Getting intermittent interference, need some input

Discussion in 'Over the Air TV By RabbitEars.Info' started by andy_horton, Oct 20, 2017.

  1. Have both indoor and outdoor antenna. Outdoor is 10 ft up, preamp. UHF 4 bay Channel Master. Indoor is a flat antenna on wall for hi-VHF, with an amp. Tried disconnecting all amps, with amps. Having intermittent interference at the same time on both antennas. Have made sure nothing electrical from at least my end is affecting this. I haven't changed my setup in any way. I did disconnect the A/B switch and plugged each antenna into antenna input into tv and checked signal strength. It reads between 86-100, 94 being the average with 86 being the threshhold, but even at a reading of 94, sometimes it wants to pixelate. Thats the interference I'm referring to. Only thing I have thought of are the heat pumps at night. But then since they also are used for A/C, seems like they would've affected reception then too. Can't figure out where interference is coming from. Again, happens both with and without amps attatched, have removed switch to test, and happens at the same time on both indoor and outdoor antennas. Definitely more pronounced at night, and has just started this past week, when the weather got cooler. Any thoughts? Thanks. Andy
     
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  3. How close is the indoor antenna to the TV and how long is the run to the UHF antenna?

    I'd try running a new, properly terminated cable as a test. If the problem goes away, you have cabling (or connectors) that have failed. Lowes sells a nice pre-fab 100' RG6 quad shield with compression connectors for under $27. They also offer a much less spectacular crimp-type dual shield for under $20. Shorter lengths are cheaper if you can get away with it. Other home improvement, hardware and department stores have their versions of these products.

    If the interference doesn't go away, you have a new source of interference that you didn't have before or the TV itself may be the problem.

    Rain makes things interesting as what used to be insulated by air may now be occupied by water that can be an unpredictable electrolyte.

    As always, make sure you don't have any kinks in the cabling and that any bends that you have are gentle (2" bend radius or greater). Cable that is kinked or crushed will eventually collapse and its transmission properties will be compromised.
     
    andy_horton likes this.
  4. I've went out today and bought new cabling from Lowes. Will try today. Also, indoor antenna is in kitchen, outdoor is on patio. Properly grounded. I'd estimate outdoor to tv is approx 100ft or less. New smart tv. Did make small turn in outdoor antenna last night and has helped signal strength. Hopefully between new wiring and slight turn this clears it up. Thanks for the advice. Andy
     
  5. LED light bulbs, noisy power bricks (laptop, all sorts of various devices), car & lawn tractor battery maintenance chargers in the garage, noisy power pole transformers.

    Just a few mentions that can all cause issues. Try grounding your coax to the house grounding rod. That might help a bit.
     
  6. This sounds a lot kike the effects that multipath interference can produce. You really need to see the waveform on a spectrum analyser to positively identify that as the cause. A good signal has a flat top to the waveform; multipath produces troughs and peaks (a bit like the Rockies!).

    I've seen these symptoms, and they were caused by combining two antennas pointed in different directions (which creates multipath interference). The signal strength was always high, but the signal-to-noise ratio went below 15dB, causing the macro blocking. Removing the connection to one of the antennas immediately solved the problem.
     
  7. You carefully avoided answering my question about the distance to the indoor antenna.
    If you were getting signals in the 90s before, this doesn't seem to be a reasonable expectation.

    There's a bit of a conflict in your statement about your layout. The implication is that you're using an AB switch but you mentioned that you're having the problem on both antennas at "the same time".

    You have to be extra careful when providing the setup details. It can't be both ways but if it appears to be, someone (such as myself) will go into a spin trying to reconcile.
     
    primestar31 likes this.
  8. It's always amazed me when people ask for help on OTA on many sites, and then most times you have to PULL all the info out of them with post after post before you get enough to figure out what's going on.
     
  9. If the TS is using amps and a four-bay, multipath isn't the first thing I'd jump at. Of course since the antenna apparently wasn't aimed optimally, all bets are off.

    UHF doesn't bounce much and it certainly doesn't travel well.
     
  10. This comes from not knowing what is important and that's to be expected with something that is almost a "lost art".

    It is also a problem that people chime in with red herrings, distractions, me-toos or authoritative information given out without the background motivation to make sense of it.

    The key in solving most any problem is understanding where you're starting and where you want to go. A bigger problem is when someone starts in the middle with what has failed thus far and assumes that we know both the start and the desired result.

    As the repack progresses, it seems almost likely that we're going to see some real interference as a result of testing of new channels in adjacent markets.
     
  11. Antenna in the kitchen, 2nd antenna on patio sounds like a first floor apartment..
     
  12. I asked for a distance and got a inconclusive room reference. Even if the TV is in the kitchen, that's still not something that substitutes for a distance.

    Distances in the context of downleads and cable runs should be in wire feet. Part of my goal in obtaining this length was to assess if there were any couplers or chances for the cable to pass through things that might compromise the cable. The other side is how much loss there might be as some indoor antennas use relatively high-loss cable and using that cable with a different kind of cable can lead to reflections within the cables.
     
  13. My indoor antenna on the wall for hi-VHF is because I CANNOT get signals in the living room. NO MORE THAN 50 FT!! I wasn't trying to avoid your question. The cable is run from kitchen to the A/B switch right around the corner to living room. It is amplified. The outdoor is a little farther on patio, 10ft up, guesstimate 50 ft in with a preamp. Since the post I have not had the interference. I simply needed help. I in NO way tried to evade the question. Why would I do that? It does no good if I don't relay all info. If I missed something, so sorry. Does this help you?
     
  14. I live in a 1 bedroom house with a metal roof...makes for HORRIBLE reception indoors!!
     
  15. I'm just looking for some help. Came here because I've been on this site for years. I would appreciate CONSTRUCTIVE help instead of a reply like this. Not everyone is as "well versed" as "some" people seem to be here obviously
     
  16. Andy, I'm not trying to target you or pick on you or anything like that. I'm just pointing out that many people (not just you) just never seem to give enough info to help right off the bat. So, we are left just repeating all generic info and hoping something helps. Other people that also need help might read this thread, see my post, and then realize they need to give just a little more info up front, that's all.

    Fixing issues like this with digital tv is more black magic than anything else. Every situation is fairly unique, and needs to be thought about carefully. The more info the better for us to help.
     
    danristheman likes this.
  17. I understand that you're having problems but to get help, you have to give details. You opened with the fact that you were having problems with "interference" and made mention of what your outdoor antenna was and that you had a second indoor antenna. No details about cable type, cable length, how many couplers were in use. These are the things that we have to know.

    When I asked how long the indoor cable was you said "in the kitchen". Since you didn't tell us where the TV was (after a subsequent response, now we know the TV is in the living room a relatively long distance away) and how that related to where the kitchen was, you didn't address my question. It was like asking "what time is it" and you answer "Wednesday".

    Now that the run lengths are known, it would be useful to know how many couplers are in play, what the indoor antenna is (rabbit ears, mud flap, mini-Yagi) and how it is cabled. Every coupler subtracts from the signal and brings an opportunity for reflections that may be causing your problems. If a cable gets pinched anywhere, that can also introduce interference through reflections within the cable.

    Then there's the possibility that your interference is coming from some outside source that is not within your control and only moving the antenna(s) around might get away from it.
     
    primestar31 likes this.
  18. That metal roof is an important piece of information especially with an indoor antenna.
     
  19. That depends on the style of the indoor antenna and we don't have that information.

    In any event, since it was happening with both antennas, it seems more like an electrical issue or perhaps the TV itself.

    Alas, since the system isn't showing symptoms anymore, testing of theories isn't really possible but verification of contributing issues like damaged cable or loose connections is certainly doable.
     
  20. Thanks for the understanding. To clarify, and I guess why I the length of cable and what not was so vague is because I'm just used to being able to "tinker" with my setup and honestly wasnt thinking of length or what have you, the run for the indoor is roughly 25-30ft. I'll give more detail to help you. It's an "Amazon Special" flat indoor with that very "thin" wire..meaning I can move the wire on the floor to the Mohu amp I have connected, that's about a total of 10 ft, then to a coupler, which then runs the other I'd say 10-15ft into A/B switch, then to tv. It's a flat antenna. Outdoor has the preamp from about a 5 ft wire, to the input, then i to house via backdoor straight to the power injector, then to A/B switch, then to tv. Actually that antenna is the 4 bay UHF and gets hi-VHF actual channels 9 and 13 (shows up channel 3 on tv.) 12 doesn't come in on that. But what I was really trying to figure out was the interference happens the same time just on the hi-VHF channels at the same time when it occurs. Most times at night. Today it has occured around 5pm. Not really happening on the UHF channels. I've tried plugging both coax lines directly into tv and taken A/B switch out of equation. Also tried without any amps or preamps. All signals are too weak at that point. I get horrible pixelation without the amps. On my smart tv, if the signal drops below 74, it starts that. Usually even when interference is occuring, for the most part I'm getting about 94%. Unfortunately, no bar to show spikes with lowest number and highest, just expressed in current %. When the wind blows hard, it does make a difference. I trimmed and cut a lot of limbs that were in LOS of outdoor antenna and it made a big difference. Still having some issues again with this. The small Mohu amp ks plugged into a power strip, tried another outlet, bad pixelation on indoor antenna. Nothing else in power strip. Wineguard power injector plugged into outlet. Have eliminated any source like microwave, coffee pot, lights, can opener, kinda baffled. Maybe winds, as I have a metal roof and even on outdoor antenna since it's only 10ft up? Thanks for the understanding and I hope this helps.
     
  21. Hello. I've since added what I think is much more helpful info in an added post. Sorry for any inconvenience and I hope my new lost does help
     
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