Rain fade mitigation

Is anyone else suffering from rain fade this afternoon. I’m just west of Philly and we are getting the leading edge of a storm that is meant to last well into tomorrow morning.

It occurs to me that perhaps some sort of feed horn might mitigate the fade? I think that the few extra db’s of gain might be enough to over come it?

Screenshot%20at%202019-12-01%2015-24-26

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I’m getting intermittent fades and loss of lock here outside of Washington, DC too:

image

But my signal picks up again in a hurky jerky fashion to +2 to + 7 dB. I don’t think its rain fade, but a transmission problem. I checked @maxboysdad Jerry’s terminal in Utah, and he is not seeing the same thing. Ken

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I’m in michigan and seeing the same thing you are. I haven’t brushed the snow off the dish to see if the extra gain makes a difference.

No difference with a clean dish.

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Wow. Never seen SNR figures above about -11 before on my equipment Except for back in the L-Band days. That dish of yours is surely working hard. I took the opportunity to try peaking my LNB whilst the rain came down. I now have about a 50% or so decode. I also tried adding an empty baked beans can as a waveguide/feedhorn and that also brought it up out of the noise but I was holding it with my hand and so had to remove it. The bean can did win me a few more db’s though so that’s next on my list of improvements.

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Some interesting resources for bi-yearly solar fade
http://geosats.com/solaroutages.html
and general solar activity
https://www.spaceweather.com/
In today’s case almost certainly not the issue but information to keep in a mental troubleshooting checklist.

I did wonder actually if it was solar noise rather than rain fade?

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Are you talking about the first screenshot with snow on the dish? I was surprised too. I should have taken a picture.

Just to add a comment here, when the storms came through here Monday and Tuesday, my SNR did dip somewhat, sometimes as much as 6 dB. Most of the time when this occurs, it is when there is an accumulation of snow on the dish or the LNB. I have noticed a similar but lesser effect during heavy rain, but it does not lose lock during these events. I agree that it is more likely a transmission problem.

Not convinced about it being a transmission issue. We’d all have it at the same time. Seems from the thread here that we did not all suffer from it despite being available at the same time. I am currently in the middle of a heavy sleet/snow storm and am holding lock but yesterday in the rain I was not. Snow is said to be 10% of the density of rain according to NOAA. Perhaps that accounts for it? Snow buildup on your dish could equate to a quarter of an inch of standing water.

is it a system wide % drop? Could be fade at the uplink?
@Syed, do you contract out uplink or have your own rig?
I recall the transponders on SES and Astra are bent pipe not a digital transponders so below a certain point where the signal received at the satellite is too low weak up=weak down.
Even if we cant do a live systemwide Dreamcatcher status now a cool thing to have would be where we could read stats from individual, regional, and systemwide averages; in addition to the general statistics the data could for example be reworked to be not unlike a crude but huge passive radar network.

We had a similar situation occur last year, where @kenbarbi Ken was seeing loss of lock at Annapolis, MD, but my unit in Salt Lake City, UT, was not, and it was a minor problem at the feed point (terrestrial noise or something). It seemed like the perimeter of the “transmitted signal” from the satellite had moved, shrank or indented at the east edge for a short time, but was stable farther west. I am about 2100 miles almost straight west of @kenbarbi Ken.

@biketool We have our own uplink equipment, but that is only used for testing. For the public channels SES uplinks for us. Almost all currently operating commercial geostationary satellites are analog bent pipes. There are very few commercial digital payloads currently operating.

I dought it has anything to do with weather either as it is now a sunny day here and I still have random lock loss. With an snr in the positive I shouldn’t have packet loss but I’m losing approximately 20%. I’m also seeing a lower bitrate than normal.

On one hand I would have expect everything to be moving/moved to digital, but I guess a wide as possible analog bent pipe is more flexible than a fixed digital format; you can’t stuff analog down the throat of a digital hub/repeater sat but we send digital up and down analog every day for decades. Buffering is OK for data but assuming a primarily TV satellite needs to run something simple and dead headed when the re-transmitting hardware is at the end of a 36megameter string.

Today, with no precip of any sort I have a -9db s:n and 100% decode and 8100bps audio rate and 20216bps overall data rate. This is the best I’ve ever seen it. Clearly peaking the LNB in the rain helped enormously!! This reminds me vaguely of a trick from back in the day where one hangs a wet rag over the LNB to simulate rain fade? You would then peak for max signal.

I’m definately gonna try building a “proper” feed horn. If I can get another 3db’s out of the signal then I think I’ll be good in all weathers?

Anyone wanting to look in on my system can point their browser to http://g7ltt.dyndns.org:8866

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@Syed, do they do much shape tuning of the phased array?
If so do they communicate that with you?
Is there something from SES that we can look at to get satellite health and updates?
Back when I was hobbying around with amsats I loved how much open source data was available especially the user contact health reports.

Commercial satellites (geostationary or otherwise) are all black boxes to end users. I’ve heard that in some cases it is possible to receive and decode the TT&C/satellite health, but the operator does not actively promote reception of this data.

The current (and past) generation of satellites do not generally do any beam reshaping. There are some that have steerable reflectors, which just moves a predetermined pattern across a section of the globe. The next generation of GEOs are far more flexible and will supposedly be fully configurable across beam shape, EIRP, and frequency band. I’m referring to the new platforms from Boeing and Airbus.

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