dslreports logo
site
 
    All Forums Hot Topics Gallery
spc

spacer




how-to block ads


Search Topic:
uniqs
1003
share rss forum feed


Balsamea

@99.198.85.x

Surfbeam 2 Modem SNR=7 too low for clear sky?

National Weather Service Data at time of the above modem check.

FEW060=a few clouds at 6K ft.
FEW070=a few clouds at 7K ft.
SCT110=Scattered clouds at 11K ft.

I'm getting significant SNR reductions when there are clouds at all 3 levels and one or more of them is OVC (Overcast), or if it's raining.

During the past five rain events in May and June, SNR always dropped badly (below 4, and as low
as -0.3 ... often loses connection below 5). But I never had this trouble with rain or overcast sky for two years from the installation in Feb 2012 to Apr 2014.

Lately on a clear day (and love is all around me) SNR runs 6.5 to 7.1, occasional dips lower.

During the first year I had connection failures unrelated to weather. Tech Support kept saying it was my router because every time they had me connect by direct wire (bypass the router - Belkin N300) and it worked. But it also worked when I put the router back in place. So that only proved what I knew before I called them ... if I reset the modem once or twice I'll get back online.

So I ran an ethernet cable and eliminated the router. Finally they said there was a problem and needed a tech on site. Dish needed alignment. This was in Jul 2013, 16 months after installation.

Watching the tech is when I first learned how to look at the modem status via browser. (He spent a lot of time just staring at it.) So I never knew the SNR at installation or at any time until the realignment.

When the tech walked out the door SNR was 7. I've monitored it since then, and like I said it runs in the mid-6's. The trouble with rain events started only during the past two months, May-June.

From what I've read in all the forums recently, a typical SNR is north of 8, often 10 and more.

When I lose connection, Support says, "Well, it's raining in your area." They won't commit to a number that would be a "typical" SNR. It doesn't matter to them that I did not have such sensitivity to mere rain or snow for over two years. Actually, I was impressed with it all that time, because I expected weather to have more influence. I'm not impressed any more.

Initially I was on Wildblue, but Dish has been going to Viasat often, switching back and forth (as seen in testmy results). In this latest rain event, they were on Wildblue, Viasat last time, so I don't see a correlation between either provider and the problem. (Are they merged companies?)

Speed is good as long as SNR stays above 5.5. Typically 10-20Mbps DL and 1.5 to 3 UL. You can find a lot of tests under the name Balsamea at testmy.

So ...

What really is a "good" SNR under a clear sky? What is a typical amount of drop in SNR during moderate rain or snow, i.e., normal weather events, not major storms?

How often does rain or snow knock you offline? I'm down 5 for 5 rain events in May and June, which is new to me, after spending loads of time singing online in the rain for over two years.

In t-storms or severe wind conditions I unplug everything, so I don't care where the SNR goes at those times. But I never had trouble during rain activity leading up to a t-storm or after it, until now.

Thanks for any info, advice or guidance. Great forum.

DrStrangLov

join:2012-03-28

said by Balsamea :

SNR....But I never had this trouble with rain or overcast sky for two years from the installation in Feb 2012 to Apr 2014.

Exede 5 and Exede 12 are different...so, for Exede-12, this thread might be instructive.

»SurfBeam 2 - Modem Status (Settings)

What is Tx RF Power when it rains?

DrStrangLov

join:2012-03-28
reply to Balsamea

>But I never had trouble during rain activity leading up to a t-storm or after it, until now.

I don't know if ViaSat's engineers twitched something during less humid conditions, and now that higher levels of humidity are here, stuff happens.

When beaming from the moon to Earth, speeds are very much affected via Earth's atmosphere; hence, ViaSat's signal twitching should be done during the worse weather conditions.


OldSatUser

join:2012-05-10
Fresno, OH
reply to Balsamea

There isn't really a number that defines what a "really good" SNR value is because the SNR value is all relative depending on your geographic location to the beam center. MY SNR on the clearest of clear days never gets higher than say 7.6 or 7.7. It won't get any better than that for me because of my location to the beam's center. Almost always my SNR is the in the 6 range. But others can get a SNR that gets in the 9 to 10 range. It is just the reality of how the system is designed and setup, from the location of the satellite to the position of the beams.

And yes, if the SNR drops too low, you will lose connection.


DrStrangLov

join:2012-03-28

said by OldSatUser:

There isn't really a number that defines what a "really good" SNR value

RE: "But I never had trouble during rain activity leading up to a t-storm or after it, until now...."

Either dish is out of alignment, or ViaSat twitched signal (to accommodate more revenue income).

My Exede-5 beam is "open for business" now, and my uplink is in the toilet these days with light rain. In the toilet means it don't work.


balsamea

join:2013-03-06
Plattsburgh, NY
reply to DrStrangLov

Thanks for the reply.

5 v 12? Is that Mbps? If so, mine would have to be 12. I rarely go below that in clear weather.

I had read that other thread and several others but didn't find anything that quite pinned it down for me.

said by DrStrangLov:

What is Tx RF Power when it rains?

23.8 typically in most of my rain checks, 26.2 in one recent check during rain. Down from 30-32 in clear weather.


balsamea

join:2013-03-06
Plattsburgh, NY
reply to DrStrangLov

I wish I had the numbers from the beginning (installed 2/2012) to compare.

I'll try to remember to catch the numbers on a clear day with humidity below 50.

After two years of never having to worry about rain, it's really frustrating to have extensive down time EVERY TIME it rains. I don't use broadband when I'm out mowing the lawn.

I'm going to see if I can get them out here for an alignment check for free. Last time they waived half the cost.

The house was built in May 2010, dish installed Feb 2012 (as soon as high-speed became available! I have no other broadband access where I live). When it needed alignment in 2013 I chalked it up to slight settling of the new house, since the installer said that the alignment tolerances are very tight for high-speed. Does that make sense?

Now they tell me it's extremely unlikely I'd need alignment again so soon, and their diags say there's nothing wrong, so they say it must be the weather.

Tech told me on site that my nearest trees are not a problem.



balsamea

join:2013-03-06
Plattsburgh, NY
reply to OldSatUser


said by OldSatUser:

MY SNR on the clearest of clear days never gets higher than say 7.6 or 7.7. It won't get any better than that for me because of my location to the beam's center. Almost always my SNR is the in the 6 range. But others can get a SNR that gets in the 9 to 10 range. It is just the reality of how the system is designed and setup, from the location of the satellite to the position of the beams.

Thanks for your reply, OldSat.

With your clear day SNR in the 6s like mine (right now perfectly clear sky and 6.7 to 7.1), do you know, to compare with mine:

1. Your SNR in rain? Notice any difference between light or heavy rain?

2. At what SNR you typically start losing the connection? 4, 5? For me it seems to be the high 4s.

3. Do you often lose connection during rain or overcast periods near periods of rain?

Thanks again.


balsamea

join:2013-03-06
Plattsburgh, NY
reply to DrStrangLov

said by DrStrangLov:

In the toilet means it don't work.

Cell phones don't work so well in there either.

DrStrangLov

join:2012-03-28

1 edit
reply to balsamea

said by balsamea:

5 v 12?

Exede offers 5/1 Mbps and 12/3 Mbps (download/upload) services.

"Darker orange is ViaSat-1 area (exede12). Pale orange is the area covered by augmented beams (exede5)."



said by DrStrangLov:

What is Tx RF Power when it rains?

quote:
23.8 typically in most of my rain checks, 26.2 in one recent check during rain. Down from 30-32 in clear weather.
Exede (aka ViaSat) uses (we hope) Adaptive Coding and Modulation (ACM)

What is ‘ACM’?

Adaptive Coding and Modulation is a technology which can automatically change the modulation and forward error correction or FEC of a link (referred to as MODCOD) to compensate for changes in link conditions – commonly weather induced (e.g. rain fade) but also due to changes in the RF environment (e.g. level changes, interference).
In clear weather, a better MODCOD for faster speeds is used, but when rain fade conditions exist, a different MODCOD is used.

When numerical value of Tx RF Power increases, it means more power is required...so, when you see values like 23.8, less power is being used; and it means your uplinks will be slower.

So, let me refine an earlier comment: When your uplink/downlink goes into Toliet (with equipment working OK) during light rain/etc:

1. Dish Alignment Issue
2. Engineers fumbled the signal "refinement" ball
3. MODCOD SNAFU

OldSatUser

join:2012-05-10
Fresno, OH
reply to Balsamea

I have seen a LOS when it is in the 2's. 4 - 5 (which would be typical for me in light rain) the signal maintains.



balsamea

join:2013-03-06
Plattsburgh, NY
reply to Balsamea

As the current t-storms approached, I monitored wx radar, modem status, and testmy.net speeds. Radar showed severe t-storms throughout the area, but they had not reached me at the moment.

SNR gradually dropped below 6, then 5. Browsing and speed still fine. When it reached 4.5, it stopped its usual fluctuating, locked there, and cable attenuation locked at 4.0. Unable to browse or run testmy. Modem lights DL solid and UL blinking.

Reset modem. It came back with very low and widely varying SNR, 1 to 3, but I had Internet and testmy was coming in with lower than usual but usable speeds, 6 - 10.

Contrary to my normal practice of shutting down during t-storms, I stayed on. While the t-storms raged over my head, rain pouring down in bucketloads, I had SNR varying widely in the 3s and 4s ... with good speed tests ... 9 to 11 DL vs the usual 15+/-. That's not bad at all.

So, in seriously bad weather (there is even a tornado watch not far south of here), I had only a brief loss of signal, at a transition point between just rain and a t-storm, regained with a modem reboot, then low SNR, but overall nothing to stop me from working.

This is what I had been accustomed to in the past, before that series of lengthy signal loss periods during 5 rain events in a row in May and July.

I guess I'll just wait and see. Maybe it was something temporary on the provider's end. SOMETHING was different in May and June, because SNR dropped much more for lesser weather conditions, even just overcast with no rain, and in a variety of cloud conditions at various levels in the atmosphere.

As I write this, t-storm has passed, leaving just rain. SNR 4.5-5.5, more often in the 5s. Speeds excellent 17-19.

BTW, on the map I'm right on the edge of the northeastern-most line of 314, just west of where it crosses the NY-VT border.

Thanks for the dialog. I'll report back if things degrade again.


OldSatUser

join:2012-05-10
Fresno, OH
reply to Balsamea

Keep in mind it isn't always the weather RIGHT over you, but the weather in the direction your dish is pointing to the satellite.

Don't try to become too transfixed on the Rx SNR value. Basically, your service either works or it doesn't. Nothing really in between



balsamea

join:2013-03-06
Plattsburgh, NY

Just found this (long quote below), which is what I will cite to DISH Support next time they tell me, "It's the weather."

According to this quote from Exede, it's usually NOT the weather, as was my experience for more than two years before the series of seemingly weather-related failures in May & June.

So, as DrStrangLov said, it could have been a weather-related modcod issue at their end, or else-wise within the system they use to accommodate weather conditions, but not likely simply a matter of weather itself as causative to my signal losses. I.e., yeah, it's weather, but only because their system is not amply doing what it normally does to accommodate weather.

Now that apparently my experience has returned to the way it was for more than two years before May -- no significant problems during a normal weather event -- I'm inclined to believe it was a temporary problem at their end, but I'll never know without surveying a hundred other customers in my area to see if others were affected.

I hope I never have to talk to Support about weather again (or anything else), but if they blame it on weather, I'll ask them to explain this:

From »help.exede.net/articles/General/4617

"Impact of weather on your service

"A brief explanation of the minimal impact weather could have on your service.

"Cloud cover and bad weather may take an occasional, typically minimal and temporary toll on your service. The microwaves that carry the Internet signal between the satellite and the ground have to pass through the atmosphere and, at times, stormy conditions.

"Connection speeds may lag a bit during rain and heavy snowstorms, but unless the storm is unusually severe, your connection should never be lost. That's because the Exede Internet system is designed to constantly be measuring the link between the satellite and the ground, and automatic, instantaneous adjustments to keep the signal strong occur in the background. [is this modcod?]

"A severe storm with thunder and lightning could impact service for a brief time, but it's unlikely it'd last more than 10 minutes. Even heavy storms without thunder and lightning should have little or no impact on the connection.

"The most perplexing %u2013 but rare %u2013 interruption happens under clear skies. Because the ground-based 'gateways' that serve the Internet up to our satellite may be far from your home, weather or other factors at the gateway location can affect service in other areas. [my problem could have been a gateway issue?]

"Bottom line, only heavy rain or wet snow threatens signal speed and/or connection. And unless the storm has knocked out actual infrastructure connected to our service, it's a temporary situation."

ONLY is a pretty strong word, as are "little or no impact" and "never." Are they lying? I don't think so, because their statement here reflects my experience in adverse weather events except for May-June 2014. Who knows how much Customer Service / Support knew of what was really happening at the time, but "it's the weather" is not an adequate answer.



balsamea

join:2013-03-06
Plattsburgh, NY
reply to OldSatUser

said by OldSatUser:

Keep in mind it isn't always the weather RIGHT over you, but the weather in the direction your dish is pointing to the satellite.

Understood.

said by OldSatUser:

Don't try to become too transfixed on the Rx SNR value. Basically, your service either works or it doesn't. Nothing really in between

I'm not sure what you mean. Isn't the typical speed degradation that comes with reduced SNR something "in between?" There is a direct correlation. If I'm hovering around 40% reduced SNR and speeds are 7 Mbps when normally 12-20, but no complete loss of connection, that looks like in-between working or not working, because that amount of speed reduction is noticeable and affects functionality ... especially for UL, when you might as well quit and go to the beach when it's under 1 Mbps ... during the problem periods I saw, it was dropping to less than 300 K. It's "working," but not adequately. In-between.

DrStrangLov

join:2012-03-28

said by balsamea:

typical speed degradation

I rather suspect when uplink "fumbles," so does your download speed(s).

Ground station "needs" to know when those packets are being recieved; satellite puts out a good signal, but I believe uplink is the weakest link.

Hence, Rx SNR may not be the indicator to watch...Tx RF Power might be the one, if MODCOD is operational.


balsamea

join:2013-03-06
Plattsburgh, NY

said by DrStrangLov:

Rx SNR may not be the indicator to watch...Tx RF Power might be the one, if MODCOD is operational.

I'll keep adding to my records to look for trends. So far, Tx RF averages 32.5 in good weather, low 20's in rain or dense overcast sky (considerable cloud concentrations at 3 levels).

Does that seem like typical behavior?

If there's a modcod problem, will that be reflected in Tx RF, separate from weather issues, as in lower number even though it's a clear day?

Thanks for the feedback.

DrStrangLov

join:2012-03-28

said by balsamea:

Tx RF...32.5 in good weather, low 20's in rain or dense overcast sky

MODCOD is working at your location...if higher numbered (32) is seen in bad weather with no Internet, then MODCOD didn't engage.


balsamea

join:2013-03-06
Plattsburgh, NY

said by DrStrangLov:

if higher numbered (32) is seen in bad weather with no Internet, then MODCOD didn't engage

Ah so! That could explain the brief loss of signal two days ago when we had rain.

This was after the most intense rain, but ... SNR was falling rapidly, and I was screen-clipping info. When SNR was still 5.3, I next looked at the Tria status, within the same minute (my screen clipper doesn't show seconds) and then immediately ran a speed test, then lost connection ... actually, the modem lights were all normal, but browsing was dead. At that moment, Tx RF was 33.8, vs its usual low 20's in rain, like you said.

Speeds weird, 1.4M DL, 2.2M UL (I have it all in screen clips, so it's not an operator error). UL was higher than DL, within the same Express Combined DL and UL test, where DL comes first. I suppose it's possible the connection gasped during DL then momentarily came back for the UL before dying. Or it was a false report.