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post #16471 of 18789 Old 04-12-2018, 07:43 AM
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Quote:
Originally Posted by minakami View Post
tun: ch=8vsb:43 lock=8vsb:647000000 ss=77 snq=67 seq=100 dbg=-5600/19389
Isn't 67 a rather low signal quality for a signal strength of 77? What's the dB equivalent? I think that's what the KCSM complaints are, good signal but low signal quality.

I just looked at KCSM and KTVU again. KCSM is 2 dB weaker than KTVU. KTVU signal quality is 23 dB and KCSM signal quality is 18 dB. Now that I think about it, I can't remember ever seeing KCSM with a signal quality higher than 18 dB no matter how good conditions get. OTOH KTVU rises to as high as 25 dB at times.

I wonder what the highest signal quality anyone gets on KCSM?

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post #16472 of 18789 Old 04-12-2018, 09:07 AM
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This is probably a Trip question. I attached an image showing the service contours for RF 28 after the repack. Even though I see some overlap with KBCW by KKPM and KMMD, those are part of the repack. Does this mean KMMW-LD will be allowed to stay on 28 even with interference to KBCW? KMMW-LD has not filed anything at all with the FCC in the last year.

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post #16473 of 18789 Old 04-12-2018, 10:13 AM
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It appears that by a strict definition of displacement, KMMW-LD is displaced. It causes something like 1.6% interference to KBCW.

The window is open until May 15, so we'll see if they file anything. If not, they may try to change antenna pattern or otherwise tweak things on the current channel when those types of applications are permitted again. Or they may wait and see if KBCW complains at all; if they don't, then I don't think there's anything forcing KMMW-LD to move.

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post #16474 of 18789 Old 04-12-2018, 10:45 AM
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Quote:
Originally Posted by Calaveras View Post
Isn't 67 a rather low signal quality for a signal strength of 77? What's the dB equivalent? I think that's what the KCSM complaints are, good signal but low signal quality.

I just looked at KCSM and KTVU again. KCSM is 2 dB weaker than KTVU. KTVU signal quality is 23 dB and KCSM signal quality is 18 dB. Now that I think about it, I can't remember ever seeing KCSM with a signal quality higher than 18 dB no matter how good conditions get. OTOH KTVU rises to as high as 25 dB at times.

I wonder what the highest signal quality anyone gets on KCSM?

Chuck
I guess you are not a fan of Toast0's charts, my findings last night and KCSM them selves reporting that they have transmitter problems starting on April 3, 2018.

I went back as far as November 1, 2017 and saw on Toast0's charts a poor looking chart for KCSM.

Compare Toast0's chart for RF 43 with charts of other stations on Sutro like RF44, and RF 45. And other stations like RF19, RF 29, RF 30, RF38 and the list goes on.

RF 35 shows when the tuner was not available as does RF 48 plus additional problems. You need to go to RF 20 for a chart that is worse.

Highest Signal Quality for KCSM in the past for me, likely near 90-100%.

SHF

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post #16475 of 18789 Old 04-12-2018, 12:34 PM
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Quote:
Originally Posted by SFischer1 View Post
I guess you are not a fan of Toast0's charts, my findings last night and KCSM them selves reporting that they have transmitter problems starting on April 3, 2018.

I went back as far as November 1, 2017 and saw on Toast0's charts a poor looking chart for KCSM.

Compare Toast0's chart for RF 43 with charts of other stations on Sutro like RF44, and RF 45. And other stations like RF19, RF 29, RF 30, RF38 and the list goes on.

RF 35 shows when the tuner was not available as does RF 48 plus additional problems. You need to go to RF 20 for a chart that is worse.

Highest Signal Quality for KCSB in the past for me, likely near 90-100%.

SHF

It's not as helpful as you might think. Firstly, it's just what one person receives at one location. It may or may not be applicable to what's going on with the station. How many times have we seen one person having a problem when no else is? Second, the graph is in percent. What does signal quality in % equate to in dB? I have no idea what's good and what's bad. The month of April shows the signal quality as 25% for KCSM. I guess that must be fine as KCSM is nominal here. Signal Strength in % doesn't mean anything unless you happen to know that 100% equals 0 dBmV and that each 5% drop equals a 3 dB drop as reported by toast0 in his 1-8-2013 post.

The graph for April looks like Symbol Quality is mostly 0%. That would mean the signal cannot be decoded. Clearly that's not true because I'm decoding it here. Based on that I don't trust any of the numbers for KCSM.

I'd like to see reports of Signal Quality in dB from as many different people as possible.

Chuck
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post #16476 of 18789 Old 04-12-2018, 02:08 PM
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Quote:
Originally Posted by Calaveras View Post
I'd like to see reports of Signal Quality in dB from as many different people as possible.

Chuck
I've got six antennas where I can take measurements of Signal Quality using my HD Home Run receivers, but quality is in percentage, not dB.
- CM4228/C5 combo pointed at 245 degrees (set for best overall reception of all stations) KCSM's signal has a Signal Quality of 75-78%
- CM4228 pointed at 220 degrees, KCSM SQ = 85%
- LP345 all band pointed at 345 degrees for RF channels 3, 4, 23 and 47, KCSM's SQ is 87%
- SR-15 UHF pointed at 210 degrees for best reception of South Bay stations, SQ is 77-80%
- XG-91 UHF on rotor has best SQ reception at 293 degrees and it's 58-73%, varying a lot with occasional picture pixelation.
- 8200U all band antenna on rotor has best SQ at 190 degrees and it's 73%. In other positions of the 8200, KCSM's quality is bouncing all over the place.

Sutro is at 268 degrees. Signal Strength and Symbol Quality for KCSM are both at 100% on all antennas. SQ of 55% is needed to produce a picture.

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post #16477 of 18789 Old 04-12-2018, 02:23 PM
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Thanks Larry! If 55% is the minimum Signal Quality to produce a picture then clearly 25% shown on toast0's graph is not useable. He's got some kind of reception problem that's unrelated to whatever trouble KCSM is having. 87% sounds like a pretty good number. Your wide ranging results on different antennas shows how sensitive reception can be to slightly different antenna locations and patterns.

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post #16478 of 18789 Old 04-12-2018, 02:36 PM
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I have a 91XG and HDHR4-2US pointed at Sutro from South San Jose and get 65% sq on KCSM while the other Sutro stations are 98%.

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post #16479 of 18789 Old 04-12-2018, 02:39 PM
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Quote:
Originally Posted by Calaveras View Post
It's not as helpful as you might think. Firstly, it's just what one person receives at one location. It may or may not be applicable to what's going on with the station.
...

The graph for April looks like Symbol Quality is mostly 0%. That would mean the signal cannot be decoded. Clearly that's not true because I'm decoding it here. Based on that I don't trust any of the numbers for KCSM.

I'd like to see reports of Signal Quality in dB from as many different people as possible.

Chuck
Very true, and I recently had an exchange with one of the station chief engineers about that same topic. There are a great many things that can affect one region in the bay area so they appreciate getting data from multiple areas of the service area. They do observe toast0's charts as one data point. I host another monitoring system, though it focuses more on analyzing the health of the demodulated MPTS. I've been working to fold in charts similar to toast0's since it appears he may be heading north. If you want to have a look at KCSM from midnight in Mountain View:

https://sfbayatsc.koherence.com/atsc...r&e=1523602799

(I'll just warn you that this site is not quite ready for regular consumption yet. The "e=..." limits the time range to today.)

The high 60's for "signal quality" is in the range of what I get for some channels. I don't know how SiliconDust computes signal quality so its difficult to say what it should mean to a demodulator (i.e. SNR, etc.) Usually for ATSC a low but steady SNR is preferable to a higher but oscillating SNR since the demodulators have a rough time following the changes. You can see that in the chart about noon. Signal quality appears to improve but the demodulator starts choking on the signal. This smells like some sort of environmental/atmospheric interference. I get similar effects for KKPX certain times of the year. This is for my particular setup in Mountain View. Further south in the bay different factors may be affecting reception.
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post #16480 of 18789 Old 04-12-2018, 05:49 PM
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Quote:
Originally Posted by minakami View Post
The high 60's for "signal quality" is in the range of what I get for some channels. I don't know how SiliconDust computes signal quality so its difficult to say what it should mean to a demodulator (i.e. SNR, etc.)

From the information I got from Larry it appears that 55% is 15 dB and 100% is 30 dB. That would make 3% = 1 dB. At least that makes some sense.

Chuck
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post #16481 of 18789 Old 04-12-2018, 05:55 PM
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Chuck, you have your face into a scope that you look at very occasionally. Yes it is good for some problems, but not KCSM's current ones.

Toast0's chart sample points are taken ~ twice a hour, 24 hours a day, 7 days a week, 365/6 days per year. Except when the tuner is needed to capture HDTV like I do. You will see a straight line when that happens. I have gone back to November 1, 2017 and KCSM had problems back then.

I have found that their is a direct correlation with the samples I take of the continuous transmitter stream to feed into TSReader. and what his charts show.

I have my Sony HDTV tuner displaying KCSM VC 60 RF 43 and the picture is breaking up very often. Not a fixed repeat rate but way too often. Often disappearing completely.

Have you looked at Toast0's charts for other Sutro stations like I suggested, they look very clean compared with KCSM and normal for most all stations.

On the chart for RF 43 click on the colored bars just to the left of the names on the right.

You will see that transport_errors jump all over as well as missed_packets.

Signal_to_noise improved ~ 12:12 PM. Mouse over the dots that show up when you click on a colored bar just to the left of the names on the right.

--------------------------------------------------------------

The full stream capture I took last night TSReader just could not process! Very unusual.

Toast0 data is collected by a HDHR Tuner, the earlier version with two antenna connections. Mine can now decode KCSM, last night it could not, but it stopped as soon as I looked at the HDHomeRun Config display again.

Moving on to my second HDHR, a newer one with one antenna terminal I currently have:

Signal Strength 80-91%, The Signal Quality 49-78% and the Symbol Quality is at 100% if the Signal Quality is 50% or higher.

The chart is jumping around just like my Sony HDTV. I can display the video along side the HDHomeRun Config display and I see the same Video problems as my Sony TV , if the Symbol Quality goes to zero (0) Signal Quality <=49% (RED) the picture freezes or breaks up.

---------------------------------------------------------

As I said, KCSM posted on:

https://twitter.com/KCSMTechIssues

KCSM Engineering

@kcs MTechIssues
Apr 3

KCSM-TV over-the-air is currently experiencing transmitter difficulties. We are in the process of addressing the issue. Thank you.

----------------------------------------------------------

What more can I say?

SHF
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post #16482 of 18789 Old 04-12-2018, 06:00 PM
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Quote:
Originally Posted by Calaveras View Post
Thanks Larry! If 55% is the minimum Signal Quality to produce a picture then clearly 25% shown on toast0's graph is not useable. He's got some kind of reception problem that's unrelated to whatever trouble KCSM is having. 87% sounds like a pretty good number. Your wide ranging results on different antennas shows how sensitive reception can be to slightly different antenna locations and patterns.

Chuck
No, it is 50%. 49% and Signal Quality changes to RED and Symbol Quality goes to zero (0%).

I see the same problems as Toast0's charts and I have sent a message to KCSM.

The KRCB purchase of KCSM link has gone bad, I am going to try and recover it from the Wayback Machine.

SHF
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post #16483 of 18789 Old 04-12-2018, 08:36 PM
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KCSM is RF 43, not close enough to LTE band to cause problems. I think they've got a bad transmitter.
No problem in Redwood City.
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post #16484 of 18789 Old 04-12-2018, 09:13 PM
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Originally Posted by dod1450 View Post
No problem in Redwood City.
Ok, everyone who does not not have a problem with KCSM tweet then so that they do not waste money on fixing something that does not need fixing.

The rest of us who do have a problem, switch to KQED. Oh wait, we all have already.

When they do fix it, look for a tweet from them. They have in the past after acknowledging a problem tweeted when they fix it.

And they have sent a lot of tweets lately, the April 3 OTA problem is still open.

"dod1450", what are you basing your no problem on?

SHF
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post #16485 of 18789 Old 04-12-2018, 09:32 PM
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Originally Posted by dod1450 View Post
No problem in Redwood City.
Not useful, sorry. I can watch KCSM just fine, although others can't. KCSM signal quality is degraded, but my SiliconDust tuner can still decode it.

To be useful you need to post signal strength, signal quality, and what tuner you're using as well.

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post #16486 of 18789 Old 04-12-2018, 09:35 PM
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The link for "“Who Will Pay For KCSM In The End?” is now good and a very interesting read.


https://www.avsforum.com/forum/45-loc...l#post56021428


SHF
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post #16487 of 18789 Old 04-12-2018, 09:47 PM
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KTLN wants another 90 days.

KTLN intended to commence channel sharing on April 20, 2018, however, at least one MVPD has advised the Licensee that it does not receive a
good quality signal at certain of its head ends. Fiber must be installed.

That likely means KAXT will file also shortly and no WKRP on Me.TV for much longer than planned.

SHF
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post #16488 of 18789 Old 04-13-2018, 07:28 AM
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Quote:
Originally Posted by SFischer1 View Post
The full stream capture I took last night TSReader just could not process! Very unusual.

Toast0 data is collected by a HDHR Tuner, the earlier version with two antenna connections. Mine can now decode KCSM, last night it could not, but it stopped as soon as I looked at the HDHomeRun Config display again.

Moving on to my second HDHR, a newer one with one antenna terminal I currently have:

Signal Strength 80-91%, The Signal Quality 49-78% and the Symbol Quality is at 100% if the Signal Quality is 50% or higher.

The chart is jumping around just like my Sony HDTV. I can display the video along side the HDHomeRun Config display and I see the same Video problems as my Sony TV , if the Symbol Quality goes to zero (0) Signal Quality <=49% (RED) the picture freezes or breaks up.

I'm not saying KCSM has never had a problem. All I can say is that whenever I've looked at KCSM I have not seen an issue. I don't look at it very often though and it's possible I've just been lucky. BTW, I look primarily at the TV and second at the spectrum analyzer to see the signal compared to other Sutro stations. I do not say that KCSM is okay just looking at the analyzer.

I see on toast0's graph that KCSM looks mostly okay since April 13.

This morning conditions are good with KTVU SNR 24 dB and KCSM SNR 20 dB. I see no issues with KCSM at 7 am.

BTW, you're saying that a Signal Quality on the HDHR of 50% will produce an error free picture?

Chuck

Last edited by Calaveras; 04-13-2018 at 07:37 AM.
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post #16489 of 18789 Old 04-13-2018, 08:29 AM
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Chuck,

I own a pile of HDHRs, and my observations of the HDHR3 are as follows:

On signal strength, 50 = -35 dBmV, and 100 = 0 dBmV. Converted to dBm, 50 = -83.75 dBm, 100 = -48.75 dBm.
On signal quality, 50 = 16 dB MER, 100 = 32 dB MER. (On rare instances, I can manage clean decodes at 48, which would be something like 15.4 dB, close to the theoretical minimum of 15.19 dB, but it's very fragile.)
On symbol quality, it's basically either perfect at 100 or 0 with errors.

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post #16490 of 18789 Old 04-13-2018, 09:16 AM
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Quote:
Originally Posted by Trip in VA View Post
Chuck,

I own a pile of HDHRs, and my observations of the HDHR3 are as follows:

On signal strength, 50 = -35 dBmV, and 100 = 0 dBmV. Converted to dBm, 50 = -83.75 dBm, 100 = -48.75 dBm.
On signal quality, 50 = 16 dB MER, 100 = 32 dB MER. (On rare instances, I can manage clean decodes at 48, which would be something like 15.4 dB, close to the theoretical minimum of 15.19 dB, but it's very fragile.)
On symbol quality, it's basically either perfect at 100 or 0 with errors.

- Trip
Good info, thanks. I knew about the dBmV conversion, but SiliconDust claimed signal quality percentage didn't have much meaning to anybody but themselves, and varied with the hardware. Although there may be some truth to that (pretty sure their tuners aren't calibrated spectrum analyzers) I may as well immortalize this in a spreadsheet (attached) so we can share results using standard units within the limits of SD hardware "calibration".

By the way, it looks like 65% signal quality is about 20.8dB using the above, so my results for KCSM in south San Jose agree with @Calaveras . Must be a heck of an antenna/balun/preamp setup to get the same SNR at more than twice the distance. Although I think that is further evidence their transmitter is distorting.
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I can only speak for the HDHR3, but the numbers lined up pretty closely to my Sencore analyzer. I've never tested to see if the HDHR4 or HDHR5 match those values.

- Trip

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post #16492 of 18789 Old 04-13-2018, 09:32 AM
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Quote:
Originally Posted by Trip in VA View Post
I can only speak for the HDHR3, but the numbers lined up pretty closely to my Sencore analyzer. I've never tested to see if the HDHR4 or HDHR5 match those values.

- Trip
HDHR4-2US drops out below 50% signal quality so must not be too different.

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post #16493 of 18789 Old 04-13-2018, 01:52 PM
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Interesting information on the HDHR percentages: Strength dBmV and dBm and Quality dB MER.

I have two older HDHR's (two inputs, two outputs - don't know the model number) and one HDHR4-2US (one input, two outputs). With the same signal going into the receivers (outputs from the same DA) I notice a difference in the receiver performance and the output levels shown for the different models. The two older models perform very much alike while the new one is sometimes quite different.

(To make sure it was the receivers and not the cables, I've switched the coax cables and receiver performance was the same.)

The Signal Strength and Signal Quality indications vary quite a bit between the two models. Here are a few examples. The first figure is the RF channel number then the SS and SQ for the older model followed by the SS and SQ for the newer HDHR4 then the dB SNR from my Sony TV.

RF CH Old New TV
------- -------- -------- ------
2 80/52 92/51 17.7-19.2
4 100/100 100/78 31.0-32.10 (Edit: sorry, the spacing between the columns isn't maintained on the saved copy.)
7 100/92 100/98 31.5-32.2
12 100/100 100/98 31.5-32.2
23 87/64 81/43 25.5-26.5
36 88/67 86/64 25.6-25.8
42 65/56 68/43 14.5 - no pic
47 85/54 84/51 23.8-24.4


You'll notice that the Signal Strength readings can differ for the same signal, sometimes higher, sometimes lower, and the Signal Quality is sometimes about the same while sometimes it's very different. There doesn't seem to be any rhythm nor reason for the variances.

One thing that's very noticeable is that if the new model receives any weak 8vsb signal the SQ is 43 no matter what the weak signal strength is. It can be 43 and I still get a picture as shown for channel 23. The old model shows any quality between 0 and 100, but usually has to reach 55% for the TV to produce a picture. (Some of you have indicated that you get a picture with the SQ as low as 48.)

I don't know if this comparison is of interest to anyone, but I thought some of you might like to see how the different receivers show different results. Have fun with it!

Larry

My complete SF Bay Area DTV Station Lists: http://www.larrykenney.com/sfonair.html
Lots of Broadcasting links and information: http://www.larrykenney.com/broadcast.html
Live reception scans from my HD Home Run receivers: http://www.larrykenney.com/hdhr/
Photos and info on my antennas: http://www.larrykenney.com/tvantennas.html

Last edited by Larry Kenney; 04-13-2018 at 01:55 PM.
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post #16494 of 18789 Old 04-13-2018, 08:38 PM
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Quote:
Originally Posted by Calaveras View Post
I'm not saying KCSM has never had a problem. All I can say is that whenever I've looked at KCSM I have not seen an issue. I don't look at it very often though and it's possible I've just been lucky. BTW, I look primarily at the TV and second at the spectrum analyzer to see the signal compared to other Sutro stations. I do not say that KCSM is okay just looking at the analyzer.

I see on toast0's graph that KCSM looks mostly okay since April 13.

This morning conditions are good with KTVU SNR 24 dB and KCSM SNR 20 dB. I see no issues with KCSM at 7 am.

BTW, you're saying that a Signal Quality on the HDHR of 50% will produce an error free picture?

Chuck
Yes, if the Signal Quality stays above 49% (50% and higher) then the picture and audio are fine. The HDHomeRun Config GIU is a live display but in reality must be an average over ~ 1 second. That is the same in the CMD window output I posted.

I found the following post to [HDTV-in-SFbay] when I signed on after 6 PM.

Posted by Hanns Ullrich <[email protected]********.***. I have not seen that name before but I have already reported a change ~ 12:12 PM. in Toast0's chart for RF 43.

Quote:
Looks like our exciter is acting up. No adjustments and no way to correct it manually.
Switched to back-up exciter. Toast0's chart looks better, not perfect. Give it a try and let me know if your reception is better.
Funny, we have a half dozen consume set-top boxes here (1st-4th gen ATSC receivers) and none of them had trouble locking on and receiving clean signals here in San Mateo.

-H
On Wed, Apr 11, 2018 at 6:27 PM, Stephen Fischer [HDTV-in-SFbay] <[email protected]> wrote:

Take a look at Toast0's chart for RF 43. It's nuts.

On my new HDTV from two years ago KCSM breaks up, only my newer HDHR
might work. Just barely.

I am in the process of sending a e-mail to KCSM.

After a week of a reported problem there appears to be nothing done.

TSReader report coming soon to AVS.

SHF

On 4/11/2018 5:59 PM, Larry Kenney [email protected] [HDTV-in-SFbay]
wrote:
>
>
> For the past week or so, I’ve found that it takes a precise setting of
> my antenna position to get a solid picture from KCSM. Their signal is
> bouncing all over the place if the antenna is in any other direction
> now, while they used to be solid in many directions. I’m 3/4 mile from
> Sutro Tower, zip 94114.
>
> Larry
>
>> On Apr 11, 2018, at 5:35 PM, Stephen Fischer[HDTV-in-SFbay]
>> <[email protected] <mailto:[email protected]>>
>> wrote:
>>
>> KCSM VC 60 RF 43 appears to have big problems, three reports on AVS
>> already, anyone have more bad reports and zip code please.
>>
>> TIA
>>
>> SHF

Interesting, the full transport stream capture is freezing after a few seconds but the picture and sound are fine.

Again something I have never seen before.

The transport errors and the missing packets are now at zero where they should be but the symbol quality is jumping all over the place, perhaps not affecting the picture and sound.

Opps, the GUI just showed the Signal Quality in RED (49% and lower for just a second).

SHF

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post #16495 of 18789 Old 04-15-2018, 08:29 AM
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Quote:
Originally Posted by SFischer1 View Post
KTLN intended to commence channel sharing on April 20, 2018, however, at least one MVPD has advised the Licensee that it does not receive a
good quality signal at certain of its head ends. Fiber must be installed.

That likely means KAXT will file also shortly and no WKRP on Me.TV for much longer than planned.

SHF
So no MeTV out of SF for awhile then? Sorry pal. I've worked a solution and am watching WKRP out of Sacto and the wife still has her usual stuff out of SF. I think Walnut Grove may have some other good channels that Sutro doesn't and maybe lacks some, still exploring.

Guess it's time for a more permanent installation..
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post #16496 of 18789 Old 04-15-2018, 12:27 PM
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Not seeing any problems with KCSM.
Always seems to work the last week I've been checking.
Is this an indoor antenna issue only?
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post #16497 of 18789 Old 04-15-2018, 01:25 PM
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Quote:
Originally Posted by 888CALLFCC View Post
Not seeing any problems with KCSM.
Always seems to work the last week I've been checking.
Is this an indoor antenna issue only?
KCSM is now on their backup exciter.

Better but Symbol Quality is still jumping all over. See Toast0's chart for RF 43.

Transport Errors and Missed Packets not good.

Outdoor issue for sure as Toast0's and my antennas both are outside.

Just compare the chart for KCSM RF 43 with most other Sutro stations and you will see the difference.

Watching the picture it pixelates and disappears at times with an unpredictable rate and sound the same.

But KTVU RF 44 has been the same since the leafs fell off the trees for me. Now they are growing back and I am hoping it will be back soon. I see that every year. Toast's chart of RF 44 is good.

As my captures of KCSM have dropped to zero so I cannot say it also is a tree leafs problem, maybe. But for Toast and other viewers, not likely.

I am using an indoor antenna pointed to the South East while RF 48 is actually to the North East to get KTVU.

SHF

http://ruka.org/~toast/atscdata/chart.php?c=43&s=&e=
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post #16498 of 18789 Old 04-15-2018, 08:08 PM
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Since KCSM switched to the backup exciter I see 100% signal strength (0 dBmV, -49dBm or greater) and 76% signal quality vs 65% (24.3dB vs 20.8dB, a full 3.5dB improvement). The signal quality and strength were steady both before and after the exciter changeover, and my HDHR4-2US could display the signal without trouble in both cases. I think the high gain and directivity 91XG aided in successful demodulation in spite of the problem signal. If your setup has less margin I would expect the degradation of signal quality would push you over the edge, as seems to be happening for some.

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post #16499 of 18789 Old 04-15-2018, 09:31 PM
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Quote:
Originally Posted by lifespeed View Post
Since KCSM switched to the backup exciter I see 100% signal strength (0 dBmV, -49dBm or greater) and 76% signal quality vs 65% (24.3dB vs 20.8dB, a full 3.5dB improvement). The signal quality and strength were steady both before and after the exciter changeover, and my HDHR4-2US could display the signal without trouble in both cases. I think the high gain and directivity 91XG aided in successful demodulation in spite of the problem signal. If your setup has less margin I would expect the degradation of signal quality would push you over the edge, as seems to be happening for some.
I wonder if the previous exciter repair (I discovered they were sending out a useless signal for 10+ days) might be a factor. Perhaps reinstalling the main exciter caused a problem that showed up later or with the tools at their hands not detected at all.

My knowledge of how the exciter signal is boosted up to the transmitter output level is non-existent. Just like I do not have any idea how microwave ovens work.

Remember, KCSM is operating on a shoe string budget, with out any shoes or string.

Now for the bad news, go back to my post and read the second link:

KCSM barely hanging on, Trump to decide or his flunky?

https://www.avsforum.com/forum/45-loc...l#post56021428

Read the story of how KRCB might or might not purchased KCSM.

Not a good read at all.

SHF
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post #16500 of 18789 Old 04-16-2018, 12:22 AM
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KCSM's signal quality has improved greatly here in the past few days... probably when they switched to their backup exciter. It still jumps around a little bit, but I don't see any pixelation or break up in their picture.

However, I'm still having serious remote lock-ups on my Sony on any of the sub-channels being transmitted on channel 28, whether it's their own, KOFY's, KMTP's or KEMO's.

My complete SF Bay Area DTV Station Lists: http://www.larrykenney.com/sfonair.html
Lots of Broadcasting links and information: http://www.larrykenney.com/broadcast.html
Live reception scans from my HD Home Run receivers: http://www.larrykenney.com/hdhr/
Photos and info on my antennas: http://www.larrykenney.com/tvantennas.html

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