Scanning green dots


#1

I relocated my antenna today. When I did a channel scan I received 5 Green dots on all the channels I need.

When viewing tv, periodically the picture will become pixelated as if it is loosing signal. I plan on moving it to a higher point tomorrow.

I was confused as to why it would show such a good signal strength, but not perform as such.


#2

Signal strength and signal quality are two different measures. Signal strength shows the physical strength of the RF wave. Signal quality shows the level of errors and interference. The two measures are not the same. It is possible to have a strong RF signal with poor signal quality (i.e. error filled).

Tablo shows a static, one minute appraisal; it is not an ongoing monitor. Signal strength could be up at 9:15 and down by 10:30. Five green dots does not signify an ongoing strong signal nor necessarily a quality signal.

There are better, more dynamic signal monitors that show more aspects of a signal (like the ones above and others). At best Tablo’s signal meter is an advisory one - not a definitive one.


#3

I have a channel that shows 1 red dot on the Tablo scan yet comes in steady. So the dots are not the whole truth.


#4

I’m just the opposite. All Green dots, but pixelated from time to time. What are some common interference issues?


#5

Each tuner manufacturer has their own algorithm for measuring signal strength or signal quality. That’s another problem. The Tablo may say X number of dots while another tuner in the same house may say Y% signal strength.


#6

An airplane flying over the house.
A signal bouncing off a truck on a nearby road.
Multipath - when the same signal arrives out of sync using different paths.
Leaves swaying on a tree.
Heat and humidity.
Inclement weather near the transmitting tower.
If antenna in an attic, reflections off pipes and aluminum tape ducting.
Adjacent channel overlap.
With VHF signals, FM radio frequencies may interfere.
LTE (cell phone towers).
In home fluorescent lighting.
Microwave oven.
Noisy electrical motor somewhere in the house.

Signal strength varies during the day - sun’s position may affect it.


#7

I told my Tablo to report the whole truth and nothing but the truth and it replied, “You think you’re Perry Mason? Watch some MeTV.”


#8

On this topic, has anybody ever seen a channel reported as 2 dots or 4 dots? In all of the testing I did with my unit, incrementally adjusting signal strength by inserting and removing attenuators of various values, every channel was always reported as 1, 3, or 5 dots. Never, ever anything else. Why? Aside from the incomplete picture of signal quality already mentioned, this suggests that even the signal strength as reported by Tablo is just assigned to one of three “levels”, and I’m sure less-than-ideal-strength signals are frequently just rounded up into the 5 dot category.


#9

Same here - 1, 3 or 5. Never seen a 2 or 4.


#10

Maybe they couldn’t agree on a color scheme for a 4th and 5th level :man_shrugging:


#11

Okay, I see the point about signal strength and signal quality. This mist have something to do with me changing my mind every other day on keeping the tablo vs going back to paid locals


#12

What kind of antenna do you have? How far are you from the broadcast towers? Do you live in an apartment or house? A lot of this is resolvable. I had pixelation on one channel and I worked through the problem.

Give us a TVFool report. If you have an attic then a good antenna at 30 to 40 miles with a good preamp will work very well. Too many antennas are all hype and PR.