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  • Television Signal Interference

    Has anyone looked into the TV antenna booster interference when the kitchen or bathroom fans are on?

  • #2
    Originally posted by MidwestCamper View Post
    Has anyone looked into the TV antenna booster interference when the kitchen or bathroom fans are on?
    Hi Jim,

    This is definitely a recognized issue. It can even happen with some types of LED bulbs and dimmers. The over-the-air TV antenna reception is very susceptible to interference. A lot depends on the strength of the TV station signal and its direction. If a weak signal is coming past the fan to get to the antenna and you turn the fan on, it will cut out the signal. If the signal is stronger and from a different direction the fan will not affect it. Sometimes the fan will cut out the signal if we have two TVs on, but not if we have only one TV on. We see every combination of the above when we are on our long term site in Florida, receiving TV stations from Tampa or Orlando, each about 50 miles away in different directions.

    If anyone knows of a better/stronger booster . . . I would be interested in that .


    Rob
    Last edited by Cate&Rob; 09-24-2019, 02:00 PM.
    Cate & Rob
    (with Border Collies Molly & Angel + Kitties Hazel & Elsie)
    2015 Reflection 303RLS
    2022 F350 Diesel CC SB SRW Lariat
    Bayham, Ontario, Canada

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    • #3
      Originally posted by Cate&Rob View Post

      Hi Jim,

      This is definitely a recognized issue. It can even happen with some types of LED bulbs and dimmers. The over-the-air TV antenna reception is very susceptible to interference. A lot depends on the strength of the TV station signal and its direction. If a weak signal is coming past the fan to get to the antenna and you turn the fan on, it will cut out the signal. If the signal is stronger and from a different direction the fan will not affect it. Sometimes the fan will cut out the signal if we have two TVs on, but not if we have only one TV on. We see every combination of the above when we are on our long term site in Florida, receiving TV stations from Tampa or Orlando, each about 50 miles away in different directions.

      If anyone knows of a better/stronger booster . . . I would be interested in that .


      Rob
      Rob,

      Thanks for the info. Two solutions come to mind. First might be to move to a brushless PC type fan or the second, is to possibly make up a filter. An EE buddy will be looking this over and take some measurements.

      Right now I have to look into a larger issue where my main 12V type one breaker kept opening the circuit on a return trip last week. Noticed this since my camera would stop working. So I will be looking to see if this is possibly due to wire chafing while in motion. There are no issues while sitting stationary so this could become interesting.

      Jim

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      • #4
        I have a couple of the fan motors at home from the OEM ceiling vent and from the outside frig fans.
        Vent fan motors are DC Motors with Brushes, Ventline PN VD0218-00, 13.6V, 1.2A.
        The frig fan motors are DC Brushless Motors, M# RDM1238B, 12V, .40A
        Hooked up to a 12V battery and o'scope can see the noise signals they make.
        O'scope measurement scale was set to 100mV/Division, so each horizontal graticule mark on the scope is 100 milli volts of voltage.
        Added a filter for automotive use to see if the noise is reduced.

        Vent Fan direct to battery:


        Vent Fan after noise filter:


        Frig Fan to direct battery:


        Frig Fan after noise filter:
        Last edited by gbkims; 09-25-2019, 06:48 PM.
        Gene and Kim
        2015 Grand Design Reflection 317RST
        2017 RAM 3500 CC, LB, 4x2, 6.7L CTD

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        • #5
          Gene

          Being as I am not electrically inclined could you determine, by your testing , that a filter would be beneficial?
          If so , Would you have one that you would recommend? Something we home owners could install easily.

          Thanks
          Brian

          PS: I love the technology base that is available here with just a question.
          Brian & Michelle
          2018 Reflection 29RS
          2022 Chevy 3500HD

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          • #6
            Originally posted by gbkims View Post
            I have a couple of the fan motors at home from the OEM ceiling vent and from the outside frig fans.
            Vent fan motors are DC Motors with Brushes, Ventline PN VD0218-00, 13.6V, 1.2A.
            The frig fan motors are DC Brushless Motors, M# RDM1238B, 12V, .40A
            Hooked up to a 12V battery and o'scope can see the noise signals they make.
            O'scope measurement scale was set to 100mV/Division, so each horizontal graticule mark on the scope is 100 milli volts of voltage.
            Added a filter for automotive use to see if the noise is reduced.

            Vent Fan to battery:


            Vent Fan after noise filter:


            Frig Fan to battery:


            Frig Fan after noise filter:
            gbkims,

            This is fabulous! Now for the question: Did you buy a filter or make one? You stated automotive filter, can you provide a part number and vendor?

            We were planning on scoping these signals and to perform an FFT and build a filter for the offensive frequency response. But a brushless fan and/or a store bought filter will save us time.

            Jim
            Last edited by Guest; 09-25-2019, 04:33 PM.

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            • #7
              This quick and dirty test was just at the house with the motors out of the rig.
              I had a filter on hand that was for my truck, it's the type for reducing noise in audio or cameras. PAC CSS12 Passive Noise Filter, 12 Amp, Choke and Capacitor Design.
              It's has 2 capacitors and an inductive choke in it.
              I did see a reduction (attenuation) of the noise the motors generate on the battery side of the filter.
              I had scoped these motors awhile back and just tried a small value capacitor .001uf across the motor's +12V, -12V wires, no effect on the noise.
              The filter has 3 wires, one for -12V, and +12V In and Out. It's placed in series between the 12V battery and motor(s).

              Don't know if this filter would work for the television interference. I'm guessing the noise is going into the antenna ampifier via the +12 booster.
              I do wonder if the frig brushless motors cause less interference with the television signals, or if it's because they are farther away form the antenna amplifier.
              I sort of recall that television signal voltages into the input of the television is in the 1 millivolt range, pretty small, so easy for noise to swamp the signal.
              Gene and Kim
              2015 Grand Design Reflection 317RST
              2017 RAM 3500 CC, LB, 4x2, 6.7L CTD

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              • #8
                Gene,

                I think for the price it would be worth purchasing the filter and installing it on the 12V feed to the booster. I'll speak with my EE buddy on audio versus video frequencies to see if this makes sense. If this does not give us the right attenuation we will plan on doing some work on this. My background gives me some knowledge in this area since I did spark knock control years ago to find the knock frequencies on high performance engines. Using signal to noise principals we could do many things to detect this signal but in this case, we want to eliminate the signal coming from the fans. I will need to tap into my buddies EE background for equipment and to build a filter if this is needed.

                I believe the brushless motors would be better for interference than a brushed motor.

                Thanks a bunch for such great work.

                Jim
                Last edited by Guest; 09-25-2019, 07:12 PM.

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                • #9
                  I believe my loss of power issue has been solved. Looks like its the main switch. Turn it on and barely touch it in the off direction and it opens the circuit. I'll call GDRV today in how to get a replacement switch.

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                  • #10
                    Took a few readings at the rig today. I did see my OEM bathroom fan puts out the same noise as the ones I have at home.
                    Didn't have any television picture interference with the hall maxxfan and bathroom OEM fan on.
                    Took the readings at the fuse 4 on the panel. It feeds power to the hallway & bathroom fans and then to the antenna booster. Didn't check at the booster b/c it's a pain to pull out of the ceiling.
                    Took one reading right on the bathroom fan motor terminals with it on.

                    Fuse Panel - no loads, 50mV scale


                    Fuse Panel - Ceiling, Island, Hallway, Bathroom Lights ON, 50mV scale


                    Fuse Panel - Lights ON + Hall & Bathroom Fans ON, 50mV scale


                    Bathroom Fan ON at Motor Terminals, 100mV scale


                    Gene and Kim
                    2015 Grand Design Reflection 317RST
                    2017 RAM 3500 CC, LB, 4x2, 6.7L CTD

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                    • #11
                      Gene,

                      Nice! We are planning on looking at my rig a day next week. My buddy will bring a scope and a spectrum analyzer to see what's going on in my Imagine. The kitchen roof fan, hood range fan and bathroom fan all degrade the TV signal on my rig.

                      Jim
                      Last edited by Guest; 09-26-2019, 08:50 PM.

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                      • #12
                        Originally posted by MidwestCamper View Post
                        Gene,

                        Nice! We are planning on looking at my rig a day next week. My buddy will bring a scope and a spectrum analyzer to see what's going on in my Imagine. The kitchen roof fan, hood range fan and bathroom fan all degrade the TV signal on my rig.

                        Jim
                        A spectrum analyzer crossed my mind, alas my other meter with FFT is on the fritz.
                        Amazing what can be gotten now days since FFT and cheap PCs and tablets came along.
                        I was remembering analog microwave equipment requal when we used Tektronix 491 and 492 (~$20K).
                        Came across this youtube Tektronix 492 and 496 Portable Spectrum Analyzers. It put a smile on my face
                        Gene and Kim
                        2015 Grand Design Reflection 317RST
                        2017 RAM 3500 CC, LB, 4x2, 6.7L CTD

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                        • #13
                          I used a Tektronix Spectrum Analyzer when I was at Chrysler but its been so long I can no longer remember the model. Used AstroMed strip chart recorders back then too. Things have advanced but that old equipment was accurate then and now.

                          What do you do for a living Gene?
                          Last edited by Guest; 09-28-2019, 06:48 AM.

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                          • #14
                            Originally posted by MidwestCamper View Post
                            What do you do for a living Gene?.
                            I think "gbkims" and "Gene" are pseudonyms for "Gandolf". (Love Gene's posts--he's got to be part wizard with all that knowledge he has in his head!)

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                            • #15
                              Looks like he has the background for sure. The TV issue from the fans is a big problem. Curious if folks have the same issue with the king antennas?

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