Antenna signal strength question

Discussion in 'TiVo Roamio DVRs' started by lmacmil, Mar 19, 2016.

  1. MikeBear

    MikeBear Letting my mind wander, luring it back with candy.

    436
    123
    May 21, 2015
    Mid-Michigan
    The CM-7777 preamp will WIPE out your signal if you have more than 1 real strong station. It overloads very easy, as it's for extreme far-fringe use. Also, not all splitters pass power. So if your 7777 power injector is on the wrong side of the splitter, your 7777 preamp is not getting power, and is now a 30db ATTENUATOR. Try without it, and going straight to your Tivo. Report back if your signal levels are better. If that antenna is inside your house, that will also cut way down on your signal.
     
    Last edited: Apr 20, 2017
    ClearToLand likes this.
  2. jfj1153

    jfj1153 New Member

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    Apr 12, 2017
    Disconnected the 7777 and and made sure the antenna was at 144 degrees (S/W) I now receive 51 channels on the tivo. It was strange on a couple of channel it showed 85 on the signal strength but I got no picture. So right now everything is fine and I am at least getting some channels.
     
    MikeBear likes this.
  3. ClearToLand

    ClearToLand Old !*#$% Tinkerer!

    1,058
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    Jul 9, 2001
    Central Jersey
    The OP didn't originally mention and preamp so it's good to come back to this thread and find that the problem was so easily solved. :thumbsup:
    • By "WIPE out", do you mean the AGC will just turn way down to accommodate the strong signal at the expense of 'burying' the weaker ones?
      .
    • Is it safe to assume that *ALL* splitters not explicitly marked to pass power don't?
      .
      I have a 'yet-to-install-in-my-attic' Antennacraft HBU33 (70 miles VHF, 60 miles UHF, towers 24 miles away) along with a Winegard AP-8275 and 10db, 6db, 3.5db (2-way splitter w/ 75 ohm terminator) attenuators to 'fine tune' the signal if necessary. I have ~50 ft of 40+ year old RG-59 (always indoors) running from my attic to my basement 'control room' (i.e. all tv and telephone lines converge here) and I have (up to) 14 ATSC devices to feed. I think I'm good. Do you see any potential problems?

      Upon re-reading this entire thread, I found this interesting post:
      I have 3 SiliconDust HDHDR3-US tuners, and until the HBU33 gets installed (after my surgery) I have just a Philips SDV2210/17 (Rabbit ears w/ UHF loop) to play with in testing out my (sorta new) Roamio OTA. Initially, after a bit of finessing with the ear length, angle, and '12 Position Fine Tuning' knob, I was able to get the closest local VHF PBS station (RF Channel 8, 6 miles at 301°) located on a small hill (with the antenna balanced on the lamp shade of the lamp on the tall bureau). Then one day it fell, I tried to get the picture back, played with the '12 Position Fine Tuning' knob (shouldn't have touched it) and now nada. It doesn't seem to me that it should be that difficult to receive:
      In comparison, WABC @ 22 miles, which originally just popped in-and-out, has MUCH less power:
      • Callsign: WABC-TV
      • ERP: 3.2 kW
      • HAAT: 491m
      • MHZ: 180

      Where am I going?

      Well, what do you have in your personal 'Bag of Knowledge' regarding the relationship between:
      1. Signal Strength
      2. Signal Quality
      3. Symbol Quality

      I've moved the 'ears' from fully horizontal to 45°, changed their lengths from 63.48" 'tip-to-tip' to 31.74" each. The SD display is encouraging so soon after I post this I'm going to grab a HDHR3-US from the living room (connected to FiOS cable for Clear QAM for WMC) and see what results I get with the Philips.

      Growing up in NYC, almost every relative and friend of my parents that we visited had Rabbit Ears (transmitting antennas were first on the Empire State Building, then the World Trade Center). UHF tuners weren't even invented yet so it was channels 2-13 VHF for everyone.

      Currently, I'm only 'aware' of #1, Signal Strength. I have a suspicion that #2 and #3 will shortly expand my knowledge of ATSC signal reception.

      Thanks in advance for any guidance. :)
     
  4. ClearToLand

    ClearToLand Old !*#$% Tinkerer!

    1,058
    155
    Jul 9, 2001
    Central Jersey
    SiliconDust HDHomeRun Config GUI:
    [​IMG]
    Yay!!!
    It was that darn '12 Position Fine Tuning' knob that got me - although I always had ~95-100% Signal Strength, I had 0% Symbol Quality due to ~42% Signal Quality (Yellow didn't show up too well).

    Right now my Roamio OTA is SOLIDLY displaying WNJB with a TiVo Signal Strength of 50 (Peak 55).

    Each 'Rabbit Ear' is 31.75" 'Base-to-Tip', they are completely horizontal, and per my Army/Navy compass, pointed 301°. At ~6 miles (and 20.2 kW), I expected more - but that is an 'Experiment' for another day.

    Some interesting LINKs I found:THANKS @Dixon Butz !!! :thumbsup:

    P.S. From this experience, I'd say to ALL TiVo owners, "Forget about (meaning insert the appropriate curse word) the Signal Strength Meter"!. Further research on @JoeKustra 's posts regarding OTA Signal Strength is on my "ToDo List"...
     
  5. MikeBear

    MikeBear Letting my mind wander, luring it back with candy.

    436
    123
    May 21, 2015
    Mid-Michigan
    My immediate answers in red within your quote above.

    You should repost all this here, and ask Rabbit73 for help. He's REALLY good at all this, and enjoys helping others. You MUST also post your TVfool and FMfool report, as those are critically needed to give you the BEST answers:
    Code:
    http://www.avsforum.com/forum/25-hdtv-technical/
     
  6. JBDragon

    JBDragon Member

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    Jan 3, 2004
    Fairfield, CA
    Did you try the antenna without the Amp? Sometimes with strong signals, putting a amp on will kill the signal. How many times is the cable split? The more the weaker the signal is going to be. How good is the cable? Putting a Antenna in the attic will reduce the distance it can pick up the signal from the signal being blocked some from your roof, and because it's low. Mounted above your takes care of those 2 issues. HOA's suck and I'd never move into one. No group of busy body's is going to tell me what I can and can't do with my own house.

    My TV's have a built in Signal strength meter in them and so I can see how good it is that way. I also have a couple HDHomerun's, one is currently plugged into my antenna and using the app on my iPhone called Signal GH I can have it scan for channels and view the signal strength. I can be on the roof running it to fine tune the antenna direction that way. I can click on Towers and it'll give me a Map along with the grouping of TV station channels on it then using the arrow of my location, turn my phone until it's pointing at the towers and going my how my phone is pointed, I can turn the antenna to match and then fine tune it to get the channels I want by watching the signal strength meter watching a couple channels at once. When you zoom into the map, you can see that not all the stations are really located in the same area, but spread out some. So you may need to fine tune to get kind of in the middle of the group.

    It goes without saying, get a big directional antenna. I ended up getting the Winegard HD8200U from Amazon. Back in Sep 2012 shortly after getting my house late October. The Antenna I have grounded along with the Coax cable I have a grounding block on that and it's all new cable. It's just over 8 feet long.
     
  7. Bucket73521

    Bucket73521 Member

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    5
    Apr 29, 2017
    Looking at tvfool you should be getting all but two with a vhf antenna. Your NM (dB) range 12 to 48. About 25 channels should be at 144°.
     

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