I have a Tablo Dual that I have been using successfully for a year and a half. My antenna is outdoor and mounted on my roof and the Tablo is hard wired to my router. I recently got into amateur radio as a hobby and I have noticed the live tv will pixelate and freeze both on the Roku app and the web app when I am transmitting with 1 Watt of power or more on the 2 Meter Band (144-148mHz). When I transmit above 75 Watts or more power on my HF radio and the Tablo receiver is active for live tv or recordings, I have noticed the Tablo will stop and lights will flash as though it is resetting. I am wondering if the receiver is being overloaded by my signal and if there is anything I can change to prevent this. I have already attached ferrite beads to the power, coax, and ethernet on the Tablo in the hope of reducing stray RF. The pixelation and freezing still occurs if I use a radio outside house and away from the room the receiver is set up.
The lowest Over the Air TV channel in my area is broadcast around 180mHz. Does anyone have any experience with this? Has anyone identified a filter or set of filters I could put in line with the coax from my antenna to the Tablo that would attenuate these lower frequency signals? I am currently in an either or situation. Either I can enjoy my new hobby or I can stay off the air and keep my wife happy by letting her shows record. Any help or suggestions would be welcome.
Welcome to the Tablo and Amateur Radio community. There are a lot of Hams here and I’m sure many will be willing to assist, with suggestions at least.
The more info we have the better the suggestions will be, like types of antenna, polarization, feed lines, etc.
You might need to start with quad shield coax at all locations in the house. You could also try the Tablo on a wireless signal to eliminate any signal feed on the Ethernet cable. Might need a low pass filter on the HF rig and a high pass filter in the TV antenna circuit.
How does your TV respond to your radio transmissions while on direct connect to your outside antenna?
Haa, I’ve not transmitted on HF since I got the Tablo. Running a Kenwood TS-480HX and I use to hit 200 watts from time to time. My suggestion is to put a really good high pass filter on the input to keep the RF from the HF rig from hitting the receivers. Also you may get some feedback on the ground side of things if you don’t have a proper choke on the antenna feed. i.e. RF going back down the coax braid. I use to turn off computer monitors and such when I would key up until I added a choke on the feed. Just be sure to do that right.
Edit: High pass on the input of the Tablo and a proper chock on the antenna feed of the HF antenna.
I am currently running an Icom IC-7100 as my main radio. For 2 meters and 440, I am using a multiband quarter wave vertical about 3 meters from my over the air antenna. For 20 meters, 40 meters, and occasionally 17meters, I am using a home made fan dipole with a 1:1 air core hand wound balun as described in KG0ZZ’s video’s on youtube.
The fan dipole is set up in an inverted V with the primary directions of radiation to the east and west. Should I have some other type of choke on my antenna feed line? If so, where should it be located? Near the radio?
I am currently using this antenna for over the air TV, which I believe is horizontally polarized: https://www.amazon.com/dp/B07PFFYX5L?ref=ppx_pop_mob_ap_share
I do not currently have a TV hardwired into the feed from my over the air antenna, so I cannot speak to how the signal acts on anything besides the Tablo. What would you recommend for a high pass filter on the coax going to the Tablo? In addition to the signal breaking up using my base station, transmitting on a Baofeng UV-5R on low power in my front yard causes the signal on my Tablo receiver to pixelate and freeze.
Rolesville, depending upon your QTH, you might receive enough TV stations with an indoor antenna, which might not pick up as much RF as your outdoor antenna. Can’t hurt to try as an experiment. You can make a quick indoor antenna using some RG-59 or equivalent coax and strip off the the Shield a few feet, using the inner conductor as the antenna.
Eventually you should try with the TV antenna connected directly to the TV and see if you still get interference. If you do then you would have to solve that issue before you could have confidence the TABLO could work properly in strong RF fields.
One other thing; you can put the TABLO app on your cell phone and stream the TV show and watch the screen of the cell phone while you transmit to see if any RF remediation efforts are successful. You would need WiFi enabled on your home router of course.
Wolfpack, thank you for your recommendations. I’ve used the app previously while I am outside on the ladder tuning my over the air antenna. I have an older home with a metal roof, so signals on an indoor antenna are too poor to be usable on the tv.
I’ll hook up my antenna feed to a tv to see how it acts, but I bought the Tablo to have the dvr and I do not want to give up on the system. I’d rather find a way to keep the tablo from being overloaded during transmissions. Where could I find a high pass filter to add to my antenna feed and what should I be looking for to attenuate signals below 180MHz?
More info and testing needed. You should make a recording on the Tablo while transmitting and later play back the recording without transmitting. This would be to see if the interference to the TV reception initiated downstream from the Tablo Ethernet connection. What kind of media player are you using? There exists the possibility the RF is affecting the media player and not the Tablo. It’s a stretch but worth investigating.
You could also try an attenuator in your OTA circuit to the Tablo, if all preferred stations shown five green dots at present. You could try cutting down the OTA signal until the green dots change, and then back off a bit. This might help reduce overload from your radio transmissions.
Keep in mind a balun is not a choke. A balun is an matching device where the choke is used to block or filter RF from coming back down the coax. The terms get really confusing as a choke can often help to match as well. To confuse issues even more check out an air choke or “Ugly Balun”. I’ve had great luck with the air core for HF. You want it near the antenna.