@TabloEngineering @TabloSupport @Anyone… I have had in the same location and position my Tablo and 2 antennas, joined by a coupler. I went from 11 channels out of 14 with green dots, to 4 with a green dots out of 9. I know leaves are out on trees, but I am in line of sight of the transmission tower, and less than 4km away. 1 antenna is amplified while the other is not. I tried repositioning but I can’t seem to improve my situation. Any idea? Anyway to check the signal strength and quality on it’s own instead of the 3 colors dot representation? Any issue in using a combiner? It had worked fine over winter for me.
Thanks, any leads is appreciated.
It sounds like you may have some sort of failure in you antennas or cabling.
It is possible the tuner in the Tablo could be going deaf. However, it is easier to test the antenna system first.
Did the situation degrade suddenly or over a longish period of time?
Why two antennas? Are all the transmission towers within 4 km? That shouldn’t require more than one omni directional antenna. Even un-amplified rabbit ears in a basement should work at that distance unless all the transmitters are very low power. Of course, if the cable between the coupler and one of the antennas is half a wavelength different from the connection to the other antenna, the antennas could be cancelling each other out and reducing your signal strength.
Is your coupler a duplexer which only allows VHF from one input and UHF from the other, or is it just a full frequency bandwidth signal splitter?
Either way, disconnect one antenna. Search for channels. Do you still get 4 out of 9 showing green? If so, switch which antenna is connected and try again. That should tell you if one of the antennas has developed a problem. You can do the test with the splitter still attached but it might be better to use a barrel connector to rule out the splitter as the failed component. If it’s not a duplexer and you don’t have a barrel connector, swap which antenna is connected to which input to see if the channels which are primary on the other antenna get better or worse.
If the situation doesn’t change when testing individual antennas, you may want to try new coax between the Tablo and the coupler, and / or between the coupler and the antennas. You may find water in the coax, if it’s outside, or an animal has damaged the coax inside or outside.
@lambert: Thanks for the reply. The coupler is a simple cheap, full bandwidth (5Hz-1000Hz) splitter with 2 in/out and 1 out/in.
I use 2 antennas as my transmitters are about 135 degrees apart and I don’t want to put an omni on the roof, I am using 2 directional antennas in windows, pointing in 2 directions.
Since you got me thinking, I started by removing the splitter and pointed each antenna separately as a test. I don’t recall originally what channels each allowed me to see, so it’s not a perfect test. Nor can’t I get a TV in there easily to compare tuner sensitivity.
So, I took the un amplified antenna and get 3 channels in green. If I use just the amplified one pointing in the same direction, now the channel list jumps to 6. But placing the unamplified “leaf” antenna in a new location, I get 14 channels, with about 12 in green. Much better!
So in light of this, I played with different combination.
Now, the fun part started. I was getting different results all the time. Same antenna, same location. Quality dropped on good channels, new channels came up. Every test displayed something else.
I’m inclined to believe the tuners could indeed becoming desensitized at this point. I left things in a state where I have some channels, more than yesterday. I will see if tonight that changed without touching a thing.
I think the Tablo receiver is notorious for not being able to get the same readings twice. I’d to ten channel scans, painful, yes, and average the results. Bare eye line of site to the transmission towers. Sometimes the Tablo shows those channels yellow. But most of the time Tablo shows them full green. If the amplifier is separate from the antenna, you could try using it with the “leaf” antenna.
VHF/UHF propagation can change based on time of day, weather, … but that mostly affects edge/tropo propagation. Line of sight should not change much. Hopefully, at 4km, you won’t be using anything but line of sight.
Buildings in the way could cause reflections and whatnot. Aircraft could cause reflections that change your readings often. Even big trucks on a busy highway placed just right could cause rapid shifts in the quality of the signal. I don’t know how urban your environment is.
I’m at the same altitude as the broadcast towers and basically have valley between the towers and me. There are hills and a 50,000 person city in the middle but nothing tall enough to get in the way.