1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.
  2. Welcome to the new DBSTalk community platform. We have recently migrated to a community platform called Xenfono and hope you will find this change to your liking. There are some differences, but for the most part, if you just post and read, that will all be the same. If you have questions, please post them in the Forum Support area. Thanks!

Trying to sort out rain fade issues - transponder map anywhere?

Discussion in 'DIRECTV General Discussion' started by carillon, Jul 6, 2013.

  1. Jul 6, 2013 #1 of 37
    carillon

    carillon Legend

    168
    0
    Nov 14, 2007
    I'd like to know if there is a spreadsheet or webpage that will tell me which satellite and transponder individual channels are coming from. Having a moderate rain right now and some HD channels are unavailable while others are. Just curious to know so I could check the signal strength on individual transponders that provide HD channels that are out.

    Thanks!
     
  2. Jul 6, 2013 #2 of 37
    veryoldschool

    veryoldschool Lifetime Achiever DBSTalk Club

    42,649
    338
    Dec 9, 2006
    1 person likes this.
  3. Jul 6, 2013 #3 of 37
    peds48

    peds48 DIRECTV A-Team DBSTalk Club

    18,431
    913
    Jan 10, 2008
    NY
    But note that there is more to this that the "quality" signal that the receivers shows. You can have "excellent" numbers on transponders, but your "signal power" and/or SNR could be very low. Without the appropriate tools, it is very hard to troubleshot this issue, if you have any.
     
  4. Jul 7, 2013 #4 of 37
    carillon

    carillon Legend

    168
    0
    Nov 14, 2007
  5. Jul 7, 2013 #5 of 37
    carillon

    carillon Legend

    168
    0
    Nov 14, 2007
    I'm sure you are right, I don't have any tools or knowledge so looking at the transponder strength is all I have to work with. I posted my numbers in a separate thread and was told they were excellent.

    http://www.dbstalk.com/topic/205744-spreadsheet-available-anywhere-that-shows-signal-strength-numbers/page-2
     
  6. Jul 7, 2013 #6 of 37
    jimmie57

    jimmie57 Hall Of Fame

    6,391
    292
    Jun 26, 2010
    Texas City, TX
    After you click on the link supplied by veryoldschool, , scroll to the bottom of the first post and look for this spread sheet: TPN_MAP_Domestic_130703.xlsx
    Open it up and all the information you need should be there.

    Edit: actually I guess I copied the link directly to the spreadsheet. Just click on it and it should open.
     
  7. Jul 7, 2013 #7 of 37
    P Smith

    P Smith Mr. FixAnything

    21,337
    127
    Jul 25, 2002
    W.Mdtrn Sea
    Here we see someone with missed knowledge what has been posted at the forums.

    The signal's numbers _are_ SNR, find my post where I take time and plot the curve: SS vs SNR [they named it internally as CNR].
     
  8. Jul 7, 2013 #8 of 37
    slice1900

    slice1900 Well-Known Member

    6,552
    604
    Feb 14, 2013
    Iowa
    If only a 'moderate' rain causes loss of signal, and this isn't a case where the rain is moderate where you are but very heavy nearby (you can get rain fade even without a single drop ever hitting your house if big storm is in the right place just south of you) you probably don't have optimal signal during clear conditions. That's where you want to start with checking things. You should be in the upper 80s to upper 90s for all transponders on 99c, 103ca and 103cb. If you aren't, you either need your dish to be better aligned or have some other issue that needs to be rectified in your system.

    If you have good numbers when clear, but you see very low numbers or 0s during rain, either the rain isn't as moderate as you think or water is getting in something it shouldn't - you can test the latter by hitting your dish and all external satellite cabling/switches/splitters/etc with a quick shot from a hose to get it wet.

    Rain fade will be mostly an all or nothing proposition for the HD channels. If you are completely losing some HD channels, but other HD channels are coming in perfectly, there is probably something else wrong with your system. Bad cable, bad LNB, that sort of thing.
     
  9. Jul 7, 2013 #9 of 37
    HoTat2

    HoTat2 Hall Of Fame

    7,083
    165
    Nov 16, 2005
    Los...
    Found here in the attached thumbnail for those interested;

    http://www.dbstalk.com/topic/205263-at9-dish/?p=3142133
     
  10. peds48

    peds48 DIRECTV A-Team DBSTalk Club

    18,431
    913
    Jan 10, 2008
    NY
    Mr. "fixanything" I guess you missed the signal power part. You can have 90s on transponders but you can be sitting at the "floor" of the signal power any signal fluctuation will give FF/pix
     
  11. veryoldschool

    veryoldschool Lifetime Achiever DBSTalk Club

    42,649
    338
    Dec 9, 2006
    It's hard for me to see how this would be true.

    "If" the receiver is showing 90s, it's hard to see how there would be low RF power.

    "If" the 90s were at the dish [meter], "then" there could be too much loss to a receiver, but the CNR should also show a drop, which means on a "good day" it won't show 90s on the receiver.

    With a SWiM, there is almost nothing you can do after the dish to improve/help rainfade.

    "Testing" has shown rainfade to be in/at the LNA on the input of the LNB.
    The LNB outputs so much noise, that you can have -30 dBm [or more] "RF power" with NO input signal [and no CNR].
     
  12. peds48

    peds48 DIRECTV A-Team DBSTalk Club

    18,431
    913
    Jan 10, 2008
    NY
    When I did some "testing" with AIM, I lowered the signal power by adding splitters, I was geting the same numbers (transponders) when I did the test with -47dB then when I was getting -57dB. But we know that -57dB is almost at the signal "floor" of DirecTV recommended -60dB (safe) or -65dB (all gone)
     
  13. veryoldschool

    veryoldschool Lifetime Achiever DBSTalk Club

    42,649
    338
    Dec 9, 2006
    "Yeah" I thought you were going down that road.
    Getting the same numbers with -47 & -57 dBm sort of shows what I was saying.
    "With a SWiM", the AGC will keep the level constant, so "the fade" is in the LNA.

    I've been able to get good numbers at around -70 dBm, but this will vary between receivers [chip performance] and it isn't the way a good system is setup.

    "The thing is" it doesn't matter if the receiver input level is -60 dBm or -30 dBm for rainfade.
    I wish it was, but the LNBs output so much noise that "Rainfade" is all in the LNA [first stage of the LNB] as that is where the CNR is set.
     
  14. P Smith

    P Smith Mr. FixAnything

    21,337
    127
    Jul 25, 2002
    W.Mdtrn Sea
    I didn't, but I see you did try get out of the mess what was in your post :D

    You cannot get high CNR/SNR if your RF level is low, the noise floor will not allow to do that.
    Just say you posted being in rush. ;) We will understand that. Making additional noise will not change law of physics.
     
  15. peds48

    peds48 DIRECTV A-Team DBSTalk Club

    18,431
    913
    Jan 10, 2008
    NY
    I fully understand what you are saying VOS, the point I was trying to make however was that a receiver with low RF signal (too any splitters, too long cable run, etc) is more likely to "fade" [(first than the one with higher RF signal) (even if both receivers have the same transponders numbers)] due "atmospheric" conditions, be it rain, extreme heat... as these can cause signal attenuation.
     
  16. P Smith

    P Smith Mr. FixAnything

    21,337
    127
    Jul 25, 2002
    W.Mdtrn Sea
    You still don't get it or still try to make it up ...

    CNR/SNR (e.g. signal level on screen) cannot be high (in 90s) if RF is low; because of existing noise floor (very high in case of SWiM signal) and close relation between all the number.
     
  17. veryoldschool

    veryoldschool Lifetime Achiever DBSTalk Club

    42,649
    338
    Dec 9, 2006
    "If you say within the loss range", this isn't a problem.

    Now I can mockup a setup that would be like what you're saying.
    Step 1: exceed the recommended loss from a LNB to the SWiM [8 or 16]
    Step 2: have a very long run to a receiver.

    "Good weather" will have the SWiM AGC compensate for the "excessive" LNB to SWiM loss.
    As the signals weaken, the longer run can drop below min due to the AGC running out of range, while a receiver on a shorter run may not.

    With a SWiMLNB you can't, because the "weak link" is the loss between the LNB & SWiM.

    The LNB to SWiM loss really needs to be addressed when you feed more than one SWiM or have to locate the SWiM farther from the dish than the 45' recommended.
     
  18. veryoldschool

    veryoldschool Lifetime Achiever DBSTalk Club

    42,649
    338
    Dec 9, 2006
    While the SWiM does look to add some noise, the LNB is also very noisy.

    I'd say Peds is looking at a poor setup like I posted above.

    In "Good Weather" the receiver with a very long run [high loss] has a good CNR, but as the signal drops, while the CNR doesn't, the input level drops below min for the receiver to pickup the CNR, because the SWiM's AGC in limiting.

    "Rainfade" is still at/in the LNB, but the losses between the LNB & SWiM & receiver all need to be within range.

    "Roughly" 5 dB between LNB & SWiM and 30 dB between SWiM and receiver. If within these there isn't anything more that can be done.
     
  19. peds48

    peds48 DIRECTV A-Team DBSTalk Club

    18,431
    913
    Jan 10, 2008
    NY
    Now that is something I was not aware of. so DirecTV recommends that the SWM (8 or 16) not be more than 45 feet "away" from the LNB. I haven't yet "played" with "numbers" coming from the LNB to the switch. I just "played" with the "numbers" coming out of the switch.

    Now that I have your attention let me ask you some Qs (if you dont mind)

    what is the insertion loss of the SWM16?
    Legacy LNBs output about -30dB, does the AGC on the SWM switch compensates for the insertion of the SWM switch?
    I have noticed that the "newer" SWM LNBs are outputting around -21dB, has DirecTV increased the output to compensate loss due to splitters, cable runs?
     
  20. veryoldschool

    veryoldschool Lifetime Achiever DBSTalk Club

    42,649
    338
    Dec 9, 2006
    A SWiM-16 doesn't really have insertion loss.
    It will attenuate any input above -30 dBm and amplify -45 dBm to the -30 dBm output level.
    Legacy LNBs "can be" above -20 dBm, so that's why the -15 dBm upper range.
    It's been a year or so since I tested, but the "-30 dBm" output was measured at -27.
    I haven't [yet] seen -21 dBm output on a SWiM, but it would allow for more loss than before and DirecTV's "cure" most of the time is to add another 2-way off an 8-way so 6 more dB would be a good thing.

    You should have "full range" as long as the SWiM input is at least -30 dBm.
     

Share This Page