Titanium C138 and C1PLL spectrum graphs and 5G

[primestar31]

Yes. The signal graphs are about as close as I can get to a spectrum analyzer in post #1 and post #17. They show narrow spikes below 3800 MHz. When I put EBS Pro into continuous scan mode I could see that the spikes randomly appeared and disappeared. So they are not from an FTA satellite (those are somewhat constant). And its not radar because the frequency of the spikes vary. (Which is because 5G has many channels).

Also, the interference has been gradually getting worse in the 3 months I have had the C138. And I got a postcard in the mail from Verizon advertising that 5G internet is now available in my area.

Its not just 5G from cell towers in my area. When someone in my neighborhood installs 5G internet they become a new source of interference.

Earlier in this thread, Titanium suggested that I get my neighbor to install an app to identify the tower. But that would not tell me which houses have 5G home internet. Even if I knew there is nothing I could do about it.

Finally, please take another look at those spectrum graphs. It looks to me like the C138 is not doing very much to attenuate signals in the 3700-3800 range. That's my opinion, others may disagree. Maybe it needs a stronger filter?

Perhaps you can work with Brian as a test site, to tweak the 5g rejection on his lnbf? I wonder if maybe you got one that's defective, meaning not working as well as it should work? I wonder if the providers in your local area have the transmitters cranked up illegally too high? I don't know, I'd have to say only Brian could tell us what's up with your spectrum prints. Titanium

I just had another thought, do you have a local airport or something, where you can talk to somebody there and ask them IF they also are suddenly experiencing high levels of 5g ingress? If so, ask them what they are doing to fix it.

 

[N6BY]

Perhaps you can work with Brian as a test site, to tweak the 5g rejection on his lnbf? I wonder if maybe you got one that's defective, meaning not working as well as it should work? I wonder if the providers in your local area have the transmitters cranked up illegally too high? I don't know, I'd have to say only Brian could tell us what's up with your spectrum prints. Titanium

I just had another thought, do you have a local airport or something, where you can talk to somebody there and ask them IF they also are suddenly experiencing high levels of 5g ingress? If so, ask them what they are doing to fix it.

I don't have any airports nearby.

I am currently getting NASA OK now, which is the strongest transponder at 16.5 - 17.0 dB here. Also with that high of signal quality I am pretty sure my dish is lined up as good as it can be with 127W. But some of the other transponders on the same satellite have pixelation.

I just checked Verizon's website and now they contradict what they said earlier (in post #1) about 5G Home Internet being available in my area. Now when I type in my address it says "Not available". But when I look at their 5G coverage map it shows my house clearly in the coverage area. They even sent me a postcard advertising the service. Perhaps my area is maxed out right now and they are turning down new activations? Another mystery.

 

[Titanium]

The amplitude of the local interfence may require more attenuation than an on-board bandpass filter provides. You may need to use tuned cavity filers installed in-line with the waveguide using a traditional feedhorn/LNB configuration to provide greater out-of-bandpass attenuation. Tuned cavity filtering is expensive and likely out of budget for many hobbyists.

There is no golden bullet that addresses all RFI. Identify the source, frequency and amplitude of the interference. Determine the attenuation required to reduce the interference to the point where the FEC can function.

For most hobbyist, an inexpensive LNBF PCB bandpass filter will provide the required attenuation. Others, with high levels of interference may require greater attenuation provided by physical barriers and/or hardware cavity filters.

Also, remember that we are entering another C-band frequency range transition next year, which may require installing new tighter bandpass filter solutions. As a hobbyist, I would be hesitant to purchase an expensive 5G cavity filter with 3800-4200 bandpass, knowing that next year a new cavity filter (4000-4200 BPF) may be required.

 

[N6BY]

The amplitude of the local interfence may require more attenuation than an on-board bandpass filter provides. You may need to use tuned cavity filers installed in-line with the waveguide using a traditional feedhorn/LNB configuration to provide greater out-of-bandpass attenuation. Tuned cavity filtering is expensive and likely out of budget for many hobbyists.

There is no golden bullet that addresses all RFI. Identify the source, frequency and amplitude of the interference. Determine the attenuation required to reduce the interference to the point where the FEC can function.

For most hobbyist, an inexpensive LNBF PCB bandpass filter will provide the required attenuation. Others, with high levels of interference may require greater attenuation provided by physical barriers and/or hardware cavity filters.

Also, remember that we are entering another C-band frequency range transition next year, which may require installing new tighter bandpass filter solutions. As a hobbyist, I would be hesitant to purchase an expensive 5G cavity filter with 3800-4200 bandpass, knowing that next year a new cavity filter (4000-4200 BPF) may be required.

I live is a small valley surrounded on almost all sides by homes along the ridge, any one of which could be a source of 5G interference. Also, I spotted what I think is a 5G small cell site on top of a street light about 100 yards away. So my dish is probably getting 5G from all directions. Without some expensive diagnostic equipment it would be difficult to determine exactly which direction(s) the 5G is coming from.

The best diagnostic I have are the spectrum scans from EBS Pro.

And you are right -- I cannot afford a cavity filter.

The question I have is: Is it possible that the mfr. mistakenly made mine with a pass band of 3700-4200 MHz? (instead of 3800-4200). The EBS Pro spectrum graph with the C138 installed shows strong 5G and even some satellite transponders in the 3760 MHz vicinity.

 

[Titanium]

Your previous testing has shown that the C138 (3800-4200 BPF) is attenuating the 3700 range. The C1PLL LNBF (3700- 4200MHz BPF) was not filtering the 3700 range. You were previously receiving programming on the C138 that was not received on the C1PLL. If both were the same 3700-4200 bandpass, this would not be the case. The bandpass range is fixed and cannot shift as it is attenuated by pin cushion filtering traces on the PCB.

One might need to do extensive testing to determine which signal is overloading either the IF conversion or mix process in the receiver. It is not as simple as picking the strongest carrier and saying that it is the definitive source. I would guess that it is close to the bandpass range and it might be a harmonic landing within the bandpass.

Measure the suspect carrier on the C1PLL. What is the peak amplitude reading? Measure the 3760 carrier on the C138. What is the peak amplitude reading? Compare the results of the two tests. The signal will be attenuated, but by how much? My guessimate at 3760MHz would be -30dB+ range.

Is this attenuation adequate for decoding? Many system and link budget variables: FEC, reflector/feed efficiency, distribution losses, receiver performance.

Build a 4000MHz cantenna or use a bare LNBF with attenuation pads to sniff the 3400-3800 range. Effective to "Fox Hunt" the signal sources. Like many other hobbies.... location, location, location.

Btw... you should join our monthly Sierra Foothills ARC Fox Hunts. Last Saturday of the month after our Breakfast at Mel's Diner in Auburn, CA.

 

[N6BY]

I see your point and I agree that I probably did not get the 3700-4200 version of the LNBF by mistake.

"Measure the suspect carrier on the C1PLL. What is the peak amplitude reading? Measure the 3760 carrier on the C138. What is the peak amplitude reading? Compare the results of the two tests. The signal will be attenuated, but by how much? My guessimate at 3760MHz would be -30dB+ range".

In post #1 the graphs show this. The 3750 red peak with the C1PLL is about -34 dB and the C138 3750 peak is about -46 dB (I am not counting the transient 5G spike in the C138 graph). So it looks like I am seeing only about a 12 dB attenuation at 3750 MHz.

But I am still getting NASA TV on 127W and that's what I watch the most.

As for 5G fox hunting, I lack a portable receiver or spectrum analyzer that goes up to 4 GHz. The best I could do would be to get a 5G cell phone and look at the signal bars, but SWMBO says no to that idea. Also, I don't think a cell phone would 'see' 5G home internet radios?

 

[mememeth]

get the new “ tiny sa ultra “ spectrum analyzer, @ aprox $119+ ship from “r and d electronics” maybe bo but put order in, they are selling fast, , brian may want to comment, . it will go to 12 gig,

 

[Titanium]

Read about the release of the TinySA Ultra, but have not tried one out. Not sure about the ultra disabling of the bandpass to achieve higher frequency coverage. Might be fine for low RF environments, but that is only a guess.

 

[N6BY]

It looks like an interesting device to play with, but the high frequency mode has some limitations.

I'm OK for now with NASA TV still receivable along with some other channels.

... One strange thing I've noticed is that if my OS Mio+ 4K detects even the slightest error it wont blind scan a transponder and add its channels. For a while I could not get NASA TV to scan into the channel list. But once it scans in it stays in and I see no glitches or pixelation with it. So I won't blind scan any C Band satellites anymore. If I do I will get a random number of transponders with each scan.

What bothers me the most is that 5G is interfering outside of its assigned frequency limits. I guess that's because its so powerful compared to satellite signals that it overloads the receiver.

 

[primestar31]

5G is interfering outside of its assigned frequency limits

That's NOT supposed to happen in any frequency band. Perhaps you need to contact the FCC, and report this. They might come out and check it for you, and IF the cell providers are pulling some monkey business by cranking up their signals levels too high, they'll set them straight.