How To Look For & Find 5G Interference in C Band

[ArloG]

Haven't managed to setup a 5g 'wardriver' yet. Looks like T-Mobile setup 5G service in a few towers here recently. Fortunately they are off axis and behind my dish miles away and not in LOS of it.
So far in youse guys (lol) experimentation. Does it appear as if major interference is only in a situation where the dish is a few degrees of LOS of a tower?
Or is it possible interference may be possible from side lobes also?
I had some heavy thinking remembering my analog cell phone and pager days where we worked in screen rooms.
When the door closed. All external RF was as close as possible 100% attenuated.
Since my assumption at the moment is that 5G is of a frequency high enough to give a narrow beam. As EB stated.
I'm wondering if a frame of some size. Maybe not too big. With metal window screen on both sides and earth grounded. In between the dish and tower.
If that wouldn't attenuate interference at all. Just a concept.

Brian is a real good dude. I would never treat him as a Best Buy or wally world. Can't blame him at all for the no return statement. I mean, if an lnbf was borked out of box. Hopefully he would oblige.

[el bandido]

T-Mobile Home Internet and T-Mobile cellular services have only a small amount of frequencies in the 3.5 - 4 GHz range. You probably don't need to worry about T-Mobile unless you are in a highly populated, Urban area. Verizon and ATT can operate somewhere in the 3.5 to 4 GHz on almost every cell tower in the United States. The cellular services in the 3.5 - 4 GHz range will not effect your c band satellite dish unless enough unwanted signal collects on the dish and overloads the lnb. It's that simple.

Studies on cell tower interference in c band are usually within 300 meters of the tower. In other words, your satellite dish needs to be within 300 meters of the cell tower if you want to have a decent chance of interference from the cell tower. Studies are studies, but a distance of 300 meters from the cell tower seems reasonable when you think about it, Satellite dishes point up, towards the sky and are very directional.

Some wildcards for c band satellite interference are micro or mini-cells, Internet gateways connected to c band frequencies, and possibly cell phones operating on c band frequencies. Instructions for cellular Internet gateways suggest installing the gate near a window. So it is easy to see Internet gateways interfering with c band satellite dishes in crowded neighborhoods.

What to do or what to put up will depend on where the interference is coming from and how strong it is. Hardly any two interference situations will be the exact same. Surely it would be possible to put up large mesh panels and block part if not all of the interference, but what would the yard look like afterwards? Most c band hobbyists will need to move - relocate the dish or install filters if they are experiencing in-band interference.

[armadillo_115]

Arlo, I have not had any 5G interference to deal with yet, so I couldn't say. Hope I never do!

I always had glitches between my two bud systems using lnbf's. Switching to dual lnb feedhorns (as EB suggested) was the only cure I found for it. I hope to never go back to lnbf's... BUT... I would hate to buy 4 wave guides and/or 4 new 5G blocking lnb's Ouch! Of course if every needed in the future, the cost of wave guides and 5G blocking lnb's may be less in the future.

Also: Wife would lose several lower freq channels she likes on the Atlantic sats.

My distance from the main road and protection from hills/trees may prevent any towers from bothering me. A neighbors cell phone or home internet device would be the most likely culprit here.

[el bandido]

If you are surrounded by trees instead of buildings, and your nearest neighbor is 500 feet or more away, then you probably will not have any cellular c band problems.

A 3.5- 4 GHz frequency is going to act like a shotgun. When you are close to the transmitting source, you will get the full effect of the signal. The 3.5 - 4 GHz frequency will scatter fast as you move away from it. Obstructions like trees and hills will speed up the signal scatter at these frequencies.

A yagi or highly directional beam type antenna will usually be recommended when you have direct, unobstructed view to a cell tower, and are trying to increase the signal from it. A panel type antenna will usually be recommended when you have trees or other instructions in front of a cell tower, and are trying to increase the signal from it. The reasoning for this is simple: A yagi has a tighter beam and is more directional. A panel antenna has a much wider beam as compared to a yagi and could be more useful for collecting a scattered signal.

When dealing with interference, you have to know where the interfering signal is coming from and at least have some idea of how strong it is. This is the first step if you want to have success.

[ArloG]

I'm good for a long time. 300m is a good enough figure to know I'll probably never get any interference. Towers are N and NE of me and even though I can see the beacon lights at night of the due north towers, they are at least 5 miles away. Whatever that works out in km is up to ya'll.
Hey man. Who wouldn't want a big fly swatter in their yard? Heh! There is this guy here that had a bed spring on pulleys in a tree who hoisted it up and down to to get the Bills game. That blew me away. And....it actually seemed to work even with a deep fringe antenna on his house. Go figure.

I've made patch antennas for L band Inmarsat.
The REC put in fiber. I still have cable. Subbed to 100mbps service and recently found out they upped it to 200mbps for the same price. Pretty cool. Fiber is 5 bucks more a month.
What's cool is I built a 2.4 GHz 14 element yagi and put DD-WRT on a Netgear R7000 router. Running it in client bridge mode.
My "neighbor" (I live in the stixx) is about 3/4km away from me through trees. I house watch for him in the winter when they hit Fl.
Pretty good signal and it's bridged to my LAN.

The big worry was potential lobe interference on my dish. So 300m settles my mind. Still a bit amazed that Othernet can use a bare ku lnbf pointed at a satellite w/o a dish and get signal.
So the bare C band lnbf for a "rifle scope" to hunt out 5G spectrum was a thought.

Finding and getting a quality orthomode and a couple of Norsats has crossed my mind. Its just that from all of the reading here and there. The wow factor don't justify it. But....does it guys?
I mean. There's "Corvette Joe" here. A Belgian dude. He's had Ferarris, Porsche's. Has a photo of him and Enzo with arms around each other's shoulders.
He was at the local body shop getting his CTS from some stone chip repair. Not actually bragging. "Adamant". Of how fast his cars were.
The body shop owner muttered about a car in the lot that would blow them all away. Mind you that was before Hellcats came out.
Joe looked and asked where?? The shop owner told him the silver 4 door. Joe went out and made a couple of circles around it. Kind of "meh". We talked. I popped the hood. He checked things out.
Rocky (shop owner) said "Give him a rip". I asked him if he wanted. So Joe got in. Headed out to the edge of town. Just enough RPM's and boost to make him thing "That's it?!!!"
Hit an open stretch and opened it up after switching to the track map with the trik cruise control button mod.
All he did was stiffen up and eye locked the tach and speedo. Holyshitholyshitholyshitholyshit. That's all he said. And had Tourette's on and off for the next 15 minutes after we got back to the shop.
Haha. Not bragging. It is what it is. But...

Will I get similar reaction with an ortho/Norsat setup on my 12 footer (you do the metric convershion)? Would a Corotor do the same? I have a box of them. They need a teardown and bead blasted and powder coated.

[el bandido]

Walking around the yard while using a c band lnb for an antenna would be a messy experience at best. I think you would be better off using a small yagi that is designed to operate on c band instead. Try it and see.

As for changing lnbs, you usually get what you pay for. New Japan Radio (NJR), and Norsat are two common brands that you will see at commercial satellite sites. But if you don't know WHY you are changing lnbs, then you probably shouldn't.

[el bandido]

The reason it is possible for Othernet users to get a signal without using a dish is the signal strength that is needed.
Here is a quote from the Dreamcatcher user manual for Othernet:

Lower Rssi levels such as -100 dBm may carry signal, but the
Dreamcatcher is not sensitive enough below -95 dBm

Usually a fta receiver will have tuner specs between -30dbm and -60dbm. Othernet Dreamcatcher is looking for a signal value between -60dbm and -95 dBm. So Othernet can operate using a signal that is 1000 times weaker than what a fta receiver needs as a minimum requirement. Ditto the amount of information being sent and the Othernet frequency width.


I also notice the Edision MIO+ doesn't play or has trouble playing channels when the TinySA Ultra shows the transponder signal at or around -60dbm. Every frequency I have been able to check and verify on the TinySA Ultra seem to be where they are supposed to be. Satellite beacon frequencies displayed on the TinySa Ultra are almost identical to what is advertised.

[ArloG]

It goes back to the VU+ guy with 'roll your own' tuners. He's getting channels and tp's that the mio is blind to.
My weak mind is saying what if a receiver with a hot tuner combined with sensitive lnb's were used.

'dillo mentioned in #54 of troubles. Assuming he went to an orthomode setup fixed the glitches he experienced. Wondering what the glitches actually were.
Mine is a C2-W. One output of it went weak. Perhaps because the F connectors were loose from factory. I don't know. Haven't cracked it open to check. Sometimes the center connector turns inside the teflon independent of the outer fitting. That's a good thing. Sometimes not. Stressing the connection to whatever it's soldered to.

Makes total sense now Othernet working with low dB levels. It just never occurred that an lna/lnb could even work at all w/o a 'mirror' to concentrate signal at the throat.
Low signal, low data rates, and good error correction seems to work well on the Dreamcatcher. When it was Outernet all of the signal processing was done in software.

Making and tweaking the 2.4 GHz yagi took a bit of doing. Up that a gig in freq. and who knows. Even with 12 elements for directors I see frontal lobes several degrees from center.
Here I used telescoping brass hobby tubing and a fiberglass driveway marker rod. Starting with a dipole for the active element and tuning to length with the trusty HP network analyzer.
Switched to a folded dipole and loop match. Worked much better and more stable. Wow. 4 GHz might be a bit of a challenge. You just look at it and SWR/return loss is all over the place.
So maybe an all in one, factory tweaked lnbf really doesn't sound that far-fetched. Strap a couple of 9V's in series and a DC block.
I'm steering towards a lower amplified working freq. and feeding an SDR. Lets see.
Projects!

[el bandido]

Vu+ produced great subscription boxes. Vu+ satellite receivers do not perform exceptionally well as a fta receiver. But if you think they are that great, then buy one or two. Also, the pluggable tuner thingy is Wonderful! That is until you turn on the receiver and find the tuner is not recognized. Then the pluggable tuners are not Wonderful anymore. But again, buy one and see for yourself. Great subscription box!

Usually making a home-made antenna costs more than what you could buy the antenna for. Problem is, you don't learn much buying an antenna pre-made. Good job with the homemade antenna!


The strongest 2-3 GHz signal I could find around here with the TinySA was between -20dbm and -30 dbm. The signals came from a wireless router and cellphone. Both items were a few feet from the TinySA when these measurements were recorded.

My satellite noise floor seems to run around -70dbm. The documentation I have read says that reducing an unwanted signal to -55dbm will probably take care of any interference issue. So if I had a -30dbm unwanted signal that was interfering with c band, a filter of -25 db would take it down to -55dbm. A 45db filter would take the unwanted signal down to -75dbm. Providing of course the filters worked in the same frequency range as the unwanted signal. This is one way to use the TinySA analyzer to determine what you need to solve interference issues.

[armadillo_115]

...'dillo mentioned in #54 of troubles. Assuming he went to an orthomode setup fixed the glitches he experienced. Wondering what the glitches actually were...

Arlo, It was a long running mini-series over at Hyper's old site. I have TWO 10ft buds feeding 3 - 4 receivers. (Receiver #'s vary at times) Was running a dual lnbf on each bud. Had voltage (?) interaction between receivers. Wherever we would change channels on one receiver it would often glitch the other receivers. (Especially when receivers were using opposite buds) Either had to wait for signals to stabilize or reboot the receivers. Tried different: lnbf's, diseqce switches, multi-switches, etc.

The only cure was running dual feed horns with lnb's instead of lnbf's.

I can't say I got any real signal increase running the dual feed horns. If anything, mine are slightly inferior on many transponders. I'm sure it would be better if I wasn't running bargain basement lnb's.

Money can't buy the peace and quiet those dual feed horns finally brought me. lmao