover this lower limit and will struggle to cope with the strong signal from local towers. As Analoguesat suggests, probably the only way to reduce the problem is to shield the dish, traditional methods of notch filtering or phase cancellation aren't really practical on satellite.

 

[Sohaib_]

Hello and welcome to our forum

Thank you

Have you tried shielding the dish in the direction of the nearest wimax tower?

To be honest I'm very rookie at this stuff. I'm not sure what do you exactly mean by shielding my dish and with that? I tried to move the dish nearer to the wall it did improve the signal quality somewhat but still not sure what dish shielding is.

Not sure any LNB will stop the problem, WiMAX in KSA is on 3.5GHz, with extended C band starting at 3.4GHz I'd guess all available LNBs will be designed to cover this lower limit and will struggle to cope with the strong signal from local towers. As Analoguesat suggests, probably the only way to reduce the problem is to shield the dish, traditional methods of notch filtering or phase cancellation aren't really practical on satellite.

Thanks for you reply as well. Well I said I'm not really aware of what exactly shielding my dish means? My neighbour, as mentioned in the first post, is using a 100K LNB and he's having no difficult at all. We both use the same type of dish and receiver.

 

[Analoguesat]

If you can identify where the nearest Wimax tower is then see if you can physically block (or at least reduce) the signals coming into the system from the tower. Chances are the tower is somewhere out in front of the dish.

You will need to experiment with an old door, a second dish face, something like that, (on a calm day even a large sheet of aluminium foil held in place) and see if anything improves the situation for you..

The problem you are having is that the Wimax is transmitted on frequencies very close to the C-band stuff you desire, and the strong local signal just swamps the low power satellite signals. Any reduction in the external signals leaking into your system will help to some degree.

 

[Sohaib_]

If you can identify where the nearest Wimax tower is then see if you can physically block (or at least reduce) the signals coming into the system from the tower. Chances are the tower is somewhere out in front of the dish.

You will need to experiment with an old door, a second dish face, something like that, (on a calm day even a large sheet of aluminium foil held in place) and see if anything improves the situation for you..

The problem you are having is that the Wimax is transmitted on frequencies very close to the C-band stuff you desire, and the strong local signal just swamps the low power satellite signals. Any reduction in the external signals leaking into your system will help to some degree.

Thanks once again for the reply. I really appreciated it. Well there's wall like 30 meters away from the face of the dish so don't think it's causing the problem. I'll definitely try to experiment with the tips and advices you've provided.

 

[Analoguesat]

The signals may be reflecting off the nearby wall so its quite possible the tower is behind the dish!

Its a case of experimenting and seeing if you can find an acceptable reduction in external Wimax signal.


It might be worth seeing if there are any poor joints / connections in the cabling and if so remake them carefully. Also if you get some foil wrap some around the lnb (not the main face!) in case Wimax is leaking in through the casing somewhere. Be creative!

I rather suspect over the next few years Wimax will lead to many folks abandoning C-band.

 

[Channel Hopper]

Are you sure you mean 100k and not 10k ?

 

[aceb]

I rather suspect over the next few years Wimax will lead to many folks abandoning C-band.

WiMAX is the technology intended for our TV band so expect the same issues to start here with DTT in a few years time.

 

[Analoguesat]

Satellite only here, no DTT - I removed the aerial after Selkirk transmitter went digital as the signal is crap here! (despite the fact I can see the transmitted from the end of the garden!)

 

[Sohaib_]

The signals may be reflecting off the nearby wall so its quite possible the tower is behind the dish!

Its a case of experimenting and seeing if you can find an acceptable reduction in external Wimax signal.


It might be worth seeing if there are any poor joints / connections in the cabling and if so remake them carefully. Also if you get some foil wrap some around the lnb (not the main face!) in case Wimax is leaking in through the casing somewhere. Be creative!

I rather suspect over the next few years Wimax will lead to many folks abandoning C-band.

Well I guess the signal is bouncing of the side walls. As there's a WiMax tower to the left of my apartment building like less than half a mile away. The other day I took my TV and satellite on the roof of my apartment building and attached a different cable directly onto my LNB. So that's one thing ruled out. Still thanks for the ideas and the suggestions. I'll keep trying different things. Also learned few other things regarding aluminum foil and it's mitigation effects by searching Google


I would abandon C-band satellite if my home country TV channels were available on KU band but unfortunately they aren't at the moment.

Are you sure you mean 100k and not 10k ?

Absolutely sure it's 100k. Infact I'm thinking to make a small video of a minute or less of the area where my dish is located and perhaps you guys can point out something which I might not be doing correctly. If that's ok with you guys

 

[Analoguesat]

Ig you have a spare dish available put a c-band lnb on it and use it as a "direction finder" to narrow down where the interference is coming from. Then concentrate on that direction for your blocking attempts

Please let us know how you get on - any successes are always useful for others in he same situation.

Best of luck

 

[Sohaib_]

Please let us know how you get on - any successes are always useful for others in he same situation.

Best of luck

Well I tried some of the aluminum wrapping technique around my LNB that I found about yesterday night by searching on Google. It wasn't much of a use. May be a gain of 1% but that much gain and loss of signal is usual so not sure if it was because of that. I'll try to have a proper aluminum cone in few days time and let you guys know and it may be beneficial to others having same sort of problem.

Ig you have a spare dish available put a c-band lnb on it and use it as a "direction finder" to narrow down where the interference is coming from. Then concentrate on that direction for your blocking attempts

I do have a spare dish. I mean I can easily get one for very cheap price or may be even for free but I didn't get this direction finder thing. I mean how would it detect from where the WiMax signals are coming from?



Also I have made this video today in the afternoon. You can check out how my and my neighbours dishes are pointing at exactly the same direction while he's having no reception problem at all but me. May it's because his LNBs are 100K ones or may be they have some microwave filter in it. I don't really know. Here's the video. Sorry for my poor pronunciation and English.



-http://www.youtube.com/watch?v=l8emYgL-mqY







[warning]Live Link disabled - I tried to embed the video for you but failed![/warning]

 

[Lazarus]

Spent far too long trying to Embed Sohaib's YouTube clip but failed misearably ................... can someone with "the knack" please have a go!

 

[Analoguesat]

The {video} tags arent working - I'll notify Chris

 

[Lazarus]

Ah, now that makes me feel slightly better!

Thankyou for checking

 

[Analoguesat]

I do have a spare dish. I mean I can easily get one for very cheap price or may be even for free but I didn't get this direction finder thing. I mean how would it detect from where the WiMax signals are coming from?

Connect the c-band lnb to the dish and get it pointing at the signals. Move the dish around the yard / garden etc and see if the interference increases or decreases in any location. Make use of any existing shielding that you might have available.

If you are lucky you will be able to work out which direction the interference is coming from

 

[aceb]

Due to the strength of the WiMAX it might even be possible to aim the LNB directly at the source but remember 3.5GHz will be prone to reflecting off all sorts of surfaces. Have you tried obtaining an identical model LNB to your neighbours to see if that helps or maybe borrow his STB and LNB to use on your dish to see if that improves it too. You could try both together that would mean the cause is either dish placement or poor shielding on the coax.

 

[Sohaib_]

Connect the c-band lnb to the dish and get it pointing at the signals. Move the dish around the yard / garden etc and see if the interference increases or decreases in any location. Make use of any existing shielding that you might have available.

If you are lucky you will be able to work out which direction the interference is coming from

Oh I get it now. But if you have seen the video I've uploaded it's very difficult to move my dish around as the roof is scattered with way too many dishes and it wouldn't be possible to do that. What I did was move my dish towards the wall. It somewhat helped me to the signals of the desired channel but still some of the channels are having problems. So my main concerned as of now has been solved. Though I'll try to experiment different things from time to time.

Due to the strength of the WiMAX it might even be possible to aim the LNB directly at the source but remember 3.5GHz will be prone to reflecting off all sorts of surfaces. Have you tried obtaining an identical model LNB to your neighbours to see if that helps or maybe borrow his STB and LNB to use on your dish to see if that improves it too. You could try both together that would mean the cause is either dish placement or poor shielding on the coax.

I've had thought of asking him to lent his LNB for an hour or two, but at the moment he's kind of new so I'd give it sometime to get bit more friendly with him before I can ask him for that.

Thanks for the reply though