Interference Issues on "C" Band

[Simon]

A business partner in Africa owns a 2.4m "C" band antenna that he utilizes for VOIP and Internet services. About a week ago, Wimax was introduced in the City where he lives. Indeed, the Wimax base station is about 1km away from his location. He has since been experiencing interference - scpc errors. Anyone with some ideas and a possible solution?

Thanks,

[Jose Pimentel]

Extended C band is 3.6 - 4.2 GHz
Super Extended C band is 3.4 – 4.2 GHz.
If your friend is receiving only in the Extended C band you can use a band pass filter to solve your problem or one of the new LNB that have been designed for this specific problem that include the filter. Look for equipment with characteristic similar to this:

Filter model 7893D from Microwave Filter Company

Personally I have used this band pass filter with 100% success rate as near as 25 mts. away from a Wimax BS with an EIRP 52 dBM. But I must say this is the expense solution. If you look hard enough you can find a cheaper substitute.

[Sandeep Sharma]

Its a common problem, in this band of operation.Here I suggest to to do a spectrum sweep test in around the C-band reciver and at the WiMax BS to know the intensity of Interferance, then from the results findout the specifications of dB suppressions for the Low bandpass filter required at Wimax Base Station,pass on the specifications to the local vendor in your region.They will design as per your requirement.
Do let me know if any further guidance required.
Sandeep
[e-mail]

[Simon]

Amitabh,

Thanks for the feedback. Frequency in use is 3.6 - 3.7Ghz. Is there a Wimax band reject filter for 3.4 -4.2Ghz?

[Amitabh Kumar]

Interference from WiMAX sytems is very common. The frequency of WiMAX is not given.
There are two solutions
- Use a WiMAX ban reject filter if the WiMAX is in a different band ( see http://www.rfglobalnet.com/product.mvc/SKY33108-360LFWi-Fi-PassWiMAX-Reject-Filter-0001?VNETCOOKIE=NO

- Use a wiremesh shield around the antenna,giving the antenna only look towards the satellite

- use a 3.8 M antenna, these have better directivity