Jump to content


Welcome to DBSTalk


Sign In 

Create Account
Welcome to DBSTalk. Our community covers all aspects of video delivery solutions including: Direct Broadcast Satellite (DBS), Cable Television, and Internet Protocol Television (IPTV). We also have forums to discuss popular television programs, home theater equipment, and internet streaming service providers. Members of our community include experts who can help you solve technical problems, industry professionals, company representatives, and novices who are here to learn.

Like most online communities you must register to view or post in our community. Sign-up is a free and simple process that requires minimal information. Be a part of our community by signing in or creating an account. The Digital Bit Stream starts here!
  • Reply to existing topics or start a discussion of your own
  • Subscribe to topics and forums and get email updates
  • Send private personal messages (PM) to other forum members
  • Customize your profile page and make new friends
 
Guest Message by DevFuse

Photo

Rain Fade Explanation


  • Please log in to reply
26 replies to this topic

#1 OFFLINE   RG6-Q

RG6-Q

    Mentor

  • Registered
  • 39 posts
  • LocationPUERTO RICO
Joined: Apr 21, 2013

Posted 11 August 2013 - 01:38 PM

I have heard you guys talk about 8psk/3/4-7/8 and maybe that is the answer to my question.

 

Why is it that when it rains or is cloudy some TP go down maybe 10 points while others maybe loose 2 points???? :bang



...Ads Help To Support This SIte...

#2 OFFLINE   RG6-Q

RG6-Q

    Mentor

  • Topic Starter
  • Registered
  • 39 posts
  • LocationPUERTO RICO
Joined: Apr 21, 2013

Posted 13 August 2013 - 04:24 PM

Thanks for the answer. :nono2:



#3 OFFLINE   P Smith

P Smith

    Mr. FixAnything

  • Registered
  • 19,849 posts
  • LocationMediterranean Sea
Joined: Jul 25, 2002

Posted 13 August 2013 - 04:33 PM

you know ... the answer would be require extensive and long research .. some ppl get PhD for find it



#4 OFFLINE   cj9788

cj9788

    Hall Of Fame

  • Registered
  • 1,659 posts
Joined: May 14, 2003

Posted 13 August 2013 - 05:04 PM

I am by far no expert but I can tell you that back in the day I had a one meter dish that I used on the 119 satellite and it had no rainfade issues at all while the small dish I had pointed at 110 would lose the signal completly. The rain and the clouds keep the signal from hitting the dish which causes the signal loss. Some TP's such as CONUS TP's have a stronger signal than a TP for a spotbeam. If I am wrong someone will come along and point it out I am sure. Also if your dish is not allinged correctly that may cause the signal troubles you desribed.



#5 OFFLINE   P Smith

P Smith

    Mr. FixAnything

  • Registered
  • 19,849 posts
  • LocationMediterranean Sea
Joined: Jul 25, 2002

Posted 13 August 2013 - 07:22 PM

usually SB tpns are more powerful



#6 OFFLINE   sregener

sregener

    Godfather

  • Registered
  • 592 posts
Joined: Apr 17, 2012

Posted 14 August 2013 - 04:47 AM

I have heard you guys talk about 8psk/3/4-7/8 and maybe that is the answer to my question.

 

Why is it that when it rains or is cloudy some TP go down maybe 10 points while others maybe loose 2 points???? :bang

 

What causes rain fade is that water blocks the frequencies that the satellite uses to communicate with the ground.  However, it does not affect all frequencies equally, nor are all the transponders delivering the same power.  There is also the problem of observation - I don't believe any Dish receiver can report the strength of all TPs on a satellite simultaneously, but can only test one at a time.  Thus, due to the variable nature of rain (it rarely falls at precisely the same rate for an extended period of time) that also has some impact.

 

Using more power helps some to mitigate rain fade.  A larger dish helps some.  But no dish can overcome it all, as a heavy enough rain will block all of the signal, even with a 2-meter dish.  That's just the reality of Ku-band.



#7 OFFLINE   neilo

neilo

    AllStar

  • Registered
  • 122 posts
Joined: Aug 07, 2006

Posted 14 August 2013 - 05:10 AM

I was wondering whether any of the newer DVRs have event/timer control recovery against this issue.  Last night we had a heavy rain during the 9 PM to 10 PM hour which caused a signal loss and so any event scheduled during that time would lose part or all of the recording.  Do newer DVRs recognize this and then record the next showing of this timer or do you still need to manually do that yourself?



#8 OFFLINE   Rafael

Rafael

    Mentor

  • Registered
  • 61 posts
  • LocationFort Lauderdale, FL / Caracas Venezuela
Joined: Jul 24, 2005

Posted 14 August 2013 - 07:49 AM

I totally agree, and just to add:

 

Rain Fade is an absorption o dissipation of a microwave (RF) caused by atmospheric rain and mainly in the wavelength of frequencies over 11 GHz (Ku, K, Ka, etc.)

This is why cable operators and satellite providers use their main feed out of C-Band (3 - 4 GHz). Here (over 11 GHz) the water drops or water vapor (clouds), based upon density

send the signals to different areas than intended or dispersed causing a signal attenuation, in other words it doesn't need to be raining to suffer rain fade, a very dense cloud could 

cause the effect.

 

As you may suppose low angle targets (satellites) could be affected more because precipitation could be present many miles away.

 

There are some other factors that could cause those 2 - 3 points to fluctuate, temperature in the atmosphere is other factor but only noticed very slightly.

 

Regarding CONUS Beam, normally satellite operators beam more power to the east coast which is said suffers more rain.

When a satellite beams 16 Transponders (odd or even) most likely they beam 8 tps in double power and 8 in single power to extend the birds lifespan.

So you might notice this when in rain fade effect.....


Edited by Rafael, 14 August 2013 - 07:50 AM.

  • RG6-Q likes this

#9 OFFLINE   RG6-Q

RG6-Q

    Mentor

  • Topic Starter
  • Registered
  • 39 posts
  • LocationPUERTO RICO
Joined: Apr 21, 2013

Posted 16 August 2013 - 11:35 AM

I totally agree, and just to add:

 

Rain Fade is an absorption o dissipation of a microwave (RF) caused by atmospheric rain and mainly in the wavelength of frequencies over 11 GHz (Ku, K, Ka, etc.)

This is why cable operators and satellite providers use their main feed out of C-Band (3 - 4 GHz). Here (over 11 GHz) the water drops or water vapor (clouds), based upon density

send the signals to different areas than intended or dispersed causing a signal attenuation, in other words it doesn't need to be raining to suffer rain fade, a very dense cloud could 

cause the effect.

 

As you may suppose low angle targets (satellites) could be affected more because precipitation could be present many miles away.

 

There are some other factors that could cause those 2 - 3 points to fluctuate, temperature in the atmosphere is other factor but only noticed very slightly.

 

Regarding CONUS Beam, normally satellite operators beam more power to the east coast which is said suffers more rain.

When a satellite beams 16 Transponders (odd or even) most likely they beam 8 tps in double power and 8 in single power to extend the birds lifespan.

So you might notice this when in rain fade effect.....

 

 

 

Your answer to low elevation which mine is 27 suffers the most, 110 at 36 suffers second and 61.5 with 68 is the powerhouse of signal.  To have signal lost on that one (61.5) either someone stole your dish or you  have a CAT 5 hurricane taking place.  

 

I have with your info come to the conclusion that elevation is paramount in signal strength.  Thanks to all.



#10 OFFLINE   Jim5506

Jim5506

    Hall Of Fame

  • Registered
  • 3,467 posts
Joined: Jun 07, 2004

Posted 16 August 2013 - 01:50 PM

Your answer to low elevation which mine is 27 suffers the most, 110 at 36 suffers second and 61.5 with 68 is the powerhouse of signal.  To have signal lost on that one (61.5) either someone stole your dish or you  have a CAT 5 hurricane taking place.  

 

I have with your info come to the conclusion that elevation is paramount in signal strength.  Thanks to all.

Low elevation in clear weather should not be a major factor.  As long as you are in the footprint the signal should be strong.

 

From your signal strengths it looks like your dish is misaligned.


Tuners: Hopper 2000; Hopper w/Sling; 3 Joeys; Samsung SIR-T351; Accurian 6000;2 X HD TiVo; 2 X TiVo Series 2 Stand alone; Panasonic Showstopper 2000
Dish 1000.2 @ 110, 119, 129; dish 500 @ 61.5
Antennas - CM4228; RS U75-R; coathanger; Funke PSP.1922 (stillin the box); paperclip
Displays: Sony VPH D50Q with HD Fury HDMI input; Hitachi 57F59; Sony Bravia LCD;Sanyo 32" LCD; Panasonic 42" plasma
Sony 80GB PS3; Toshiba HD-DVD

Give me a Finco colinear array and I'll rule the world - HA-HA-HA-HA!

#11 ONLINE   RBA

RBA

    Godfather

  • Registered
  • 340 posts
Joined: Apr 14, 2013

Posted 16 August 2013 - 05:16 PM

usually SB tpns are more powerful

Spotbeams are stronger if you are centered in the beam as you move further from the center the power drops off more rapidly.



#12 OFFLINE   P Smith

P Smith

    Mr. FixAnything

  • Registered
  • 19,849 posts
  • LocationMediterranean Sea
Joined: Jul 25, 2002

Posted 16 August 2013 - 06:52 PM

Spotbeams are stronger if you are centered in the beam as you move further from the center the power drops off more rapidly.

Only if you're out of DESIGNED area !



#13 OFFLINE   cj9788

cj9788

    Hall Of Fame

  • Registered
  • 1,659 posts
Joined: May 14, 2003

Posted 16 August 2013 - 07:40 PM

Only if you're out of DESIGNED area !

 

I supose that means there are no longer any fringe areas within a DMA's spotbeam. I know that was an issue several years ago.......



#14 OFFLINE   James Long

James Long

    Ready for Uplink!

  • Super Moderators
  • 39,739 posts
Joined: Apr 17, 2003

Posted 16 August 2013 - 08:08 PM

The newer satellites have better designed spotbeams than the originals.

The original spot beams were mostly circles with a focus point. Some markets were completely covered by their spots, some markets were on the fringe of the beam. Some of the larger markets did not have a spot available that effectively covered the entire market.

Modern spotbeams are not all simple circles. They are shaped areas ... and with dozens per satellite and multiple satellites it is easier to find the right beam to cover an entire market effectively.


As far as the fade question ... pick a a good weather day, aim the satellite dish as accurately as possible to give the best signal across ALL transponders on each satellite. With a multi orbital location dish you will need to compromise and sacrifice a high signal on one location to get a better signal on the next slot. Then when all is the best it can be write down your numbers.

On your rain fade days look to see which transponders you are losing the most on. Losing "10 points" on a transponder/spot that is your best signal is not going to be as critical as losing "4 points" on your weakest transponder ... as long as your worst signal is still good enough to receive the points don't matter.

One thing I noticed on my multi orbit receive dish is that I was losing more signal on 61.5 (where my spotbeam locals are) during heavy storms than on 72.7 (where ConUS Eastern Arc HD is). After the storms cleared I took a look and found that a tree I had trimmed back a couple of years ago was encroaching on the 61.5 line of sight. Wet leaves made it even more of a problem. It got trimmed and the fade is gone again.
  • cj9788 likes this
Welcome to DBS Talk - Let's talk about DBS! (The Digital Bit Stream)
DISH Network vs DirecTV: HD Channel List - DISH Network HD Capacity, HD Conversion and more.
DISH Network complete channel lists and lists by satellite location are in The Uplink Activity Center.
Unless otherwise noted, I speak for myself. Content is not controlled by DISH Network, DirecTV or any other company.

#15 OFFLINE   cypherx

cypherx

    Hall Of Fame

  • Registered
  • 2,768 posts
  • LocationPA - Berks County
Joined: Aug 27, 2010

Posted 16 August 2013 - 08:26 PM

I think t would be cool if the receiver detected rain fade, it would just display the stream via your broadband connection (if available). I'm just not sure how the system could tell the difference between rain fade or other obstructions. Perhaps some kind of beacon signal sent at different bands. By measuring the signal characteristics of it, along with local radar maps (you know it can get that data via TV apps), it could tell that it's rain fade.

You have pretty many channels available on the ipad / iPhone, and the quality is HD... It's all on the same network at home so I say let the receiver point itself to these same feeds as well. Heck maybe a two tuner DVR with both tuners occupied could watch a 3rd program via the live streaming broadband connection.


Sent from my iPad using DBSTalk mobile app

- > Link to my setup thread< -

My  DirecTV HD WISHLIST:  NickJR, Nicktoons, Revolt.TV, FXM, We, Oxygen, The Hub, Fuse, GSN, Sprout, GAC, Esquire, MTV2, BBC World News, Ovation, Reelz , Sundance, Up, Music Choice Play HD (formerly SWRV), Al Jazeera America, Military Channel, NASA

My DirecTV SD WISHLIST: MTV Hits, MTV Jams, Music Choice, Youtoo TV

 

---
HR24-200
H24-200


#16 OFFLINE   P Smith

P Smith

    Mr. FixAnything

  • Registered
  • 19,849 posts
  • LocationMediterranean Sea
Joined: Jul 25, 2002

Posted 16 August 2013 - 08:45 PM

If you will take a look into DVB-S2 standard you'll find a provision (to change many parameters of a modulation, error correction, frame size, etc) to adapt to any influence between sat and user's STB;

it has own price thought - a constant feedback, so Internet connection would fulfill the requirement



#17 OFFLINE   Rafael

Rafael

    Mentor

  • Registered
  • 61 posts
  • LocationFort Lauderdale, FL / Caracas Venezuela
Joined: Jul 24, 2005

Posted 16 August 2013 - 09:17 PM

I have with your info come to the conclusion that elevation is paramount in signal strength.  Thanks to all.

RG6-Q,

 

Your conclusion applies only when you consider Rain fade factor, otherwise, there are several other factors.

 

Under ideal conditions in the reception area: located in conUS footprint, perfect alignment, ideal antenna size-gain, non cable loss (cable run within the range it's designed for not causing noticeable loss), good weather conditions, etc, etc. The signal strength displayed on your receiver's meter (not so accurate as a spectrum analyzer) depends on built in electronics in the ird and the lnbf; that said each receiver or lnbf has different responses even though the manufacturer claim they are the same, but each electronic component isn't exactly the same but very close. Also the software is manipulated to give more stability, parameter such as FEC could be adjusted to allow more stable signal before pixelating or loosing lock on the signal.

 

For example I can open a 50 lnbf box and try them all with the same ird and antenna, some will give tremendous readings in average, others will respond better in higher odd and lower even, etc, etc...no electronic component in the world will have an exact match but there should operate in an acceptable range.

 

Also antenna gain is other factor, as you increase the antenna gain aiming needs to be very accurate because it also has narrower  beamwidth. Believe it or not when in Fringe you can even notice the different footprint of the bird based upon the satellite's manufacturer (US satellite operators mainly uses SSL or Boeing) but fortunately you're not so deep in fringe!!!!!

 

There are more factors, but I hope you get the picture.


Edited by Rafael, 16 August 2013 - 09:23 PM.

  • RG6-Q likes this

#18 OFFLINE   RG6-Q

RG6-Q

    Mentor

  • Topic Starter
  • Registered
  • 39 posts
  • LocationPUERTO RICO
Joined: Apr 21, 2013

Posted 17 August 2013 - 12:55 PM

Your answer to low elevation which mine is 27 suffers the most, 110 at 36 suffers second and 61.5 with 68 is the powerhouse of signal.  To have signal lost on that one (61.5) either someone stole your dish or you  have a CAT 5 hurricane taking place.  

 

I have with your info come to the conclusion that elevation is paramount in signal strength.  Thanks to all.

These are not my signal levels, they are elevation.  I get on a clear day on 119 TP1 SPOT is 88, TP 3 SPOT is 94, TP 16 Non-Spot is 80 and so forth.  It just seems to me that elevation at 27 with signal of say 80 is less than 80 on a 45 degree angle dish.  Clouds seem to always accumulate low in the horizon.  Does the signal have to travel through more rough weather at low elevation than higher ones.????



#19 OFFLINE   Jim5506

Jim5506

    Hall Of Fame

  • Registered
  • 3,467 posts
Joined: Jun 07, 2004

Posted 17 August 2013 - 01:04 PM

Depends on the weather.

 

If you have a storm between your dish and the satellite, there will probably be more water vapor between the dish and the satellite, therefore more signal scattering/attenuation, but with clear skys little difference will be noted.

 

Normal cumulus clouds will not do too much damage to the signal, they are just visable water vapor whereas a storm can include ice being thrown up into the cloud tops (hail) and rain plummeting downward.

 

Rain drops are a much higher concentration of water molecules than clouds.


Tuners: Hopper 2000; Hopper w/Sling; 3 Joeys; Samsung SIR-T351; Accurian 6000;2 X HD TiVo; 2 X TiVo Series 2 Stand alone; Panasonic Showstopper 2000
Dish 1000.2 @ 110, 119, 129; dish 500 @ 61.5
Antennas - CM4228; RS U75-R; coathanger; Funke PSP.1922 (stillin the box); paperclip
Displays: Sony VPH D50Q with HD Fury HDMI input; Hitachi 57F59; Sony Bravia LCD;Sanyo 32" LCD; Panasonic 42" plasma
Sony 80GB PS3; Toshiba HD-DVD

Give me a Finco colinear array and I'll rule the world - HA-HA-HA-HA!

#20 OFFLINE   Rafael

Rafael

    Mentor

  • Registered
  • 61 posts
  • LocationFort Lauderdale, FL / Caracas Venezuela
Joined: Jul 24, 2005

Posted 18 August 2013 - 08:17 AM

These are not my signal levels, they are elevation. I get on a clear day on 119 TP1 SPOT is 88, TP 3 SPOT is 94, TP 16 Non-Spot is 80 and so forth. It just seems to me that elevation at 27 with signal of say 80 is less than 80 on a 45 degree angle dish. Clouds seem to always accumulate low in the horizon. Does the signal have to travel through more rough weather at low elevation than higher ones.????

I believe the answer to this is your location (Puerto Rico) assuming your dish is perfectly aligned.
The spot beams you have with higher levels means that indeed they're covering well the island......
But the conUS beam isn't 100% beamed to your area, their main target is with continental 48 states, and then shared with your area (USVI & PR), they aim in such a way that the spill over feeds your area with good enough power to have a respectable level of 80.

What size antenna do you have?

Here's a link so you can see the conUS beam shape:

http://www.satbeams....embed?beam=6269

Edited by Rafael, 18 August 2013 - 08:48 AM.





Protected By... spam firewall...And...