Losing DVB-S2 signals during the day

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rrob311

rrob311

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I have been losing most of my HD DVB-S2 signals during the day. First I lost everything on 125w. Now I am losing the ABC HD feeds and Live Well Network feeds on 99w. They work in the morning but midday they are gone. They don't come back in until the evening. Could this be a solar glare problem?
 
SatelliteAV

SatelliteAV

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Try shifting your LNBF up or down in 1MHz steps and see if the stations come back in. This could be the drift of the LNB LO frequency in the heat of the day.

Chilled LNBs also have better performance. Maybe someone wants to invent a chill pack for LNBs and LNBFs? I can picture a small insulating blanket with cooling tubes running of of the LNBF power..... :cool:
 
rrob311

rrob311

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I will try that but I ran new blind scans and got different frequencies once but in the middle of the day I completely lose quality. I got the signals back for the most part right now but they are choppy.
 
SatelliteAV

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Does the Signal Quality decrease as the pixs become choppy?

When you lose the channels or they become choppy, have you tried a blind scan at that time?
 
rrob311

rrob311

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ya, sometimes it will even jump from like from 60 to 0 and just go up and down constantly as it chops. This is on the openbox.

during the day when I run the blind scan again they come up close to the same but no quality or picture during the day.
 
Diamond Jim

Diamond Jim

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Aug 18, 2004
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I had that last week. Turned out to be an alignment problem. Moved the dish just a hair to the east and picked up 5 points on the strength and perfect video.
 
Dee_Ann

Dee_Ann

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May 23, 2009
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I have the same problem with RTV S2 channels on 87 in the day. I guess I really need to get off it and go adjust that beast...
 
sergei

sergei

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Aug 29, 2007
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I have been losing most of my HD DVB-S2 signals during the day. First I lost everything on 125w. Now I am losing the ABC HD feeds and Live Well Network feeds on 99w. They work in the morning but midday they are gone. They don't come back in until the evening. Could this be a solar glare problem?

You show having two dishes and you didn't mention which dish was having the issue, is it both or just one?
 
rrob311

rrob311

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You show having two dishes and you didn't mention which dish was having the issue, is it both or just one?

I am losing quality on both of the dishes. One is a 39" Ku and the other is a 12' C band.
 
I

icu1954

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Sep 1, 2010
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try deleting all of your transponders on that sat and rescan everything back in.....may be a transponder overload,it has worked for me.
 
Anole

Anole

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Sep 22, 2005
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new product idea?

Chilled LNBs also have better performance.
Maybe someone wants to invent a chill pack for LNBs and LNBFs?
I can picture a small insulating blanket with cooling tubes running off of the LNBF power..... :cool:
I remember some years back, when CPU coolers were thermoelectric.
Same technology as in the center-console 'fridges in minivans.
You run a lot of DC through 'em, and they get cold on one side, and hot on the other.
They actually pump heat from what becomes the cold side, out to fins in the air (or under a fan).
Reverse the power, and they pump heat the other way.

Combined with a thermistor to maintain reasonable temperatures in hot 'n freezing climates, ya might maintain cool in the tropics and warm in the blizzard. :up
 
PopcornNMore

PopcornNMore

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Mar 20, 2005
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This is also why channels are stronger during the winter months due to the cold. Plus the leaves are gone from the trees.
 
SatelliteAV

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PopcornNMore said:
This is also why channels are stronger during the winter months due to the cold. Plus the leaves are gone from the trees.

Not so much from the heated dish electronics, but rather to the environmental RF traps. :)

Thermal heating / cooling does affect the RF layers surrounding the earth and raise the terrestrial noise level, decreasing the signal to noise ratios. The increased heat does cause the signals to be slightly attenuated in summer months, but trapped pollution by inversions and free floating particulates such as exhaust, smoke from forest fires, volcanic ash, etc. will cause much greater attenuation of satellite signals.
 
rrob311

rrob311

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Not so much from the heated dish electronics, but rather to the environmental RF traps. :)

Thermal heating / cooling does affect the RF layers surrounding the earth and raise the terrestrial noise level, decreasing the signal to noise ratios. The increased heat does cause the signals to be slightly attenuated in summer
months, but trapped pollution by inversions and free floating particulates such as exhaust, smoke from forest fires, volcanic ash, etc. will cause much greater attenuation of satellite signals.

Does humidity affect it more? I get all of the abc s2 feeds and mytv and lwn. Its humid here by the river especially
 
SatelliteAV

SatelliteAV

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Does humidity affect it more? I get all of the abc s2 feeds and mytv and lwn. Its humid here by the river especially

I have never performed any tests on the affect of humidity on RF propagation. The reports that I have read indicate that water vapor becomes an issue with higher frequencies (20GHz and above). I would believe that it would have negligible yet measurable attenuation with C and KU band signals.

One fact that is often not addressed is that rain and ice depolarize KU band signals as well as attenuate through the density.
 
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pedrogarcia

pedrogarcia

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Dec 27, 2008
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My understanding was that depolarisation on Ku (linear only) occurs in the ionosphere due to ionised electromagnetic Faraday rotation. In the lower troposphere Ku (lin & circ) particularly encounters resonant absorption due to oxygen in water vapour, in addition to the attenuation due to rain,fog, sand or pollution. [Now the Soap box bit} The technology and cost required to get a satellite's necessary low powered signal to earth is huge and then Dsh and Drect use a cheap, compromise small dish and their customers wonder why they lose signal. They should learn from the FTA guys.
 
stanleyjohn

stanleyjohn

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Mar 25, 2010
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Im starting to buy into this theory that during the day something is going on high above causing a S2 signal to weaken somewhat causing problems getting RTV on my 6 ft dish.Sig great from late evening till early mourning then pixel breakup.Dont think its a problem at ground level with sunshine and heat because dark cloudy days causing same effect.As a side note!i didnt have this problem during the winter months.
 
SatelliteAV

SatelliteAV

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Uplinkers usually have gear that monitors and automatically adjusts the power levels to maintain the levels contracted on the link budget with the satellite platform. It might be that the uplinker does not have automatic function and outputs a fixed wattage. Sometimes this is complicated by AGC settings on the satellite itself, poor station keeping (satellite positioning within the slot or angle) by the ground controller or a misaligned uplink dish.

Later today I will track down the articles regarding depolarization of linear Ku by rain and ice. Interesting reading!
 
SatelliteAV

SatelliteAV

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My understanding was that depolarisation on Ku (linear only) occurs in the ionosphere due to ionised electromagnetic Faraday rotation. In the lower troposphere Ku (lin & circ) particularly encounters resonant absorption due to oxygen in water vapour, in addition to the attenuation due to rain,fog, sand or pollution.

A few links referencing KU-band Rain and Ice depolarization that you might find interesting:

www.ursi.org/proceedings/procGA08/papers/F05p7.pdf

http://www.wtec.org/loyola/satcom2/toc.htm ( http://www.wtec.org/loyola/satcom/c4_s1.htm )


Also Google KU Depolorization for additional links that I was unable directly link in this post.
 
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