HR10-250 OTA signal meters

Discussion in 'DirecTV TiVo Powered PVRs & Receivers' started by oldguy, Jan 20, 2006.

  1. oldguy

    oldguy New Member

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    Feb 10, 2005

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    The OTA signal meters on the HR10-250 show bars for ant in tuner 1 and ant in tuner 2, although there is only one antenna connection.

    With only one antenna, how come there is often 2 different signal levels shown? Also, when tuned to a channel, are both tuners signal for the same channel?

    On my tuner it is usually the 2nd tuner that shows the lower signal when they are different
     
  2. JimSpence

    JimSpence Just hangin'

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    All tuners are not created equal, nor are the splitters used internally in the HR10-250.
     
  3. ebonovic

    ebonovic has gone his way...

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    Tinley...
    There is an internal splitter for the OTA.
    If there is a DRASTIC difference between the two levels (more then 5 points). You probably have a faulty splitter.

    During "testing", yes both tuners are looking at the same frequency.
    After that, each tuner is independent. (there are scerios where they can be tuned to the same frequency... though and that is normal)
     
  4. oldguy

    oldguy New Member

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    Feb 10, 2005
    I understand what you are saying, but if it were a faulty splitter or tuner, wouldn't the faulty one always be lower than the good one.
    Like I say, other channels are almost always equal to each other.

    And, the problem comes and goes.

    Boy, not only did D* make the HR10-250 inferior to others products, they made it confusing.

    Thanks for the reply.
     
  5. ebonovic

    ebonovic has gone his way...

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    Tinley...

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    Huh... my original reply didn't make it...
    EDIT: Ahh... you cross posted...
    http://www.tivocommunity.com/tivo-vb/showthread.php?t=282983

    ------------------
    Anyway... there is an internal splitter on the inside...
    After it LEAVES the splitter, the signal is on it's own... there have been many of cases "the split" causes a MAJOR difference in signal strength.

    During TESTING of the signal strenght, both meters tune to the same frequency.

    During normal ususage.. 95% each individual tuner tunes to a different channel (or signal completely).

    There are cases where the internal splitter has hardware problems. (if you are seeing a difference in multiple points).

    Also you need to understand a little more what that meeter is telling you... Most of the time it is telling you the ralation of errors (or lack of errors) in the signal. Thus, at that split momement the system is checking the "signal" it could be fractionally different then the other.

    Why EACH channel isn't the same... because they are on different frequency and each frequency is affected by the surroundings differently. VHF-3 takes a beating from the Microwave, while UHF-32 could care less.
     
  6. ebonovic

    ebonovic has gone his way...

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    Jul 24, 2001
    Tinley...
  7. ebonovic

    ebonovic has gone his way...

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    Jul 24, 2001
    Tinley...
    To build on the followup you had in the SD forum...


    What specific FREQUENCY is giving you problems.

    If you look at my unit for VHF-3 (WBBM-DT in Chicago)
    When I having SIGNAL issues... I can have 90 on one, 15 on the other, then it flips, then they are both 0, then 30/30, then 85/16, 20/80

    That is a sign of a BAD signal... especially if it is not happening on other channels.

    The tuners for OTA (and I beleive SAT as well) are showing the results of a mathmatic formula based on error/correction ratios... So for fractions of a time, they can be fine, but the next nope... and so on... and the slight difference in electronic delay can account for difference between the two tuners.
     
  8. oldguy

    oldguy New Member

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    Feb 10, 2005
    13 is the specific frequency.

    I apologize for doubting what you said. I finally got the two tuners tuned to the same channel and then used the live tv button to switch between the two. One would pixillate all the time; the other - a stable picture.

    I remembered my electronics and tuners and, yes a tuner can have problems with specific frequencies.

    Is there any easy way to tell what tuner you are using?

    Thanks again for the help.
     
  9. oldguy

    oldguy New Member

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    Feb 10, 2005
    Some time back, I lucked out and found the 888- number that gets you through to the D* Idaho CSR group.

    This group is FANTASTIC!

    They speak English (not pidgen, Phillipino broken english).

    They give you straight answers and, if they don't know the answer, they tell you flat out, "I don't know" instead of trying to blow smoke up your ass. Then they will get you on the phone with a higher level tech if necessary (the other CSR's would often tell you they would put in a trouble report and someone would call you back. HA!

    I can't say enough abouth the Idaho group. Today was my 5th call to them about different problems and each time I was treated really courteously.

    Maybe D* is FINALLY getting their act together???

    BTW, I am going to be selfish and not give out the number because once everyone finds out there IS a place they can get help from D*, the line would be busy all the time.
     
  10. oldguy

    oldguy New Member

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    Feb 10, 2005
    Thanks again for your responses. They helped me figure out a work around for my problem until my replacement receiver arrives.

    When I tune to the problem channel and check the signal level, like you say each tuner tunes to that channel. I then return to viewing using the live TV button and then press the live tv button to toggle the tuners (still set to the problem frequency) and lo and behold one of the pictures will be rock solid.

    Thanks again for a nice, lucid answer and not a crap answer like I got from another person.
     
  11. newsposter

    newsposter Poster of News

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    Some on this board might say that's a one way flow of information, frown on it, and maybe you should have just kept the existance of such a number secret so that men in black suburbans dont come to your house and try to get it :)
     
  12. oldguy

    oldguy New Member

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    Feb 10, 2005
    That's a minor thing. They are already after me for my Google searches. Sometime back I meant to search for "I'm kidding about porn" and somehow some characters got droppped.

    Almost like yelling "Hi, Jack" to a friend on a plane.

    Hmmm, now they'll probably send Homeland Security because of this exchange.
     
  13. oldguy

    oldguy New Member

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    Feb 10, 2005
    BTW, you,too can find the number by searching for Idaho in the D* forums (I can't remember which). it may come up something like 800-739-4388.
     
  14. TyroneShoes

    TyroneShoes HD evangelist

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    Sep 6, 2004
    And this means that the signal carrier power levels may be the same while the success of failure of the ratio of decoded packets may be different (which is what is indicated) on different output paths, possibly due to a reflection or other issue regarding the RF path internal to the HR10.

    A little more about that path: The HR10 does not have a "splitter" in the term generally understood, which would be a passive hybrid-type power divider, which is commonly referred to as an RF splitter. The HR10 contains an active unit that reamplifies a single input signal and distributes it into two output paths. It is more akin to a distribution amplifier and may provide additional active selectivity prior to each demodulator front end, and maybe even heterodyne conversion as part of demodulation. IOW, the two outputs may not be identical while on non-identical channels, and one output should be buffered from the other preventing unwanted interaction. While it performs a similar type of task, that makes it technically very different from a hybrid splitter.

    That being said, if everything were working the way it should, one would think that identical channels would still give identical output readings.
     
  15. bd8201

    bd8201 New Member

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    Oct 25, 2006
    Boston Area
    Does anyone know the units on the Series Signal Strenght Meter? Is it dBmV, or something else? I have a 4 way splitter and get breakup at at a signal of 75 or so. Hooking up the Series 3 directly the Comcast cable signal is fine a 92 or so out to 800MHz, but with a strange drop between 620 and 690 MHz. It's at a minimum of 78 at 650MHz, which is where the ESPN HD channels are in the Boston area. The -14 drop represents 1/25 the of the signal if the meter is the logarithmic dB scale. My cable modem reads -6dBmv at 692 MHz. A Comcast tech is coming out tomorrow to look into the situation.
     
  16. TyroneShoes

    TyroneShoes HD evangelist

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    Sep 6, 2004
    10 months have passed, and we know a little more about the RFDA module in the HR10, including that it does no heterodyne conversion. Folks have occasionally had success bypassing it altogether with a conventional splitter, which proves that. Also there have been a lot of cases of the wiring from the RFDA to the tuners where the connections were loose. Exercising those RCA connectors has fixed problems on occasion. Some of the cases of success in bypassing the RFDA may be purely due to the added attenuation involved, so before attempting a bypass one should try outboard attenuation first, to see if that helps.

    The readings are not signal level readings, they are signal quality readings. Level is secondary to digital reception, unlike in analog reception. Strong signals as well as weak signals can have identical SQR readings, and can both result in perfect reception. Digital is all about decoding success, which is based on how many uncorrupted bits are available. The SQR factors in carrier level, noise, and interference to come up with a quantifiable reading, but there is no direct correlation to carrier level alone. And in fact it does not measure any of those three components directly, just the final result of what those three factors do to reception.

    What that all means is if you have a low SQR there is no way to interpret that directly as a poor signal level problem, an interference problem, or a noise floor level problem. You have to look at the situation and make general adjustments to the level based on the location, signal strength, and antenna system, and adjust accordingly to get the proper levels and noise performance, and you should concentrate on placement and directionality (and possibly filtering, like with an FM trap) to improve the interference ratio. Any or all of those will ultimately improve the SQR, and reception.

    Most true signal level meters measure in dBmV. If you have a true SLM available, 8VSB signals need to be 15 dB above noise to achieve digital lock. Urban noise floor measurements are typically about -29 dBmV, meaning that a dBmV reading of -14 would be the minimum signal needed. In practice a -10 would be more in the area of continued reliability. Well above that is suggested, though, and a 0 to +5 should be plenty.

    If you get too high, the SQR will actually start to go down, as clipping will begin to corrupt more of the bits. The HR10 does not like high signal levels, and will not decode consistently in the presence of high signal levels, so try to keep the strongest signals under +8 to +10.

    Now a "ComCast guy coming" would imply a CATV situation, which is very different from OTA. You need a +1 to a +5 for NTSC channels to typically make their STB perform properly, and the digital channels are QAM, which is an entirely different situation.

    I am only guessing, but I believe the metering in the S3 is again SQR metering. I would also assume that it is designed to operate in the same range as a CATV STB, so if the Comcast tech sees levels that he would like to see on their STB, those levels should also be proper for the S3. Those techs should be able to measure raw signal level and the digital SQR, as well as S/N ratio (which should be at least +20 to +30 dB). If the S/N and carrier levels measure good and you still have a low SQR, that leaves interference as the lone culprit, by default.
     

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