Still Fighting Intermittent Interference

[Bassplayer 1964]

I have been having this problem for probably close to 5 years now on and off. I ordered the C140 Titanium LNB and have it installed now but I'm still having the trouble as much as before, strangely. Odd thing is it only affects 4180 H on 101 W other carriers are fine, and even stranger when it's really showing up on my Os Mio it plays perfectly on my V8 meter! Some boxes act up worse than others it seems. I have no 5G service here at all yet but there's construction starting straight across from me on the ridge in a few weeks. It will be a Us cellular tower. So my days of TV are numbered because no OTA can be had here There is a tower to the SE side of my dish, maybe 5 miles away that may have 5G on it now and it's US Cellular as well. Any ideas?

 

[Titanium]

I have been having this problem for probably close to 5 years now on and off. I ordered the C140 Titanium LNB and have it installed now but I'm still having the trouble as much as before, strangely. Odd thing is it only affects 4180 H on 101 W other carriers are fine, and even stranger when it's really showing up on my Os Mio it plays perfectly on my V8 meter! Some boxes act up worse than others it seems. I have no 5G service here at all yet but there's construction starting straight across from me on the ridge in a few weeks. It will be a Us cellular tower. So my days of TV are numbered because no OTA can be had here There is a tower to the SE side of my dish, maybe 5 miles away that may have 5G on it now and it's US Cellular as well. Any ideas?View attachment 187374View attachment 187372

What is the OSMio SNR (CNR) reading on 4180 TP when it decodes? What is the SNR (CNR) when it does not decode? Same questions for the V8 meter. One receiver may deal with marginal signal decoding better than another.

My guess is that the SNR is marginal for the FEC and a fix might be as simple as scalar placement (FD ratio) with attenuating adjacent satellite interference or even an adjust skew for an optimized X-Pol isolation.

A spectrum analyzer would provide better data than my guessing. Are you observing any interfering terrestrial carriers within or below 3890 MHz.

To my knowledge, US Cellular does not hold N77 High Band licenses, only N77 Low Band.

 

[Bassplayer 1964]

What is the OSMio SNR (CNR) reading on 4180 TP when it decodes? What is the SNR (CNR) when it does not decode? Same questions for the V8 meter. One receiver may deal with marginal signal decoding better than another.

My guess is that the SNR is marginal for the FEC and a fix might be as simple as scalar placement (FD ratio) with attenuating adjacent satellite interference or even an adjust skew for an optimized X-Pol isolation.

A spectrum analyzer would provide better data than my guessing. Are you observing any interfering terrestrial carriers within or below 3890 MHz.

To my knowledge, US Cellular does not hold N77 High Band licenses, only N77 Low Band.

I haven't caught anything yet on the spectrum analyzer but then again the problem is intermittent enough it's hard for me to get setup in time. I have noticed today CNR was 10db when it was working normally and varied only down to 9 when the problem was happening. I noticed my quality reading has dropped to 64% this week from a way higher reading before but the problem was still present. I just don't think it is 5G bothering me that bad from 5 miles away shielded by another ridge and using a filtered LNB. I don't think any other carriers are on that tower but I don't know anyone with US cellular to find out for certain. I will setup to catch the problem on my SA and see if I detect any spikes from anything near the lband frequency. A recheck of my scalar centering may be in order since it does seem a bit worse than previously. Especially given it's a prime focus dish. Thanks for your suggestions! I will gather some additional data and report back

 

[Bassplayer 1964]

A small update on things. I checked the signal parameters tonight when things were working good and found C/N on 4180 to be 10.39Db and fluctuating slightly but never out of the 10 db range. Meter is showing signal level at 72 and quality also at 72. In my thinking that is approaching too low to be reliable. A quick question on scalar alignment with the Titanium LNB. How is the best way to verify its centered on the support arms after I verify the FD is correct? If all is straight on the arms shimming may be required but hopefully not. I've thought about a cork or similar item I can fit in the scalar and a laser pointer centered in that item to make sure it's hitting true center of the dish but it may be hard to find a good fit for the scalar's lnb location. Thanks

wt

 

[primestar31]

A small update on things. I checked the signal parameters tonight when things were working good and found C/N on 4180 to be 10.39Db and fluctuating slightly but never out of the 10 db range. Meter is showing signal level at 72 and quality also at 72. In my thinking that is approaching too low to be reliable. A quick question on scalar alignment with the Titanium LNB. How is the best way to verify its centered on the support arms after I verify the FD is correct? If all is straight on the arms shimming may be required but hopefully not. I've thought about a cork or similar item I can fit in the scalar and a laser pointer centered in that item to make sure it's hitting true center of the dish but it may be hard to find a good fit for the scalar's lnb location. Thanks

wt

I use a 12" laser level clamped on the scalar so the laser beam is exactly in the center of the hole. Then you make any adjustments so that the beam beams to the dead center of the bowl of the dish itself.

And/Or: simply use a tape measure at 4 points around the scalar, and measure to the edge of the dish. Once ALL 4 points measure exactly the same, it's centered and equal.