Very poor to 'none' signal quality

Reception, channel detection, network issues, CableCARD setup, etc.
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leone007
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Very poor to 'none' signal quality

Post by leone007 » Fri Jun 28, 2019 8:05 am

I bough my HDHomeRun EXPAND 4 months ago, I installed it behind a two way splitter, and most of the channels were fine, only a few with poor signal quality. I never had the time to deal with this, since the most important channels were fine. 2 weeks ago my most important channel started producing bad quality signal, and the signal quality dipped below 60% (I only checked it in tvheadend) Behind this splitter there is a 3 way splitter, connected to 3 different TVs where ALL the channels were OK.

I asked my provider to send engineers to fix the problem, didn't know if it was cable related or provider related. They changed all the splitters to brand new ones, that has no signal loss (according to the engineers). They even checked the signal quality on the end of my cable that is connected to the HDHomerun EXPAND, and it was perfect, so they didn't change a thing apart from the splitters.

Now in the original location (behind the 2 way splitter) I get this:

Image

If I connect the HDHomerun to the cable that goes to the living room TV (this is behind a 2way and a 3 way splitter as any other TV in my household, and shows in its menu 97% signal strenght, and 100% signal quality, and every single channel plays perfectly well) I get this on the HDHomerun:

Image


Is my device faulty?
Is it possible that the AC adapter picks up some kind of RF noise?
I'M running out of ideas here. :(

signcarver
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Re: Very poor to 'none' signal quality

Post by signcarver » Fri Jun 28, 2019 9:06 am

When at 100% strength, you don't know how much above 100% it is and it can easily be too much power. So whenever someone posts 100% strength, I suggest attenuating the signal down until you get a "real" number slightly below 100% prior to running any other troubleshooting.

In some cases, regardless of strength, the issue is rf interference at that particular location and one can try moving it around to see if quality improves as well as double check connections on all devices.

NedS
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Re: Very poor to 'none' signal quality

Post by NedS » Fri Jun 28, 2019 9:46 am

Can you tell me the Device ID printed on the bottom of your HDHomeRun unit?

leone007
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Re: Very poor to 'none' signal quality

Post by leone007 » Fri Jun 28, 2019 10:31 am

NedS wrote:
Fri Jun 28, 2019 9:46 am
Can you tell me the Device ID printed on the bottom of your HDHomeRun unit?
142039C5

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jasonl
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Re: Very poor to 'none' signal quality

Post by jasonl » Sat Jun 29, 2019 3:54 pm

Yes, your signals are too strong. Everything is registering about 130% strength. Recommend removing the amplified/powered splitter and going back to a regular passive splitter.

leone007
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Re: Very poor to 'none' signal quality

Post by leone007 » Sun Jun 30, 2019 6:50 am

jasonl wrote:
Sat Jun 29, 2019 3:54 pm
Yes, your signals are too strong. Everything is registering about 130% strength.
How do you know this?

signcarver
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Re: Very poor to 'none' signal quality

Post by signcarver » Sun Jun 30, 2019 8:06 am

From your deviceID, that is why it was asked for as SD can see more diagnostic data.

Like I said earlier, first step in troubleshooting is always getting strength down to as close to 100% as you can, the problem is until you are below 100% you won't know how much above it really is.

Also given the frequency it is on, it wouldn't surprise me if in some expand markets that the issue might be lte (cellphone) interference but that is harder for them to see if there is already an issue of everything being too strong.

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jasonl
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Re: Very poor to 'none' signal quality

Post by jasonl » Mon Jul 01, 2019 12:11 pm

The scan logs we see include the raw signal strength (not capped at 100%)

gtb
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Re: Very poor to 'none' signal quality

Post by gtb » Mon Jul 01, 2019 12:37 pm

jasonl wrote:
Mon Jul 01, 2019 12:11 pm
The scan logs we see include the raw signal strength (not capped at 100%)
And why I understand that most of your customers do not really understand RF physics, for those of us who have that degree, we do wish we had a bit more visibility into some of the raw data.

ebo
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Re: Very poor to 'none' signal quality

Post by ebo » Mon Jul 01, 2019 5:47 pm

I agree that I'd like to see actual signal strength levels in HDHomeRun Config GUI but a modification that everyone should understand is to allow the bar graph and percentage to exceed 100%, up to whatever level is sure to kill reception. When the bar graph exceeds 100% (or whatever level is known to be OK) it could switch from green to red. There could also be a note that says if the bar is red, reduce the input level. That would reduce the number of posts that say, "My tuner doesn't work and I know the level is good because it's 100%."

Billi23
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Re: Very poor to 'none' signal quality

Post by Billi23 » Mon Jul 01, 2019 8:53 pm

ebo wrote:
Mon Jul 01, 2019 5:47 pm
I agree that I'd like to see actual signal strength levels in HDHomeRun Config GUI but a modification that everyone should understand is to allow the bar graph and percentage to exceed 100%, up to whatever level is sure to kill reception. When the bar graph exceeds 100% (or whatever level is known to be OK) it could switch from green to red. There could also be a note that says if the bar is red, reduce the input level. That would reduce the number of posts that say, "My tuner doesn't work and I know the level is good because it's 100%."
+1
Or at least post a chart of what Signal Strength % = what dBmV since we can view the dBmV level.
Signal Strength 95% = -3.5 to -3.0 dBmV ?

I assume that 100% = 0.0 dBmV ?

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jasonl
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Re: Very poor to 'none' signal quality

Post by jasonl » Tue Jul 02, 2019 12:06 pm

100% = 0dBmV, and a change of 5% is a 3dBmV difference.

Billi23
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Re: Very poor to 'none' signal quality

Post by Billi23 » Tue Jul 02, 2019 12:36 pm

Thanks

Code: Select all

SS%  dBmV
0%   -60 dBmV
5%   -57 dBmV
10%  -54 dBmV
15%  -51 dBmV
20%  -48 dBmV
25%  -45 dBmV
30%  -42 dBmV
35%  -39 dBmV
40%  -36 dBmV
45%  -33 dBmV
50%  -30 dBmV
55%  -27 dBmV
60%  -24 dBmV
65%  -21 dBmV
70%  -18 dBmV
75%  -15 dBmV
80%  -12 dBmV
85%   -9 dBmV
90%   -6 dBmV
95%   -3 dBmV
100%   0 dBmV
105%   3 dBmV
110%   6 dBmV
115%   9 dBmV
120%  12 dBmV
125%  15 dBmV
130%  18 dBmV
And I think the specs for US Cable are 0 dBmV +/- 15 dBmV?
Not sure about OTA ATSC.

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jasonl
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Re: Very poor to 'none' signal quality

Post by jasonl » Tue Jul 02, 2019 1:44 pm

US cable is -12 to +12. OTA is a min of -30 to have a reasonable chance. If the signal is really clean it might come in a bit lower. Max for OTA isn't something that can easily be expressed, because overload is a cumulative result of everything going in, including non-TV signals like FM radio and LTE. Non-TV signals often end up being a bigger problem than TV, since most people live a lot closer to a cell phone tower than they do a broadcast station, and most antennas are still designed to have peak gain at the frequencies that are now used for LTE.

leone007
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Re: Very poor to 'none' signal quality

Post by leone007 » Fri Jul 12, 2019 7:03 am

Hey guys, thanks for the help and sorry for the late reply, I was on a holiday in Italy. I bought a 0-20 db attenuator, installed it, and now everything is on 100%. I'm ever so grateful for your help.

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