Interference on 72.7, TP 18 only. SNR fluctuates and video pixelates intermittently.

[explorerst4x4@]

Been working on an issue with a couple of channels that reside on 72.7, Transponder 18. We have three Smartboxes at a site, with DishPro LNBs, that consistently see CER (codeword error rates) only on this transponder. I have changed out the power inserter, LNB, connectors and cable. The dishes have been peaked as well. The closest transponders with working channels are at Transponders 15 and 23, not experiencing any issues.
I have observed this behavior on the signal meter directly off the LNB, which shows as the SNR fluctuating rapidly and video pixelating. Signal is at -28.6 dBm, with an SNR of 74, 10 feet from the LNB.
I don't have a lot of experience with Dishnetwork or DirecTv equipment or signal.

72.7 TP 18 is 1878 Mghz. PCS cell phone service is the only thing I am finding that would interfere with this frequency. How close does a tower need to be to be a problem? Any thoughts or questions are greatly appreciated.

 

[TheKrell]

72.7 TP 18 is 1878 Mghz. PCS cell phone service is the only thing I am finding that would interfere with this frequency. How close does a tower need to be to be a problem? Any thoughts or questions are greatly appreciated.

That is a difficult problem. Just thinking about the physics of this situation, if your satellite antenna had infinite rejection of off-axis signals, then you would get zero interference from cell phone towers which are presumably far away from the satellite antenna LOS. But since no such thing as "infinite rejection" is possible, we have to make assumptions and guess. Are you able to erect a shield between the satellite antenna and the nearest cell phone tower? If the cell phone tower is somewhere behind the dish (which is it's own shield), then you need only shadow the LNB assembly. If the tower is instead behind the LNB, then you would need to shield the entire dish. Likewise, look at any other radio-reflective surfaces that might be bouncing cell phone signals back into the LNB. Note that this is just my wag about what might be happening.

 

[HipKat]

Interesting. I was just on a commercial job with 15 211's using analogue modulators to supply feeds to TV and Treadmills, etc at a Health Club and one channel, in particular, has 60 Mhz modulation interference that I nor the old-timer that came out with me could figure out. Signal/dbm's was stellar, but I didn't check individual transponders

 

[explorerst4x4@]

Are you referring to 60 cycle hum on an analog modulated channel?

 

[HipKat]

Are you referring to 60 cycle hum on an analog modulated channel?

Yeah!! . Sorry for the terminology fail

 

[Jim5506]

That just keeps everyone in the same key.