Good evening everyone,
I love tech. And I think it's really cool and love the speed of 5G
technology. Of the three types of 5G, the "mid band" 5G gets you 300 mb/sec
to 1 gb/sec speeds. How great is that?
Unless, of course, it interferes with your satellite signal. And here at
AllisonHouse, we know about that all too well.
When a telecom turned on their 5G on towers close to our NOAAport receiver
dish one fine Saturday morning, I saw that we were not getting any data
(and was blasted out of bed from our alerting system to kindly let me know
that, LOL!). Sure enough, we had a signal, but the carrier-to-noise (CN)
was really low, well below what was needed to decode packets. I pretty much
knew what that was about. Thankfully, our system instantly switched to a
backup feed automatically, so we didn't lose any data. I talked to our
engineer, and he immediately knew it was 5G interference from a 5G provider
causing the issue. We ordered the 5G filter that the National Weather
Service uses (with a very minor model difference that didn't change any of
the specs) to solve the problem; that filter knocks that interference down
by 30 dB, which is a lot! We got the filter installed, and we were back to
having data, although we were losing more packets than we had before the 5G
was turned on.
Then came the NOAAport satellite move from Galaxy 28 to 31. We repointed
the dish, and got a signal. It was a video signal that we had locked onto
on an adjacent satellite at 121 degrees west. Oops. Then we tried to adjust
the polarity, but after weeks of equipment failures, repoints and
adjustments, we just couldn't lock a signal. We were told to go to a second
engineer who could solve almost any issue. He tried and tried, and we still
couldn't get a signal to lock. Finally, it did lock, but only
intermittently, and still, no data. And when we saw the scope, we knew what
it was. 5G interference! But how?
Well, the frustrated engineer had the lights and bells come on in his head.
The 5G filter we were using was foreign to him, but then he realized it had
the specs of another brand that he saw was causing TV and radio stations he
services to have the same issues. So, he told us we needed to swap our 5G
filter with a much better one: the Alga Microwave C-band 5G filter (blue).
Instead of having a 30 dB rejection spec, this one has 70 dB+ rejection
from 3900 MHZ and below, and at least 25 dB from 4200 MHZ and above. It was
the frequencies below 3900 that were killing us, so the extra 40+ dB of
rejection was needed.
So, this past weekend, the new filter was put on. Bam! What we had locked
on to was indeed NOAAport, and without peaking the signal, data immediately
started coming in. The engineer peaked the dish, and then precisely
adjusted the polarity on the LNB. This latter step is absolutely critical,
because a video broadcast could be coming on the opposite polarity on the
same frequency of NOAAport! In fact, a test video broadcast on the opposite
polarity and same frequency was performed last Friday night, and no issues
were noted on some of the other dishes I monitor. In any case, with a 3.7
meter dish, we get a signal of roughly -26 dBm at the dish, and -33 dBm at
our receiver, with a C/N of 16 on average on a clear day, just a touch
lower when it's cloudy. This is lower than I want, since the NWS C/N
standard is 17 dB, but we still have roughly 5-6 dB of signal "pad " for
clouds and precipitation before we lose data. We should stay up unless
rainfall rates in the path of the signal reach about 2" per hour.
So, now we are back to our winning ways. We do lose a few packets here and
there due to HVAC turning on and off every day at our location, but the
losses are around 200 packets/day total from the 5G and RF nightmare our
dish is located in...surrounded by towers pounding out the 300 mb/sec
goodness, as well as 100,000 watt FM radio and 1 megawatt TV stations. And
let me make one thing perfectly clear: I'm not mad at the telecoms at all
about our troubles, speaking strictly for myself. Rather, I'm really not
happy that the FCC allowed the cellular companies to intrude on the C-band
signals in the first place. But, that ship has long sailed, so we just have
to deal with it.
I wrote this in the hopes that this could be helpful for someone. I know
there are NOAAport 5G nightmares still going on with this, and more to come
as telecoms build out their networks over the next 5 years.
Gilbert
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Opinions are not of my employer, but all facts are.
Gilbert Sebenste
Consulting Meteorologist
AllisonHouse, LLC
