San Francisco, CA - OTA - Page 292

Thanks... I also added graphing for transport errors (and some other errors, which seem mostly pretty low, and I started collecting data from other Mt. Allison stations; rf 42 (KAXT 1) http://ruka.org/~toast/atscdata/chart.php?c=42 rf 49 (KTST 48) http://ruka.org/~toast/atscdata/chart.php?c=49 and rf 51 (KDTV 14) http://ruka.org/~toast/atscdata/chart.php?c=51

There are only a couple data points on those last three right now, but if you view it in the morning it will have an overnight. Next up, time filters and/or comparisons between channels.

Toast0... I've fowarded copies of your posts to Rich, the KGO Transmitter Engineer.

Larry

Since Chuck (Calaveras) posted his table of values comparing his results to the TV Fool results, I ran through all of the channels I can get here and logged the peak SNR dB value for each of them. I then compared my actual signal strength to what TV Fool provided for this location. The TV Fool results are pretty close to actual results for most channels, but there are a few exceptions.

I won't list all the values but will comment on the exceptions:

- - TV Fool shows KDTS 8 (52) from Mt. Diablo at the top of the yellow zone, but I barely get it. If it gets up to 16 dB SNR it's doing good. Most of the time it's below the cliff edge.
- - They show K02QO 2 from north of Santa Rosa right below KDTS. I've never seen a signal on channel 2.
- - They show the KPIX translator on channel 42 from Mt. Vaca as being on the air. I haven't seen that either.
- - Channels 22 and 68 from Sonoma and Marin counties are way down in the pink section, and channel 50 from Mt. St. Helena is down in the gray area, but I get all three stations with signals in the 26 to 29 dB SNR range. They should all be up in the yellow section. They're all much stronger than TV Fool predicts.
- - Finally, the signal strengths shown for the Walnut Grove stations don't line up with the strenghts that I get. They list the ones I receive in the pink section, except for KQCA which they show in the gray. They should all be in the pink, but the relative strengths don't compare to actual values. They show 10, 6, 13, 31 and 3, in that order, then 58 way down the page. I get 31 the best, by far, then 58, 6,13 and 10. I used to get KCRA 3 (RF35), but since KGO's translator came up on channel 35, I don't get it any more, nor KGO 35.

TV Fool must take the mountains and hills into consideration, otherwise the listings wouldn't be anywhere near to actual values, but their relative signal strengths for the more distant stations don't reflect actual values.

Larry

My experience here is the same that non LOS stations are somewhat stronger here too. +20db
But (Mostly UHF) there are antenna "dead zones" that bring much worse predictions -20db
Some tvfool YellowZone stations drop to zero in those areas.
It gives a good suggestion for DMA stations. Everyone here is talking mostly about tvfools "out of DMA area reception" predictions. And we see erratic results with those.
It also does not factor the channel 6 problems.
It predicts I receive that channel. (Not factoring in the FM levels here)
Analog tv 6 ? No. 87.7FM Yes
88.5 audio blasts on the tv 6
It will need some expensive high quality filtering here if that channel position ever goes digital. Or it seems it has been dropped for tv service to provide 1 additional fm station.? Waste of spectrum.

tvfool -vs- fmfool ..... And sorry channel 6

Tv fool predicts this for channel 6
NM +5.3 Power Dbm -73.5

And Fmfool predicts this ... ( That shows up on channel 6)
Problem ... 88.5FM example (And some others)
110 Kw
-21.3 Rx Dbm

I do not see the analog picture with these signal levels.

Then you have to wonder how useful TVFool really is. If you have LOS between the antennas then reception is virtually guaranteed. If you have one or two edges then you'd really like a more accurate estimate to judge whether it's worth investing your time and money into trying to receive the stations.

I also discovered that TVFool doesn't take into account the vertical radiation pattern which can be extremely important in some situations like here in the foothills where many people are higher than the transmit antennas and the vertical lobe of the transmitters tilts down.

Chuck

There's a difference. Across hilly terrain, the predictions are pretty good. Across sharp mountain ridges are where it becomes an issue.

Nobody takes into account the vertical radiation pattern because the FCC doesn't make it readily available. I've been on and off hand-entering vertical pattern data into the RabbitEars database, and I cannot locate those patterns for all stations. It's not a fun process, and as a result I haven't touched it in a few months.

The prediction model the FCC uses is Longley-Rice. It's the same model TV Fool uses, the same model RabbitEars uses, and I imagine the same model most everyone else uses.

- Trip

Honestly, I don't know how you tell the difference between the two. It would seem to me that a ridge is a ridge.

I know. I dug up the vertical patterns for the Sutro Tower stations because I wanted to know how much power each station had at the top of Mt. Diablo which is in line with my location. Turns out there was a high degree of correlation between the highest ERP and which ones I receive here. I had to search to find the original DTV application to locate each vertical pattern. On top of that many stations are using antenna models that are obsolete. It's a royal pain. I wouldn't want to do it for the whole country. But not readily available doesn't mean it's unimportant.

I understand that it's SOP but that still leaves many with highly inaccurate predictions. It makes me very wary about telling anyone what stations they can or cannot receive.

Chuck
Edited by Calaveras - 6/27/12 at 5:53pm

New sub-channel spotted today: KTLN 68-2 labeled "CRTV". So far, all I've seen is infomercials, but I haven't watched it much.

Larry

potential good news fort anyone who misses accuweather and or nbc weather: theres a message for comcast subscribers that there will be a new KRON weather channel , slated for ch193, in the same channel group as the rest of the local OTA subs so....

i reckon we'll be seein this on ch 4.whatever.

I saw one too. It was KPOP. I believe it was 32-6. I couldn't decode the A/V. I should have quoted Larry, but hit the wrong link.

Hope I'm posting in the right section forgive me if I'm not. I recently moved to a new apartment in the Outer Richmond district and decided to go with OTA TV. I used some generic indoor antenna and was picking up most of the local channels no problem. A couple of them here and there would require some turning and adjustment. I decided to pick up a better antenna to pick hopefully pick up some more channels and require less adjustment on my part. I picked up a Winegard SS-3000. I'm pretty pleased with the results. All the channels I was having problems with before are now coming solid. There's only one channel that I want but can not tune in for the life of me and that's 26.x KTSF (I wasn't getting this with the original antenna either). I moved the antenna from the middle of the room to the window where I have a clear line of site straight to Sutro tower. I know KTSF is being broadcasted from the San Bruno mountains which is slightly to the right of mount Sutro from my apartments location. I'm on the 3rd floor which is higher than most of the buildings in my area so I don't think there's anything blocking me. I pick up KNTV 11.x which is also being broadcasted from the San Bruno mountains. I'm getting almost 100% signal from them or so says the signal indicator on my TV a Sharp Aquos LED. I can't figure out why I can't get KTSF. Does anyone have any ideas what it could be?

Here's the info from tvfool that I've pulled up.

Skurzhun,

Have you tried raising or lowering the antenna a couple of feet at a time. Very specific height may be needed. That's something I've experienced indoors here.

Do you get 65.1?

Deltaguy,

I don't get 65.1 either. I've tried different heights from the floor to almost all the way to the ceiling. I still get 0% signal on 26.1 and 65.1. I'm guessing in my location I have to be even higher up to get those channels. I can't even get a hint of signal from those channels. Yet 11.1 is rock solid.

Hi,

KNTV RF 12 PSIP 11 is high VHF so that may be the difference.

KTSF and KKPX are 2Edge so they are very dificult for you to get. (RF 26, RF 41)

Try entering your exact location and antenna height into:

TV Fool Google map
http://www.tvfool.com/?option=com_wrapper&Itemid=90

Click on "Show lines pointing to each transmitter" and then zoom out.

Your exact locatation gives a much poorer TVFool than just your ZIP code.

More hight might help, but if you are on the beach

SHF

You probably have plenty of signal being so close but with a 2 edge path (2 hills to refract over) and many buildings acting as reflectors you probably have plenty of multipath too. There's no easy explanation why sometimes you'll get some stations from a transmitter site and not others in such a situation. There may be nothing you can do within reason from an apartment to get those stations. Consider yourself lucky that you're getting KNTV.

Chuck

Not quite at the beach.

Ah well that's disappointing. Thanks for the info. Maybe I'll give it another shot today re-aiming and seeing if I can get some sort of signal.

Decided to work a bit on the graphs tonight; added a drop down beneath the graph to set the channel, as well as two boxes to pick start and end date (if you have a fancy browser, these should be html5 date pickers, but I haven't tested that yet).

Interesting find, it looks like something happened to rf 7 on the 15th starting between 2:30 and 2:45 am; I measured signal strength way down and was not able to lock, this was resolved between 4:15 and 4:30 am chart for rf 7 during the same time period, rf 35 was doing interesting things. chart for rf35 Based on the PSIP info, it looks like it started repeating KRCR (rf 7 from Chico/Redding), with good signal to noise ratio, but lots of crc errors and missed packets (doesn't seem to make sense?)

Seems like an antenna on Mt. Allison pointed at Mt. Sutro shouldn't pick up KRCR? but I guess having an antenna up that high is bound to pick up a lot of things?

KGO 7 goes off the air once a month in the wee hours of the morning for transmitter to studio link calibration and other technical stuff. That's probably what you saw. I don't know about other stations, but they might do that as well.

Interesting that the KGO 35 translator receiver picked up KRCR when KGO was off the air. That's a long haul to Redding!

Larry
SF

KTLN has added SBN programming on 68.3.

Chuck

Yesterday I watched KGO's transmission of the British Open. The dropouts would be intolerable to all but the most devoted fan. I stuck it out. I had to suppress my wanting to contact the station and complain (which I've never done for any TV station). However, I was certain I was going to do so after finishing watching my DVR timeshift of this 3 hour event. I called and left a VM for the station manager (I know that it will probably not get past an underling), and also left an "email" at their site, which went thus:
- - - -
I used to receive your station fine with my rooftop antenna and HDTV computer card. However for 3 months or so, I get almost constant dropouts. The signal is very weak compared to all the other major bay area stations. The signal goes to 0% frequently. I'm finding the British Open to be unwatchable 80% of the time. I'm in the flatlands of Berkeley. I get all the other major bay area stations fine, get KNBC consistently at 100% signal strength. Only occasionally do I get to see 15 consecutive seconds of KGO TV without blank screens, usually no more than 4-5 seconds if I'm lucky. On the AVS Forums Bay Area OTA thread they say you've been having issues with the transmitter tower. I wish you'd do something about this. Evidently, you guys don't think it's a priority. You must realize that there are a lot of people around who don't have subscription television. Please honor that public. Thank you.

If you're in Berkeley you're not receiving KGO on RF 35 which is what all the discussion has been about. You're receiving them on RF 7. Their channel 7 transmitter on Sutro tower is not having a problem. I'm sure you don't want to hear this but the problem is with your setup. I'm 110 miles from Sutro and I've seen nothing unusual with KGO 7 the last 3 months. If KGO was dropping out every 15 seconds this forum would be inundated with complaints and you don't see that here. Unfortunately I don't know what is going on with your setup and troubleshooting these things over an internet forum is hard.

You can try all the standard stuff like checking connections or trying another TV, but since you receive KNTV fine, maybe you have some sort of local interference on channel 7. One thing you can try is to take your computer to another location with a small antenna and see if the problem goes away.

You should be able to receive KGO in Berkeley with an outdoor antenna if they were running only 100 watts. Your issue is not signal strength but something else. The hard part is determining what the something else is.

Chuck

My question to Muse is... What kind of antenna are you using? Is it designed for VHF? If you're using a CM4228, that is NOT designed to receive channel 7, even though it does a better job than most UHF antennas. It only works for the very high VHF channels, 10 to 13, any distance from the transmitter site.

As Chuck says, there's been nothing wrong with KGO's signal on channel 7 for ages.

Good luck!

Larry
SF

Myself and other board members in the south bay certainly have been reporting reception problems with RF7's signals

at my location the reception problems coincided with the arrival of KGOs translator RF35 on mt allison, this past winter, the time of year we typically see our best RF reception from SF, not vice versa

members like larry and chuck would be able to explain this much better than I, but its my basic understanding a broadcast transmitter can send varying amounts of power across the compass, in other words, just b/c there are no signals problems in one direction, doesnt mean there are no problems in all directions

shortly after larry filled us in that KGO was tending to the problems on mt allison, their RF7 signal down here has improved SIGNIFICANTLY down here, going from being viewable to 40% of the day to 90% of the day

having been affected and following it closely, its seems to coincedental to me for there not to have been issues with rf7's signal in our direction

CTEL08...

It's got to be atmospheric conditions that's affecting your signals. KGO has made no changes to their antenna and is still putting out the same power as always.

I have no other explanation for the change in signal levels down your way.

Larry

Coincidence.

The KGO 7 antenna is omni directional circular polarized. There is no way to change the amount of power radiated in any direction. Real changes in signal strength can be completely attributed to varying atmospheric conditions.

The last couple of days KNTV has been in here every time I checked it which is highly unusual. At the same time everything from Sutro has been up and down. Over the last 90 minutes KGO has been rock steady at 24 dB SNR. This morning I was receiving no stations from Sutro.

I suspect that in the analog days changes in the signal weren't noticed as much since the it didn't completely disappear and hardly anyone would remember what the picture looked like weeks or even days prior.

Chuck

Edit: Larry beat me to the punch but I see we agree.

I believe the antenna is a Winegard Chromstar II Ghost Killer VHF/UHF Model CS-7210 that I bought from Lasher's Electronics in Berkeley and installed myself some years ago, probably around 1990, when I was having ghosting issues with my analog TV. It solved those issues. It's installed on a mast above my roof, and it's a 2 story house. There are no taller buildings around and I'm a good 1.5-2 miles from the Berkeley hills, which are the other direction from Sutro Tower. I believe I have a straight shot at Sutro tower, and the antenna's pointed right at it. I determined from maps the direction it needs to be to point at Sutro. I haven't changed the wiring in a long time, but AFAIK it's fine and like I say I get KNBC at 100% signal strength consistently. Other stations are not that strong according to my MyHD application, and it's been that way since I started using the MyHD HDTV card, but I've never had problems with stations dropping out much less going to 0% signal strength repeatedly except for Channel 7 KGO TV the last few months. It's truly unwatchable. My post above complained about Saturday's British Open broadcast of 3 hours, but Sunday's was quite a bit worse. To say it was horrendous would be a gross understatement.

Right now KGO-HD D0-7.1 is showing signal strength varying between 0% and 18%.

D07-2 (07) LIVWELL and D07-3 (07) LWSD have similar dismal signal strength. My other stations are showing typical signal strength of above 75% and I'm having no apparent difficulties with any stations except KGO. I took my card out of favorite channel mode and checked every station that was just auto-scanned using that antenna. Only the 3 KGO stations and showing low signal strength. Indeed they are often showing 0%, "No Signal." ATM, anywhere between 0% and 32%.

What do you suggest?
Edited by Muse - 7/23/12 at 7:53pm

Replace everything. I guarantee that any antenna that has been up in Berkeley for 22 years is very corroded. Who knows what the issues with it is. I lived in Fremont for 18 years and anything metal outside corroded fast. It has to be worse in Berkeley. 22 years is a good life for a TV antenna.

When you say "signal strength" I assume you don't mean Signal Quality. You're only 12 miles from Sutro tower and you say you are LOS so every station should have a signal strength of 100%. There have been other instances reported here of antennas that appeared to be intermittent on only one channel. It could be intermittent on other channels but not bad enough to cause dropouts.

Chuck

a coincidence lasting many months and thru 3 seasons and sets of conditions?

i seem to remember that it was reported that the signal to mt allison from sutro (the same general direction, being south) was barely strong enough to pick up an acceptable signal to be retransmitted. if people over 100 miles away in one direction are receiving RF7 but less than 30 miles, LOS and over water in the other direction is borderline, something was up beyond just coincidence.

Muse... Sorry, I don't have any better suggestion than what Chuck offered. Something has gone bad in your antenna system OR you're getting multipath from something that is wiping out your channel 7 signal. No signal should make drastic changes like what you're seeing where the signal drops to 0. Whatever is the problem is local to your setup.

Go to Radio Shack, Target or some store that sells inexpensive indoor antennas. Buy one and see what you get with that. You might be surprised.

Larry