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I disconnected and bypassed the preamp, and removed the DC power inserter tap from the down-lead. I reinstalled an LTE filter between the antenna balun and the down-lead.

For the baseline test, I removed the POE filter and 3:1 splitter fixture from the plant. I used an F81 barrel connector to join the down-lead from the antenna to the longest drop. The second 2:1 splitter connecting the TiVo Bolt and the LG SJ8500 TV was removed, and the Ethernet-to-Coax MoCA adapter was removed. The drop lead was connected directly to the TiVo or LG for testing.

The TiVo is a TiVo Bolt DVR, with four digital tuners, running the New Experience3 UI. The signal strength and SNR values were viewed from a diagnostic screen (TiVo Central ->Settings&Messages ->Help ->Account&System Info ->Diagnostics). This signal strength is given in a whole number percentage (0% to 100%). SNR is reported as a whole number dB value. The TiVo has an automatic gain circuit which typically limits the signal strength to a value of "72%".

The LGTV is an SJ8500. The manual tuning under the "channels" page in the system settings menu provides real time "signal strength" and "signal quality". Both values are reported in whole numbers on a scale of 0 to 100.


For the non-preamp evaluation, the POE filter and splitter fixture was re-installed in the plant (the three way splitter provides in-band OTA and MoCA data to three drops). The evaluated drop was split prior to the TiVo or the Television, respectively.

The CM-2018 antenna is mounted on the roof, approximately 28' off the ground (~39' ASL). The orientation was verified by magnetic compass, at 166º magnetic.




Despite having the strongest reported signal from TvFool, the evaluated signal strength for Channel 31 is lower than six other stations with weaker reported signals. With the splitter installed, both 58.1 and 29.1 have macro-blocking issues. As noted previously, without the LTE filter channel 29 can't achieve a signal lock.
 

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Despite having the strongest reported signal from TvFool, the evaluated signal strength for Channel 31 is lower than six other stations with weaker reported signals. With the splitter installed, both 58.1 and 29.1 have macro-blocking issues. As noted previously, without the LTE filter channel 29 can't achieve a signal lock.

First, I don't know what "power base" means. I've never seen that term before. I assume it means Signal Strength.

Your TiVo Bolts seem to be just like my TiVo Roamio. Even though the Diagnostic says "Signal Strength," it is not. It's just Signal Quality (SNR) in %. You'll notice that the Signal Strength % and SNR dB exactly track each other. A true Signal Strength meter will not track SNR. There should be cases where the Signal Strength is up and the SNR is down and vice versa.

It's not clear to me exactly what LG Signal % is showing. Nearly 100% in every case doesn't make any sense. The only number that should always be 100% is Symbol Quality. I can't really use that until I understand what that is.

You probably should not use KEZT 23 since it is transmitting from N. Sacramento, not Walnut Grove. You're probably not pointed at it.

With the high insertion loss you're saying that 29 and 58 dropped to an SNR of 18 dB and you're getting drop outs. This should not be happening with an SNR of 18 dB. Signals should be solid down to 15.2 dB, especially on UHF where noise is almost non existent. I noticed that 6 and 10 went up a little on the LG with higher insertion loss. This probably a clue but I'm not sure what it is.

It seems your reception is fine with just an antenna feeding a TV. I can't help but wonder if your ethernet to RF converters are generating spurious signals down in the UHF band. Your results with the kind of signals you have don't make any sense. Interference can certainly cause SNRs to lower and cause instability at low SNRs. I've seen this kind of issue with KTVJ on RF 4 (low VHF) when there's intermittent noise. I've seen dropouts with low SNRs that would be solid on UHF. You really need a spectrum analyzer to verify this.

I have decades of troubleshooting experience with electronics of all sorts and every time a situation comes up that defies what I know has to be correct, it turns out there's some missing piece of information. I know you have strong enough signals to tolerate the high insertion loss in your system without adding a preamp. When the missing puzzle piece is found, everything falls into place and makes sense.

Looking at just the TiVo numbers and knowing what they mean, you have no idea how strong any of the stations are. KMAX could very well be the strongest signal. You really need to look at the input to your TV with a spectrum analyzer. Short of that, the only real solution is separate the two systems. You could have several problems at the same time; multipath from the tree, intermods from an overloaded preamp and converter interference.

From what you've posted it looks like one antenna feeding one TV works fine. If that's true, then the issues are within you system and not external.

Chuck
 

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"Power base" is just an abbreviation from my tracking spreadsheet, "power"= "signal strength" + "baseline" referencing the configuration. The same shorthand notation for "power" and "no Preamp" meaning "Signal Strength with the primary splitter installed, but no preamp"... my apologies for the lack of clarity.

I've also noticed that the TiVo "signal strength" number (that's how it's described on the menu page- it's the same number that appears under the "antenna signal strength" on the Channel Settings page, but this screen allows you to access it without suspending the other active tuners) tracks with SNR, although I don't have much confidence that the "signal strength" shows much of anything relevant, given the automatic gain control applied.

The LG software screen shows "Signal Power" and "Signal Quality", but there's nothing in their documentation to describe what the numbers are measuring. "Signal Quality", or as I abbreviated as "Signal Q", stays right around "100". The Signal power will fluctuate, but the Quality indicator, if it moves at all, only moves a couple numbers (ie, from "100" to "98")

I believe that KEZT is coming from the tower behind the Sacramento Bee, at 22nd & R St. It's less than two miles away, and you are correct that I'm not pointing at it. The reception is actually better quality than KUVS 18 (19.x), which is also not in the typical direction, but the translator/repeater is an easier catch.

I suspect that the dropouts I am seeing are multi-path related, and for whatever reason they appear more frequently with the higher insertion loss, but again that was the original reason for my post. They aren't consistent, but are more pronounced when the wind is blowing.

For what it's worth, in both of the test scenarios, the ECB bridges were powered off- and the ECB adapter at the TV was completely removed (it still is). I have an additional 2:1 splitter installed at the TV/TiVo end so that I could feed the same signal to both the TV and the TiVo at the same time.

Unlike yourself, I don't have a spectrum analyzer. I'm a retired newspaper printer, but like you I agree there's a piece of the puzzle that's missing. The problems may very well vanish this winter, when the leaves on the neighboring tree have dropped off.

Thanks for your expertise and your indulgence. I do appreciate the education.

-Regards,

Bruce
 

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Musical Chairs

Yes, H&I is moving to 58.2
https://www.handitv.com/wheretowatch/

Start TV (a new macho women channel) is displacing Decades TV on 13.2 Monday, Sep 3.

Movies! is a product of both FOX and Weigel Broadcasting and could be going to either channel 40 or 10.3.

Weigel Broadcasting has a hand in MeTV, Start, Decades, H&I, and Movies! and the CBS network plus other local stations so they could be interchanged anywhere.
https://www.abc57.com/news/weigel-broadcasting-co-to-launch-new-start-tv-network-in-association-with-cbs-television-stations
 

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After considering Chuck's helpful input, I've spent some time reworking my coax plant. To wit:

1.) The pre-amp and associated power injector have been completely removed, along with the LTE filter. The coax down-lead from the antenna balun now passes through a lightning surge suppressor, then into the attic where it makes a head end connection with a balanced three way splitter.

2.) I removed the MM-1000 external MoCA adapters. I am still using a MoCA network to provide internet services (it's needed for at least one location), but am relying upon the native MoCA client in each of the TiVo Bolt DVRs, and I replaced the MM-1000 that was at the router with a TiVo branded "Bridge"- a MoCA 2.0 ECB. The net data throughput is 400 Mbps, but while using the Extended D band (1150 MHz) there are no bonded channels in use.

3.) While I was up on the roof, I verified both the orientation and level of the Channel Master CM-2018 antenna. The antenna mount straddles a roof ridge that has a compass bearing parallel to the ridge of 125º, so I used that ridge as a directional aid to calibrate the antenna direction when mounted to the rotator box (in other words, I have a fair amount of confidence that the antenna is pointing within a couple of degrees to the desired compass direction indicated on the rotator control).

4.) The coax drop leads connect to the TiVo dvd's, and the drop to the utility room is diplexed, with the SAT port connecting to the TiVo bridge, and the UHF port connected to a Tablo DVR. Outside of the three way splitter and this diplexer, there are no other splitters installed in the plant. This is as about as clean as the plant can be.

From a pictogram, this arrangement is as follows:



5.) Using the TiVo on screen display, I recorded the reported values for Signal Strength (%), and SNR (dB), with the antenna positioned in prime directions for each of the three main compass bearings (164º, 166º, and 167º).

I had created a worksheet showing the calculated distribution loss and noise margin for each station. To that document, I added the results for the signal strength evaluation. The results are as follows:



In general, despite the calm wind conditions, I was still seeing some signal bounce on channels 29, 31, and 58. Despite aiming the antenna in the prime direction for those stations, the signal was still weaker on those stations than the other channels. By moving the antenna to a bearing of 174º, I was able to improve the signal strength, especially on Channel 31, although the signal strength still bounces. For evaluation purposes, I moved the antenna in one degree steps from 160º to 180º to search for the best combination of results. At the lowest power points in the bounce (typically where the reported strength dropped below 50), I would see pixellation and drop outs on the display.

Is it correct to assume that the signal bounce is a condition of multi-path, likely from the nearby tree? I've been assuming that is the case. The antenna bearing still passes through the tree at the "improved" direction, but my guess is that the LOS path is more direct. Both the signal strength and the SNR bounce occur at the same time, although not to the same relative variance. The signal strength does not exceed 72%, which I believe is a function of the TiVo AGC circuit. I don't have a spectrum analyzer.

Thanks again for all of the input. I suspect this will be as good as I can expect, until the leaves drop later this winter.

- Bruce
 

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In general, despite the calm wind conditions, I was still seeing some signal bounce on channels 29, 31, and 58. Despite aiming the antenna in the prime direction for those stations, the signal was still weaker on those stations than the other channels. By moving the antenna to a bearing of 174º, I was able to improve the signal strength, especially on Channel 31, although the signal strength still bounces. For evaluation purposes, I moved the antenna in one degree steps from 160º to 180º to search for the best combination of results. At the lowest power points in the bounce (typically where the reported strength dropped below 50), I would see pixellation and drop outs on the display.

Is it correct to assume that the signal bounce is a condition of multi-path, likely from the nearby tree? I've been assuming that is the case. The antenna bearing still passes through the tree at the "improved" direction, but my guess is that the LOS path is more direct. Both the signal strength and the SNR bounce occur at the same time, although not to the same relative variance. The signal strength does not exceed 72%, which I believe is a function of the TiVo AGC circuit. I don't have a spectrum analyzer.

Thanks again for all of the input. I suspect this will be as good as I can expect, until the leaves drop later this winter.

- Bruce

It sure looks like tree induced multipath. Here's a page that illustrates what's going on. Scroll down to the trees.

http://www.hdtvprimer.com/ANTENNAS/siting.html

Your antenna has a wide 3dB beamwidth, 30 degs or more. In a normal situation moving the antenna even a few degrees wouldn't make any difference. It's the multipath that's making the SNR change.

By this December the trees should be bare enough to see an improvement. Maybe you'll be lucky with KQCA and KSPX when they move to lower channels in May 2020.

I don't think the TiVo is limited to 72%/29 dB SNR but 29 dB is a pretty high SNR. Even a tiny bit of multipath will lower the SNR below 30 dB. I have only two stations that regularly reach 31 dB. Occasionally under exceptional conditions, I've seen two stations briefly touch 34 dB. I can't remember anyone reporting SNR's much higher than that. The DTV transmitters themselves have an SNR which is typically in the 30's although I have heard of newer transmitters reaching the 40's.

Chuck
 

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Have not been on this site for a long time.Problems with computer or ISP or lack of skills,dont know,but its working real good now.Plus unable to climb my tower for 2-3 yrs.and gradually losing use of 3 out of 4 antennas,lost interest.Luckily, my last antenna working, is 91XG. Its ability to pull in hi/low VHF stations sometimes,eases the pain of losing my big winegard antenna to a bad amp,i think.Amazingly it still pulls in stations from walnut grove (85mi)with 100ft cable,just not consistent.
 

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As of this morning, 10/1, H&I now appears on KQCA's virtual 58-2. For whatever reason, it's also still available on virtual 10-3.

Movies! is nowhere to be found, and the moviestvnetwork.com website lists availability in Sacramento as "Coming Soon".
 

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As of this morning, 10/1, H&I now appears on KQCA's virtual 58-2. For whatever reason, it's also still available on virtual 10-3.

Movies! is nowhere to be found, and the moviestvnetwork.com website lists availability in Sacramento as "Coming Soon".
Virtual 10-3 has gone dark sometime this afternoon, so the transition to KQCA DT-2 (58.2 virtual) is complete.

I'll be curious if Movies!TvNetwork makes a return...
 

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Can anyone tell me what KXTV has done to require a rescan?

https://www.abc10.com/article/news/wondering-about-the-rescan-here-are-the-faqs/103-607646656

There are trailers running on air and this page, published Wednesday, that says "Our team of engineers have been working with new technology to improve both the strength and quality of the ABC10 signal for those who may have had a tough time watching us with their antenna. We’ve finished the testing phase of these improvements and are ready for our viewers to enjoy our programs. But you have to rescan to get those benefits. No need to wait, rescan today!"
 

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I think they finally built that channel 36 DRT they held a permit for.

- Trip
 

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I think they finally built that channel 36 DRT they held a permit for.

- Trip

KXTV is on the air using VC 10 / RC 36. I got an SNR of about 20 dB and that's competing with co-channel KICU. My Sony doesn't like VC 10 pointing to two different RF channels. It will not display a picture but does put up the correct PSIP data. I can tune it using direct RF entry on the MyGoTV portable.

Chuck
 
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