Rain fade more than anticipated

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olliec420

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Most of you probably know by now I'm on my first c-band experience. Today is the first rainy day since I hooked it up and man is the rain fade waaaaay worse than I anticipated. I was under the impression that c-band can power through most rain. Granted I am on 7.5' but damn, its hardly raining and I'm on Pursuit on 87 and it is unwatchable. Clear sky S is 91 and Q is 77. Attached is radar view. Yellow to the south west of me, I'm in the clearer area in the middle.

 

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KE4EST

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This is what I am thinking also. Must be something else going on. I have never experienced rain-fade on C-Band unless it was a very heavy snow storm...or a transponder that was on the threshold.
This does not seem to be the case with you. Anyway the dish has moved on one axis or the other, water getting in on connections somewhere, or LNB not tightened and moved?
 

Shicks4

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I had some weird stuff happen with my c-band (all satellites, multiple transponders) just a little before this was originally posted. But about 20 minutes (noticed it around 6:30 pm central)went by and everything came back. Its sunny and 70 degrees here today. I thought maybe my skew motor went out but it was working fine, then i thought my motor was missing counts, but everything checked out. About the time i was thinking maybe my receiver was going out it all came back.
 
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Radioguy41

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This is what I am thinking also. Must be something else going on. I have never experienced rain-fade on C-Band unless it was a very heavy snow storm...or a transponder that was on the threshold.
Same here. I have a 7.5' dish and the only time I have ever experienced fade is during a real heavy snow storm or if the dish has filled up with snow. The only other condition that can interrupt the signal like that is shortly before, during, and right after the Spring and Fall solstice and then only if you happen to be on a specific bird as the sun passes behind it. To have severe fade in a light rain would seem to indicate some other problem as Mike has suggested.
 
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olliec420

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I went and watched a movie in another room for two hours and just decided to check again before bed and now it's working flawless.
Like someone said, I too thought maybe water getting in a connector? But no way, the water would have to travel up the cable and under the lnb cover and I have 3 drip/service loops under the cover before the connection. There are no other connectors until the receiver in the house, it's one long cable. Strange. Well I'll just have to see what happens next time it rains.

I'm used to small ku dishes that go out all the time in rain. Maybe this was just a coincidence my receiver was acting up I hope.
 

olliec420

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I had some weird stuff happen with my c-band (all satellites, multiple transponders) just a little before this was originally posted. But about 20 minutes (noticed it around 6:30 pm central)went by and everything came back. Its sunny and 70 degrees here today. I thought maybe my skew motor went out but it was working fine, then i thought my motor was missing counts, but everything checked out. About the time i was thinking maybe my receiver was going out it all came back.

That's weird. Maybe our receivers went on strike and we didn't get the memo.
 

Shicks4

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well it was weird, that all i know. litterally 2/3 of all transponders stopped receiving signal and it was like i was only receiving vertical transponders which is why i assumes it was my servo motor. So i visually checked that. at about the time i decided to swap the x2 reciver back in everything came back, like i was standing there with the x-2 receiver and fixing to power off the linkbox and everything came back.
 

Shicks4

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What voltage are you providing to the LNB? Remember that LNBs require fixed18Vdc to operate and the 13Vdc supplied by FTA receivers in Vertical polarity is not adequate.
still set to 18v fixed like to told me to do when i set it up, even double checked that first, and the receiver is set up at 18/13v where horizontal is 18 and vertical is 13. I didnt change any settings it just came back all of a sudden.

It was weird like there must have been some kind of interference. Has worked perfectly since it came back. When it was down i did check the signal and quality and the quality was doing the same thing that heros, decades and movies does, bounced up and down with no lock. Lasted about 30 to 45 minutes and literally as i was reaching over to power it down to see if it was the receiver it all came back. Receiver im using is linkbox 9000i local. Even checked the connections on the rear of the asc-1 to make sure nothing had came loose. Was really odd. Only thing left to change when i came back was receiver and coax but i never got that far. Havent checked it this morning as i havent made it over to the shop yet. but it worked the rest of the evening while i was in the shop working.

At first i had wondered if my coax was not all the way tight as i have been swapping in and out with the wetek play 2 testing what the factory software would do, Which i need to share findings in another thread. Only reason i mentioned it going out in this thread was it happened to me around the same time frame. Only time i have ever had an issue with my dish other then this was if the wind was blowing out of the north west over 50 mph, or when it had 1/2" of ice on it.
 
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wvman

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Most of you probably know by now I'm on my first c-band experience. Today is the first rainy day since I hooked it up and man is the rain fade waaaaay worse than I anticipated. I was under the impression that c-band can power through most rain. Granted I am on 7.5' but damn, its hardly raining and I'm on Pursuit on 87 and it is unwatchable. Clear sky S is 91 and Q is 77. Attached is radar view. Yellow to the south west of me, I'm in the clearer area in the middle.



Are you sure your dish is tuned properly? I'm using a 7 1/2 foot myself, and I rarely lose signal because of rain. It has to be a super heavy rain. I have lost signal when the clouds were really saturated with rain. I've had 1 1/2 foot of powdery snow on mine and still watched TV. That changed when it started to melt and turned into a wet snow. I don't know if that's the case with yours, but I'd be suspicious.
 

olliec420

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Are you sure your dish is tuned properly? I'm using a 7 1/2 foot myself, and I rarely lose signal because of rain. It has to be a super heavy rain. I have lost signal when the clouds were really saturated with rain. I've had 1 1/2 foot of powdery snow on mine and still watched TV. That changed when it started to melt and turned into a wet snow. I don't know if that's the case with yours, but I'd be suspicious.

Well I don't really know because its my first go with c-band but last night everything was flawless. If you look at the video, the signal was going up and down. Very weird. I will just see what happens next time it rains, it could have just been fluke, maybe the receiver was messing up needing to be reset. I get what I think is a pretty strong signal, on my birdog I peaked and locked it down on 97% Q aimed at 91° which is my true south so I don't know. Going to try to spend some more time with it this weekend. If it was rain fade most likely the signal would not be "jumping" like that I would think right? It would go on and off and on and off and on and off (as seen in the video).
 

Shicks4

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Pensacola,isn't there a Naval air station there?Radar and other who knows rf are not your friends ;)
Actually yeah Pensacola NAS is there, NAS Whiting Feild, and just down the road is Eglin AFB, radar domes dotted along the coast. Spent several months at Eglin on the UAV program.
 
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Shicks4

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Dropped the MOAB someplace in there for testing while i was working there too so there is at least some advanced weapons testing that occurs in the area too.
 
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olliec420

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Pensacola,isn't there a Naval air station there?Radar and other who knows rf are not your friends ;)

Sure is, but shouldn't those be on other freqs for the most part?

Actually yeah Pensacola NAS is there, NAS Whiting Feild, and just down the road is Eglin AFB, radar domes dotted along the coast. Spent several months at Eglin on the UAV program.

Yeah that is most but there are even more than that. Im only a couple miles from our regional airport as well. Eglin is larger than Rhode Island, we can hear the bomb tests they do over there from the house.

Dropped the MOAB someplace in there for testing while i was working there too so there is at least some advanced weapons testing that occurs in the area too.

Then they first tested the MOAB, the local news was telling us to expect it for a couple weeks before hand. I was young and don't remember hearing or feeling it when they did it but I do remember the hype leading up to.
 

Titanium

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If this happens regularly, use a spectrum display to see if the noise floor is raised during the outage or if the satellite signal is reduced. Easy to figure out if the problem is because the satellite signal is being attenuated or interference is wiping out the satellite signal.

A cheap SDR RTL USB dongle connected to a PC or android and placed inline with a voltage blocked splitter would work fine if you don't have access to a satellite meter with a calibrated spectrum display. Just tune the SDR to the IF of one of the problematic transponders ( LO Frequency minus the C-band TP frequency).

Example: 5150 - 3900 = 1250 IF. Take note of the dB strength with e SDR in fixed gain mode. Also tune to a unused frequency between the TPs and not the noise level in dB (see satsignature.com for real-time spectrum display of active frequency range). This measurement is the noise threshold level and it will rise or fall with interference. Compare the peak TP measurement to the noise threshold and this will provide the approxiomate SNR (Signal to Noise Ratio). An increase in the SNR is good! A decrease in the SNR is bad and if the margin gets too small, the transponder will not lock or decode.

Radar should be outside the C-band frequency range, but harmonics or other onboard gear could be the cause.
 
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Shicks4

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Sure is, but shouldn't those be on other freqs for the most part?



Yeah that is most but there are even more than that. Im only a couple miles from our regional airport as well. Eglin is larger than Rhode Island, we can hear the bomb tests they do over there from the house.



Then they first tested the MOAB, the local news was telling us to expect it for a couple weeks before hand. I was young and don't remember hearing or feeling it when they did it but I do remember the hype leading up to.
Yeah there are more testing facilities i was just naming ones that were off the top of my head. I guess what i was getting at is there is a lot of testing going on in your area for a multitude of things. You were a kid when they dropped the MOAB? jeez that must mean im getting old.......... I was in the area so i felt it, didnt work on that project though. Not saying anything they are testing is the culprit but id wager money they have all kinds of gadgets that could interfere with almost any type of consumer device that receives a signal. Of course Titanium knows way more about these things then i do as its in his wheelhouse, and he knows what hes talking about.
 

olliec420

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Yeah there are more testing facilities i was just naming ones that were off the top of my head. I guess what i was getting at is there is a lot of testing going on in your area for a multitude of things. You were a kid when they dropped the MOAB? jeez that must mean im getting old.......... I was in the area so i felt it, didnt work on that project though. Not saying anything they are testing is the culprit but id wager money they have all kinds of gadgets that could interfere with almost any type of consumer device that receives a signal. Of course Titanium knows way more about these things then i do as its in his wheelhouse, and he knows what hes talking about.

Yeah I wanna say I was in high school when they did that. When was that about?
EDIT: No it was 2003, I had just graduated a couple years earlier so yeah I'm not that young lol.

 

waylew

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Well I'll put it this way,I'm within a half mile of the main shipping channel of the St Lawrence Seaway,every time a ship goes by everything horizontal on Cband gets wiped.
 
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