Optimizing over-the-air reception

Discussion in 'TiVo Coffee House - TiVo Discussion' started by Drewster, Dec 2, 2011.

  1. Dec 2, 2011 #1 of 13
    Drewster

    Drewster Connoisseur

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    Hi all,

    I need advice on over-the-air reception.

    Right now I have a single TV (yes, just one) and an FM tuner (stereo receiver), hanging off a coax splitter. I do not anticipate having more than one TV. (We're weird that way.)

    There is a single line of coax to the antenna in the attic. The antenna is nothing special, I bought it cheap several years ago for mainly FM reception. I honestly don't know if it's just FM, or low-VHF, or low+high VHF, etc. As measured by the signal indicator on the TiVo Premier XL, most channels measure in the mid-50s to 70s, and are fine for watching TV. However, channel 7 is particularly bad, often in the 20s and usually unwatchable.

    The cable run from antenna to media cabinet is probably 60-70 feet.

    If I want to improve my general lot but optimize costs, is it better to have a pre-amplifier at the antenna and a splitter at the cabinet? An amplifier/distributor at the cabinet? A better antenna? etc.

    Thanks for suggestions, opinions, etc.
     
  2. Dec 2, 2011 #2 of 13
    Wil

    Wil Unknown Member

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    If you can get a small TV to the antenna attached directly with a short length of cable, and play with the direction of the antenna, and compare that with the same set at your normal location, that difference defines the best you're going to be able to achieve with THAT antenna.

    If it's significantly better at the antenna than at the normal location, a preamp, low noise/low/moderate gain/high quality, that passes whatever you're getting (LVHF/HVHF/UHF/FM), will get you some of that back. A "splitter" that passes all but the FM may lose slightly less TV signal than a wide spectrum splitter.

    A preamp can overload and make the problem worse.

    Having said that, the best amplifier is an antenna, or a set of antennae, that matches the bands you receive and has enough gain for your area. There are websites where you enter your address and it shows you the direction and strength of the channels in your area. Match that data up with a good antenna set. Obviously you have to take into account the attenuation from the roof, much better to get it out of the attic. I'm guessing that channel 7 is in a different direction; you can experiment with finding a sweet spot for pointing that gets you 7 without losing too much of the others. It is also possible to buy a second antenna cut specifically for channel 7 and use an interface box to "cut a hole" for it in the feed from the main antenna. Join-tenna is a product name for one such box.

    With only a 60-70 foot run, you should be good to go with a well matched antenna set, without a preamp.
     
  3. Dec 2, 2011 #3 of 13
    dlfl

    dlfl Cranky old novice

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    The sites for locating stations near your loaction, directions, frequencies etc. are: tvfool.com and antennaweb.org. Both are good and provide very similar info.

    I recommend you use these sites and post some results as to directions, distances and bands (VHF or UHF) of the stations you want to receive. That will help us to help you.

    All the local stations I get with a small directional $20 UHF indoor antenna on the first floor are 10 miles away and give signal strengths of 80 - 98 on my Tivo HD.
     
  4. Dec 2, 2011 #4 of 13
    Aero 1

    Aero 1 Active Member

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    Like dlfl said, go to tvfool.com, enter your address and post the results. It is needed to give you a recommendation.
     
  5. Dec 2, 2011 #5 of 13
    Drewster

    Drewster Connoisseur

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    Here's my output at TVFool.

    ...and my text-formatted output from AntennaWeb:
    Code:
    Antenna Type   Call Sign   Channel  Network  City, State                 Compass Heading    Miles From   RF Channel
    yellow-uhf     KBEH-DT     63.1     ETH      OXNARD, CA                  332*                        37.2         24
    green-uhf      KTBN-DT     40.1     TBN      SANTA ANA, CA               332*                        37.9         33
    green-uhf      KVEA-DT     52.1     TEL      CORONA, CA                  332*                        37.2         39
    red-uhf        KDOC-DT     56.1     IND      ANAHEIM, CA                 332*                        38.1         32
    red-vhf        KCAL-DT     9.1      IND      LOS ANGELES, CA             332*                        38.2          9
    red-uhf        KJLA-DT     57.1     IND      VENTURA, CA                 332*                        38.1         49
    red-uhf        KFTR-DT     46.1     TFA      ONTARIO, CA                 332*                        38.1         29
    red-uhf        KAZA-DT     54.1     AZA      AVALON, CA                  332*                        38.2         47
    red-vhf        KABC-DT     7.1      ABC      LOS ANGELES, CA             332*                        38.2          7
    red-uhf        KSMV-LD     57.1     IND      VENTURA, CA                 332*                        38.1         23
    red-vhf        KCOP-DT     13.1     MNT      LOS ANGELES, CA             332*                          38         13
    red-uhf        KCBS-DT     2.1      CBS      LOS ANGELES, CA             332*                        38.2         43
    red-uhf        KCET-DT     28.1     IND      LOS ANGELES, CA             332*                        37.9         28
    red-uhf        KMEX-DT     34.1     UNI      LOS ANGELES, CA             332*                        38.1         34
    red-uhf        KPXN-DT     30.1     ION      SAN BERNARDINO, CA          332*                        37.1         38
    red-uhf        KRCA-DT     62.1     IND      RIVERSIDE, CA               332*                        37.2         35
    red-vhf        KTTV-DT     11.1     FOX      LOS ANGELES, CA             332*                          38         11
    red-uhf        KWHY-DT     22.1     IND      LOS ANGELES, CA             332*                        37.2         42
    red-uhf        KTLA-DT     5.1      CW       LOS ANGELES, CA             332*                        38.1         31
    red-uhf        KXLA-DT     44.1     IND      RANCHO PALOS VERDES, CA     332*                        38.1         51
    red-uhf        KOCE-DT     50.1     PBS      HUNTINGTON BEACH, CA        332*                        38.1         48
    red-uhf        KLCS-DT     58.1     PBS      LOS ANGELES, CA             332*                        37.9         41
    red-uhf        KSCI-DT     18.1     IND      LONG BEACH, CA              332*                        37.2         18
    red-uhf        KNBC-DT     4.1      NBC      LOS ANGELES, CA             332*                          38         36
    blue-uhf       KEDD-LD     50.1     IND      LOS ANGELES, CA             332*                        38.6         50
    blue-uhf       KTAV-LD     46.1     IND      ALTADENA, CA                332*                        38.1         46
    blue-uhf       KNLA-CD     50       IND      LOS ANGELES, CA             332*                        38.6         50
    blue-uhf       KNET-CA     25       IND      LOS ANGELES, CA             332*                        37.1         25
    blue-uhf       KSGA-LD     57.1     IND      VENTURA, CA                 332*                        38.1         30
    blue-uhf       KVHD-LD     40.1     TBN      GLENDALE, CA                332*                        38.1
    
    
     
  6. Dec 2, 2011 #6 of 13
    dlfl

    dlfl Cranky old novice

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    The good news is they are all in the same direction, which means you benefit from a directional antenna, which will provide better performance for the same size antenna than an omnidirectional one. Channel 7 is a VHF frequency, which inherently requires a larger antenna, with size on the scale of the old rabbit ears fully extended. I would say get a quality dual-band directional antenna preferably in your attic. I can't recommend one from memory but there are threads here where recommendations are given, just search for threads with "antenna" in the topic. I would not go for an amplifier unless nothing else works. You'll have to spend more than $20 given your 38 mile distances. (Mt. Wilson, isn't it?)
     
  7. Dec 2, 2011 #7 of 13
    lrhorer

    lrhorer Active Member

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    To expand on that a bit:

    The purpose of an amplifier is to take a spectrum comprised of signals of good levels and increase their levels before inserting into a cable system in order to overcome the losses in the cable system so the signals are not too low when they reach the receiver. If the levels are too low when they reach their destination, then it is too late and an amplifier placed there won't help much. If signal levels are good at the entenna, but too low after going through the cable system, then a pre-amp may be required. If the levels at the terminus are good without a pre-amp, then no pre-amp is required, but if the cable has to be split at that point, then a distribution amp may be called for in order to prevent the signals from being too low after going through the splitter.

     
  8. Dec 2, 2011 #8 of 13
    Aero 1

    Aero 1 Active Member

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    You need a VHF element to your antenna in order to lock in channel 7. I was in a similar situation so I got an antennas direct clearstream5 VHF antenna and joined it with my UHF antenna with its supplied UHF/VHF combiner.

    The bottom black square part is my clearstream5:

    [​IMG]
     
  9. Dec 5, 2011 #9 of 13
    Drewster

    Drewster Connoisseur

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    So, a funny thing happened over the weekend. I went into the attic to check out my antenna's location. While there I realized that [a] the antenna was *backwards*, off-angle anyway, and [c] one of the leads may have disconnected! (I noticed the disconnected lead while trying to unscrew the F-connector.)

    After fixing all that, the signal strength and picture results are all MUCH better. Go figure. :p

    With these results, I'm just going to get a better antenna. :D
     
  10. Jeff_DML

    Jeff_DML Member

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    darn that thing is expensive but that might be what I need of rmy VHF problem channel. I take it is very directional since high gain? I have multipath problems so need a directional antenna but the usual directional VHF are too big.
     
  11. Aero 1

    Aero 1 Active Member

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    well worth the $90 i paid for it. totally made the 3 VHF stations in my area, fox, cw and abc consistent for me.

    its the smallest and most compact vhf antenna i have ever seen. here are the specs

    http://www.antennasdirect.com/cmss_files/attachmentlibrary/C5_ technical_ data_ with_uhf.pdf
     
  12. Jeff_DML

    Jeff_DML Member

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    Mar 2, 2009
  13. Drewster

    Drewster Connoisseur

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    Interesting. I was thinking of using a UHF/VHF boom-type antenna, the Winegard HD7084. At ~$100 it's seemingly a sweet-spot bargain.

    But a setup like yours would be easier to wrangle in my attic. Hurm.
     

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