Need some help - 8 foot Unimesh install

How does 5G interference manifest on C-band? We have locked quite a few feeds on 101, but they all have complete periodic drop-out's. We'll go from 15.0 dB C/N to 0 then back.

Or does this seem more like a reception issue?
You are accurately describing interference. The target signal will lock, decode and continue to play until excessive reception errors can no longer be corrected. The signal lock is lost until enough data is received to lock and decode. Repeat... repeat... repeat...
 
How are you moving the dish across the arc between satellites? Are you driving the dish East / West with the motor or rotating the entire mount on the post?

Which LNBF are you using? With the mount parked at the top of the arc, is the "0" skew stamp aligned with 12 / 6 o'clock or 3 / 9 o'clock?
 
How are you moving the dish across the arc between satellites? Are you driving the dish East / West with the motor or rotating the entire mount on the post?

Which LNBF are you using? With the mount parked at the top of the arc, is the "0" skew stamp aligned with 12 / 6 o'clock or 3 / 9 o'clock?

We are moving it with the actuator.

This is the LNB currently in use:

 
Excellent! Thank you for clarifying that the actuator is moving the dish.

For proper polarity reference, align the C138 "0" skew stamp with 3/9 o'clock with the dish parked at the apex of the mount. With the dish still parked at the apex, locate and identify either the 107w or 105W satellite. This will be the approximate center and maximum elevation of the arc, providing a starting reference for visualizing the location of other satellites.
 
  • Like
Reactions: comfortably_numb
If you have a Spectrum Analyzer (even something as simple as a TinySA Ultra) you would see exactly what satellite and terrestrial signals are present and identify potential sources and direction of interference (and locating satellite carriers that may not be blind scanning).

With that said, most suburban ares of the US and Canada now are transmitting both 5G N77 Low Band range (up to 3800 MHz) AND N77 High Band range (up to 3980 MHz). The C138 is very effective at attenuating N77 Low Band range (Red Filter).

If N77 High Band is used by a cellular provider in your area, these higher frequency signals will not be attenuated by the C138. N77 High band signals fall within the C138/C238 LNBF's 3800 - 4200 MHZ band pass and will interfere with satellite signals in this entire block conversion frequency range. To effectively filter N77 High Band interference, use the C140/C240 (Blue Filter). The narrower band pass of 4000 - 4200 will allow satellite frequencies to pass in this range and attenuate signals below 4000 MHz (preventing the unwanted signals from overloading the entire frequency block).
 
I remember how telco transmission interference manifested
Yes, analog telco interference was easy to identify and locate. How many BUDs did we install behind barns and houses to block the telco PTP interference? :)

Digital signals with the forward error correction creates a digital cliff with the digital receivers. Everything can look and sound perfect.... until.... the signal errors become to great and then no signal lock or decode. Then we return to our "Old Schools Tools" to identify and analyze the analog carrier carrying the digital transport stream.
 
  • Like
Reactions: comfortably_numb
How does 5G interference manifest on C-band? We have locked quite a few feeds on 101, but they all have complete periodic drop-out's. We'll go from 15.0 dB C/N to 0 then back.

Or does this seem more like a reception issue?
comfortably_numb,

That occasional drop out is either caused by a tree branch, blowing in the wind blocking the signal or 5g interference.
I speak from personal experience with both.

John
 
  • Like
Reactions: comfortably_numb
Well guys, so far we've got satellites tuned in from 97-105 and locking 95% of what's available. New LNB is ordered to see if it will help reduce the 5G interference.

I'm continuing to scan in satellites.

IMG_8201.jpeg
 
Last edited:

USALS Motors: The Device from Hell

Top