Testing Splitters

Discussion in 'DIRECTV - SWMLine Discussion (private)' started by Coffey77, Apr 15, 2008.

  1. Mike Bertelson

    Mike Bertelson 6EQUJ5 WOW! Staff Member Super Moderator DBSTalk Club

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    My first sip was at 4:30am this morning...fresh ground Costa Rician Peaberry...:coffee

    Questions:

    1. Do all the receivers communicate via the same "9th" channel?
    2. If there are 8 channels equating to 8 tuners, how does each receiver know which channel is theirs?
    3. Does this also imply that the SWM5 has a 6th channel reserved for receiver communication?
    Mike
     
  2. veryoldschool

    veryoldschool Lifetime Achiever Staff Member Super Moderator DBSTalk Club

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    1) they communicate through the "LF" [2.3 MHz].
    2) they must be "told" and [again] should be the 2.3 MHz "com line"
    3) The SWM5 would have "6" [not counting the 2.3 MHz] for guide info "sharing".

    In a "non SWM" there are four guide data tps, so the data is always accessible.
    With SWM, these four are not available, so it needs to have its own "channel".
    So:
    one LF frequency for "comm".
    5 or 8 channels for the tuners
    1 channel shared for constant guide updating.
     
  3. Mike Bertelson

    Mike Bertelson 6EQUJ5 WOW! Staff Member Super Moderator DBSTalk Club

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    What does "LF" stand for?

    Mike
     
  4. veryoldschool

    veryoldschool Lifetime Achiever Staff Member Super Moderator DBSTalk Club

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    [second cup of coffee] "low Frequency" is my guess [aka 2.3 MHz]
     
  5. Mike Bertelson

    Mike Bertelson 6EQUJ5 WOW! Staff Member Super Moderator DBSTalk Club

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    Sorry..should have guessed that...:rolleyes:

    A little too quick on the reply button.....

    Mike
     
  6. jmschnur

    jmschnur Icon

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    SKYwalker 23502 single power pass between the PI and the LNB is working fine so far.
     
  7. NR4P

    NR4P Dad

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    I found the LF signal. It's actually centered at 2.340 Mhz.
    On a radio with AM, FM or SSB detection, its a pulsating sound at an interval of about .5 secs.

    My antenna is about 25' from the LNB and for those that understand RF, its +40db over S9 (with a non-resonant ant at the freq.) I am surprised how strong it is and I assume the LNB is radiating the signal.
     
  8. SFNSXguy

    SFNSXguy EOE

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    Wonder how the good 'ol FCC feels about that....
     
  9. NR4P

    NR4P Dad

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    I wouldn't jump to any conclusions. The antenna is 25' away. If I had a mobile receiver and antenna then I could test the radiation better. It could still meet Part 15.
     
  10. jmschnur

    jmschnur Icon

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    Is the LF signal strong enough to get into the fornt end of your receivers?

    Joel
     
  11. veryoldschool

    veryoldschool Lifetime Achiever Staff Member Super Moderator DBSTalk Club

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    I think it comes from the front end of your receiver, since it needs to "tell" the SWM what channel it wants.
     
  12. jmschnur

    jmschnur Icon

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    I was wondering if this sginal could leak into other non DTV electornic boxes to cause interference.

    Joel
     
  13. veryoldschool

    veryoldschool Lifetime Achiever Staff Member Super Moderator DBSTalk Club

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    2.3 MHz shouldn't be a "big deal". There are so many signals "down there".
     
  14. NR4P

    NR4P Dad

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    The questions motivated me to try some things.
    First unplugged all receivers. No power to any. The only power was the PI and the signal was still there, but down about 40db (S9).

    Plugged in the receiver closest to the antenna, and the level didn't change until the "almost done" appeared on Step 1 of 2. It jumped up 10db at that point.

    Then as I plugged in each receiver (one quite far away), the strength and pulsing rate climbed. As VOS says, it comes from the receiver. At times the pulsing was many times per second and others, about once per second. But the highest strength was when all 3 receivers were powered up to at least step 2 of 2.
     
  15. smiddy

    smiddy Tain't ogre til its ogre

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    My Splitter is a:

    Manufacturer: Radio Shack
    Part Number: 16-2570
    Frequency: 40 - 2150 MHz
    Notes: DC passing to main input. The packaging specifically says Satellite 4 - Way Splitter.

    Attached is my setup:
     

    Attached Files:

  16. smiddy

    smiddy Tain't ogre til its ogre

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    On the SVI, do you know if it is specified as power passing and what is the freq range?
     
  17. smiddy

    smiddy Tain't ogre til its ogre

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    Is this on both or just one, the terminations needed? I assume that both fail if you have an open port, is that correct?
     
  18. RobertE

    RobertE Active Member

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    The SVI is 5-2300, doesn't say about power passing. It does say diode protected.
     
  19. bakers12

    bakers12 ΔS > 0

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    Diode protected means it's designed to let power pass only in the correct direction. No stray DC voltages can come back up the wrong line to damage something.
     
  20. Coffey77

    Coffey77 Cutting Edge: ECHELON '07

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    Thanks! Updated a few notes and links - sorry for the delay. Busy start to summer. :)
     

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