LNBFs with LTE/WiMax filters - Why?

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The C-band range usually is around 3.4-4.2 GHz.
I see that the Titanium Satellite PLL range come with a LTE/WiMax filer equipped variant, filtering out stuff < 3.7 GHz.
Can someone explain why the low-pass filtering of <3.7 GHz is needed?
Checking up on LTE, the fequencies used are all < 1GHz.
And WiFi operating frequencies are near 2.4GHz and 5 GHz.
What's going on?
Is it even applicable in Europe?

EDIT: Thread title should end in "Why?" rather then "How?"
 
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Well that screws any earth stations inside the M25 (I did some work on a teleport near Russell Square yonks ago)
 
The adjacent signals can definitely cause a problem.

Where I live it's a problem for terrestrial reception. Here, the BBC HD multiplex on channel 60- (785.834MHz) (right at the top of the new UHF band) suffers especially due to several LTE 800MHz cells on top of a tower block a few hundred metres away, in the same direction as the Malvern transmitter.

Luckily with a decent filter the signal is now all fine, but without it you can see a high bit error rate and break-up!

I guess as these technologies, and the bands they use, expands - we'll see more and more filtering needed!


Sent from my iPhone using Tapatalk
 
WiMax interference... indicated...webp I have a video taken from my analyser of what i think is WiMax interference on a Cband signal that is possibly coming from one of the cell masts down the road from me. I'll upload it asap.
This still picture indicates the possible intereference. The dish is looking at 0.8°, even when the dish is moved way up in elevation or pointed in any direction the interfering signals are still there.
I need to switch off every bit of equipment in the shack and just have the Cband lnb connected directly into the Promax to eliminate the possibility of the intereference coming from another source say within the shack.
The real-time video shows the situation better.
...............................................................................................................................................
 
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3km from transmitter.

43W , reception impossible.:-toilet

43Wscan-prijemvprdeli.webp
 
John said:
View attachment 106179 I have a video taken from my analyser of what i think is WiMax interference on a Cband signal that is possibly coming from one of the cell masts down the road from me. I'll upload it asap.
This still picture indicates the possible intereference. The dish is looking at 0.8°, even when the dish is moved way up in elevation or pointed in any direction the interfering signals are still there.
I need to switch off every bit of equipment in the shack and just have the Cband lnb connected directly into the Promax to eliminate the possibility of the intereference coming from another source say within the shack.
The real-time video shows the situation better.
...............................................................................................................................................
Click to expand...

Youtube vid here ....


Video shows dish being raised way up in elevation to loose any sat signal.
 
mar-val said:
3km from transmitter.

43W , reception impossible.:-toilet

View attachment 106180
Click to expand...


Not good at all. I'm wondering how effective a Cband lnb with WiMax filtering would really be ?. Can be a quite expensive trial and error exercise me thinks.
 
I dont think it would help.interference is very strong. Frequencies around 3667 and 3710(this is weaker, but is)on all orbit are not receivable. Dish is on the roof.
I have second big dish in my garden, in shadow of house and trees, there is the interference much weaker.

Maybe I will try that LNB sometime.:rolleyes:
 
John said:
I'm wondering how effective a Cband lnb with WiMax filtering would really be
Click to expand...
I presume it's a narrower version of the filter I wired out on the extended band one I modified. In which case, it may help in mild cases but not in mar-val's.

mar-val said:
I dont think it would help.interference is very strong. Frequencies around 3667 and 3710(this is weaker, but is)on all orbit are not receivable. Dish is on the roof.
I have second big dish in my garden, in shadow of house and trees, there is the interference much weaker.

Maybe I will try that LNB sometime.:rolleyes:
Click to expand...
I'm not sure even this will help as your interference is right on the edge:
C Band Interference Elimination Filter, 3.7-4.2 GHz, FLT-MFC-13961W | Viking Satcom
You need something like the very sharp ones or notches from here but they will be $$$
C-Band Receive Filters
Filters will not help you with 3667. Interference cancelling may work at $unknown
Try shielding? A big sheet of metal or a spare dish? ;)
 
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