5g interference

[Titanium]

I guess the C140 was a waste of money. Looks like I won't be watching much C-band anymore.

Might not even be 5G interference. What is the CNR on 4032V15201 on 117W when it is decoding reliably? As it is DVB-S 5/6, should decode reliably to approx. 6.5dB C/N. If your CNR doesn't have adequate headroom above 6.5 dB (minimum recommended C/N), other minimal factors may be affecting the reception.

5G interference is usually exhibited as fluctuation of lock/unlock (steady video and sound then microblocking and stuttering audio repeating cycle) as the Forward Error Correction (FEC) attempts to gather enough uncorrupted bits to correct the errors and begin decoding again. I wouldn't expect the CNR just to drop to 0dB and remain.

Try shifting the TP frequency to the published 4031 MHz +/- 1, 2 or 3 MHz. This frequency is very close to the filter bandpass, so the C140 attenuation slope is typically 25db and ramping up near the filter edge.

If this is the result of 5G interference, you might need a tighter filter such as an inline mechanical waveguide on a feedhorn in addition to an 4000-4200 MHz BPF LNB and maybe even build a RF fence to block the source.

 

[WhiteBeard]

Might not even be 5G interference. What is the CNR on 4032V15201 on 117W when it is decoding reliably? As it is DVB-S 5/6, should decode reliably to approx. 6.5dB C/N. If your CNR doesn't have adequate headroom above 6.5 dB (minimum recommended C/N), other minimal factors may be affecting the reception.

15.1 dB with occasional drops to 0 and back to 15.1 dB

5G interference is usually exhibited as fluctuation of lock/unlock (steady video and sound then microblocking and stuttering audio repeating cycle) as the Forward Error Correction (FEC) attempts to gather enough uncorrupted bits to correct the errors and begin decoding again. I wouldn't expect the CNR just to drop to 0dB and remain.

Try shifting the TP frequency to the published 4031 MHz +/- 1, 2 or 3 MHz. This frequency is very close to the filter bandpass, so the C140 attenuation slope is typically 25db and ramping up near the filter edge.

I tried higher freq transponders on this sat with same results. I have this issue on other sats (99, 101, 103) also.

If this is the result of 5G interference, you might need a tighter filter such as an inline mechanical waveguide on a feedhorn in addition to an 4000-4200 MHz BPF LNB and maybe even build a RF fence to block the source.

Don't know if it's worth the expense to change to a LNB/servo or dual output LNB. I have 2 C-band antennas exhibiting this problem.

 

[shopman]

15.1 dB with occasional drops to 0 and back to 15.1 dB

I tried higher freq transponders on this sat with same results. I have this issue on other sats (99, 101, 103) also.

Don't know if it's worth the expense to change to a LNB/servo or dual output LNB. I have 2 C-band antennas exhibiting this problem.

I live practically right next to two 5G towers and when they went live they wiped out everything on C band. I installed the C140 and have watchable signals again with one exception; aircraft radar. I'm in the flight path for two major airports and when the planes turn around over the pacific and head back towards land the radar signals completely overwhelm the LNBF. Watching it on a spectrum analyzer is quite the sight to see. Do you have any radar installations in the vicinity?

 

[WhiteBeard]

I live practically right next to two 5G towers and when they went live they wiped out everything on C band. I installed the C140 and have watchable signals again with one exception; aircraft radar. I'm in the flight path for two major airports and when the planes turn around over the pacific and head back towards land the radar signals completely overwhelm the LNBF. Watching it on a spectrum analyzer is quite the sight to see. Do you have any radar installations in the vicinity?

None that I know of.

 

[arlo]

This was very interesting to find. A NOAA weather station outside of Philly. Aimed most probably at 121W on the NOAAPort tp.
Never really saw a shield on anything but microwave link dishes on towers.
Pretty cool, huh!

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[Titanium]

Looks like a reflector heater enclosure for snow and ice. Note that the enclosure is mounted on the back of the reflector. Warm air is exhausted into the enclosure to heat the dish and prevent build-up of ice and snow on the reflector's surface.

 

[texanboy]

I am using titanium's LNBF (C140), however I am still getting signal drop (Q 75% - to 0%) in some western arc satellites.

What I tried to fix:
1- fine tuned the dish but still not helping. (It is better at night time, but during day, almost impossible to get the images due to pixelation)
2- build an aluminum super feed horn and added around the feed horn w/o success


what else do you all try to get the 5G interference minimized w.o moving the dish?

 

[texanboy]

Update: I just got an aha moment!
There is a nearby airport on my west, possible radar causing severe interference in my western arch satellites.

It is just my gut feeling. maybe I am wrong. I was tweaking around the dish wrapping some aluminum foils around the feed horn for hours, possibly my neighbors thinking me as a crazy person playing around the antenna for hours

Also, pixelation is in the entire 4.0-4.2 GHz spectrum. all TPs has thhe issue. I assume 5G cellular interference is limited to lower end.

Good weekend to you all!

 

[Titanium]

Aviation radio altimeters operate between 4.2 and 4.4GHz. The C140 and C240 LNBFs are designed to filter below 4.2GHz and pass 4.0 to 4.2GHz. We left the top of the bandpass open as the majority of users do have a need for filtering above 4200MHz. Aviation radio altimeter interference only occurs in areas which are in very close proximity to larger regional and international airports (not typically available in smaller facilities).

Your best solution to address both the 5G and the altimeter interference sources is to use a LNB with 4000-4200 band pass and install waveguide mechanical filters, which attenuate below 4000MHz and another to filter above 4200MHz. Not inexpensive, but an option.

You might get away with moving the dish behind a structure (or build a RF blocking hardware cloth wall) to block the low elevation terrestrial based Aviation radio altimeter signals. Reminds me of the early C-band days when long line AT&T microwave caused interference. We would do a sight survey using a trailered BUD and often suggest to the customer that we install the dish behind an outbuilding to shield it from the microwave telephone point to point microwave links.

 

[navychop]

Not inexpensive,

Frightening words.

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