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Los Angeles, CA - OTA - Page 10

post #271 of 9442
Hey Robert or GF,
had a strange problem today, came home and my STB was saying "Reconfiguring Network" and it was like that all day. I had to unplug the unit to reset it and it looks like my San Diego KPBS stations have changed channels. They used to be 15 (analog), 15.1 (HD) and 15.2 (DT), now they are 15 (analog), 30.1 (HD) and 30.2 (DT).

Did your channels change for that station? I wonder if something happened to my STB?

Let me know what you find!

post #272 of 9442
I was having weird problems today also. I'll try to see if it was the PBS station. Yes they seemed to have changed to 30.1-30.2. I was having a hard time today, I must have spent an hour trying to figure out what the heck was going on. I was getting a signal at 15.1, but it wouldn't stay constant and was dropping out . Thanks for the post, I was having a time of it today.

post #273 of 9442
Wow, thanks for the post Robert. I probably spent 2 hours resetting, unhooking the antenna, rescanning, changing zip codes etc...man I thought I was going crazy.

On 15.1 and 15.2 I have a signal, but no picture..they are on 30.1 and 30.2...very strange.....I wonder what's going on?

It sure threw my STB for a loop...wonder if it will change back?
My DirecTV channel guide is now off, it shows the guide info for 15.1 and 15.2, not 30.1 and 30.1...kinds sucks...home one or the other gets corrected!

I will let you know if I see a change, please also do the same!

post #274 of 9442
The actual UHF channel used for KPBS-HD has always been UHF channel 30. Looks to me like their encoder data got reset yesterday, perhaps due to equipment overhaul. They need to re-entre the 15-1 and 15-2 PSIP info.
post #275 of 9442

Originally posted by ThumperBoy
The actual UHF channel used for KPBS-HD has always been UHF channel 30. Looks to me like their encoder data got reset yesterday, perhaps due to equipment overhaul. They need to re-entre the 15-1 and 15-2 PSIP info.

That was my thought since I knew the UHF was Channel 30, but I did not know if this was a permanent change or PSIP issue. Glad to see it was not just me...but my STB did not seem to adjust to the change very well...Sony HD200.

post #276 of 9442

Same for me..... I was actually playing with the STB trying to get XUPN and I lost the PBS channels. I quit around 6:30 or 7 and still didn't have them back at the time. Darn Fox is acting up again too. It doesn't want to stay constant. I'm thinking the wind is actually blowing my antenna around a bit, Fox improves while NBC goes bad and vice versa. Anyway.... are the PBS channels back to normal?

post #277 of 9442
fredwooch --

Yes, the 1171 is the right number but with this unit you will need to insert it before the first diplexer. That may be hard to do because of the power problem but it won't work if it is on the other end (between the second diplexer and the receiver...) because at that point it is also amplifying all the noise and multipath reflections.

For any amp to be effective, especially with digital signals, its input needs to be as close as possible to the antenna. In the case of the 1171, I've found it loses its effectiveness if the distance is greater than about 20-25 feet. "Preamps" solve this problem by separating the amplifier section from the power supply into a two-piece system. You mount the amp portion up on the antenna mast and the PS can be farther down the coax line where power is available. The PS section sends power back up the coax to the amp and passes the amplified signal through to the receiver.

The CM 7775 is the only preamp I've found with a low enough noise factor to work well with digital signals. The only problem is that it is not available locally. All of their "lessor" models, that you see at Fry's, Lowes, etc., are too noisy. Same with everything else available at Radio Shack except the 1171, which of course, is not a two-piece unit.

Unfortunately, I haven't found a set of diplexers that will pass the power back up the line to the amp portion of a 7775 so I don't think it will work for your present setup. You either need to run a separate coax line or run a low-voltage power line outside so you can use your 1171.

-- Gary
post #278 of 9442
Gary -

Thanks for the reply. If I understand you correctly, I've got two problems, then. First, the two-piece preamp that Radio Shack sells (the 15-1710) is too noisy to help in any event and the only two-piecer that would be effective, the CM 7775, is not available locally. Second, even if I could get the 7775, the diplexer will block the power from getting to the antenna-located pre-amp anyway. What a bummer.

I may try experimenting with different combinations before taking the more drastic route of sending yet a fourth cable into our bedroom. (We've already got two coming in from the satellite for our DirecTIVO, and a third for the High Def from the satellite. My wife is going to absolutely kill me if I try to send another one in through the wall.)

Is there any possibility that I can harm my system by hooking the amps or preamps up between the inside diplexer and the receiver, just to see if perhaps the extra signal boost, even with the added noise, can put me over the top on some of the now-marginal stations?

post #279 of 9442
I use the silver sensor indoor antenna and have been able to get all Los Angeles stations except for PBS, even though i have signal hill obstructing a clear path to mount wilson. The antenna sits right on top of my panasonic .
post #280 of 9442
Called KPBS in San Diego just now, it was their PSIP encoder that had to be rebooted, so the channels should be remapped back to 15.1 and 15.2 now!

I can't check it from work, but they were aware of the problem!!!


post #281 of 9442
Thanks for the gouge Tom. I'll try a re-scan when I get home!

post #282 of 9442
I confirmed KPBS encoder is back with 15.1 and 15.2 and correct time too.
post #283 of 9442

A simple coax question,if you don't mind. I have a 75 ft. run from ant. to family room. At the moment I'm using RG59. If I switch out to RG6 or better will I see a differance in performance?. Thanks

post #284 of 9442
I switched a 50 ft run of RG-59 for a run of RG-6 and was able to pick
up three more channels that I didn't before. This is without a pre-amp.
The RG-6 has lower resistance and won't degrade the signal as much
over a longer run.

post #285 of 9442
75ft of RG6 has about the same loss as 50ft of RG59, so you would cut the cable loss 1-2db.
post #286 of 9442

I switched out the rG-59 with the RG-6 yesterday. I got a channel on my San Diego side that I wasn't getting before KUSI 51.1. That signal is still to weak to watch. I also get a much better signal from NBC. On the L.A. side I am getting a much stronger signal from KCAL. Thanks for the input.

post #287 of 9442
Sounds like you could benefit from a good low-noise-figure preamp there robhair, since the preamp will amplify prior to the loss over the cable.
post #288 of 9442
I got this from Cox OC last week. It's probably old news.

Thank you for your inquiry. Cox is committed to providing the best
customer service possible.

We were informed back on April 23rd that our HDTV service will be
rolling out by the end of June if not before.

The article below ran in the Orange County Register's Briefing section
back on April 23rd (on Business page 2).

"Cox cable TV will offer high definition

Cox Communications, the cable-TV company that serves most of south
county, plans to introduce new channels using the new high-definition
broadcasting standard by the end of June. Customers will be able to
receive high-definition versions of KNBC, HBO, Showtime, ESPN and The
Discovery Channel. KNBC, HBO and Showtime will be provided at no extra
charge above what cable customers currently pay (you must be a paid
subscriber of HBO and Showtime to receive their high-definition
channels). ESPN HD and Discovery HD Theater will be packaged together
for $9.99 a month.

To receive the service, subscribers will need a high-definition
compatible television and a high-definition decoder set-top box. They
can rent the decoder box for $9.95 a month, which is $6.70 more a month
than the company charges for a regular digital cable box."

To work with Cox's first generation HDTV offering, your HDTV set or
monitor must support 1080i HD signals. Most new HDTV sets support the
1080i format. Refer to your owner's manual to determine if your HDTV
supports 1080i.""

We hope that we have been able to provide you with the information you
requested. If we have not, or if we can be of any additional service
to you, please do not hesitate to contact us again.
post #289 of 9442

I'm already using CM7775,without it I only receive one channel in each direction.

post #290 of 9442

Originally posted by robhair

I switched out the rG-59 with the RG-6 yesterday. I got a channel on my San Diego side that I wasn't getting before KUSI 51.1. That signal is still to weak to watch. I also get a much better signal from NBC. On the L.A. side I am getting a much stronger signal from KCAL. Thanks for the input.


Good to hear Rob! I am also using the CM7775, works well and I also get KUSI 51.1.

I do notice on NBC (San Diego- and CBS less often), I sometimes have receptions (Signal Strength) issues, I could be watching for an hour with 77% SS, then it drops to zero for a short while, it may not stay there long and does not typically bounce back and forth but will come back to 77% and I can continue to watch TV. Could this be a multi-path problem? or is it just part of life with OTA and weather conditions etc...?

post #291 of 9442
KNSD-DT (San Diego's NBC) is transmitting at a very weak power level - much,much less power than the other stations. So I would expect it would drop out and vary quite a bit with atmospheric conditions beyond about 40miles from the transmitter unless you are at a very high altitude.
post #292 of 9442
I do remember reading that NBC signal was on the weak side, and I think that is what I am seeing...

Thanks for the response!

post #293 of 9442
What you're probably seeing, Tom, is aircraft interference. As aircraft move up and down the coast, signals bouncing off their fuselages arrive in and out of phase with signals arriving directly or refracted through dense air layers. They'll add, then subtract, and so on as they move. Depending on the moisture and temperature clines present at any moment, the effect can be negligible or significant. The effect of reflections off of the ocean also vary over time because of the angle of refraction in upper layers--the "duct" effect.

This is where power helps. KFMB-DT (CBS) runs at 703kW ERP while KNSD-DT (NBC) is at 18kW, so you would more likely see the effect on KNSD. With everyone due to raise power next year, the fading should decrease at that time.

One solution would be diversity reception; i.e., a circuit would pick the best signal for the moment from two widely separated antennas. We did this for 35 years to pick up CBS microwaved over that famous long path from Mt. Wilson to Mt. Soledad. It worked...most of the time.

Of course, no maker that I know of makes a diversity HD receiver.
post #294 of 9442
So KNSD-DT(NBC) is only broadcasting at 2.5% of the power of KFMB-DT(CBS) - thats a huge difference!
post #295 of 9442
Thank you for your reply Gary, it was very informational!
It is amazing to see the difference in power output, no wonder I have very little issue with CBS' signal and they have all the good shows in HD anyway (am I kissing to much bootie now?) !

I did not really think it was a multi-path issue, but I live in a hilly area in South Orange County, but up on a hill top of about 1400' and was not sure if the signal was reflecting or giving my multi-path issues anyway.

PBS-DT and PBS-HD have been great, never an issue (except they have been having PSIP issue over the last week or so)

CBS, ABC and FOX are good about 95% of the time.

NBC seems like it may be good 70-80% of the time (but never at the right time!), seems like usually in the later part of the night.

All of these are San Diego channels, I get no LA channels due to a large hill in that direction.

Thanks again for your input Gary!

post #296 of 9442
Finally! I now have KABC from mt. Wilson. After 2 months of trying to get KABC i decided to try out my friends Silver Senor indoor antenna and what do you know, channel 7 pops right up. It drops out once in awhile but thats a lot more progress than what i was getting before. It may have to do with now my cable run is only about 20ft as opposed to 50 feet from my roof. But i still figured my outdoor antenna would be much better hence never thinking of trying out the silver sensor.
So now I have a Winegard 4400 and Channel Master 4228 bowtie antennas that i dont need. If anyone wants to buy them off me I would be willing to sell them at $25 each. email me at dlai@usc.edu and I live in arcadia.
post #297 of 9442
Aliso Viejo update.

Over last weekend I received and installed both a new HDTV card for my HTPC (a MyHD MDP-120 which replaced a MyHD MDP-100) and my preamp (a Channel Master CM-7775 replacing an RS 1171).

I replaced the preamp first. Signals improved by up to 15%.
Replacing the HTPC card improved signals by a further 15-20%.

Finally I'm able to watch ABC7 with no dropouts. Although I'm on the wrong side of the hill I'm able to receive all Mt. Wilson stations without dropouts, and I'm even getting (very low strength and unwatchable) signals from ch.19 and ch.25 from San Diego!

So - although my cable run is less than 40 feet I think if people are having signal-strength issues they should try the CM preamp.

The tuner on the MDP-120 is supposed to be 30-35% more sensitive than its predecessor. Although I've not seen quite this much gain it is definitely better at picking up weak signals, and is reported to handle multipath issues better. I also find that the card locks to the station more quickly and dropouts are rare even on the weakest channels.

I'm happy!!

post #298 of 9442
What type of antenna were you using AndyS?
post #299 of 9442

I started out with a Silver Sensor, but now I have dual RS 15-2160's horizontally stacked. Amazing value for money!!

post #300 of 9442
I have two Samsung SIR-T151 HDTV tuners, one that is unable to lock in on KOCE and KLCS. I get no picture or sound and a message of "Not in Service" when I try to manually add these channels.

I can receive these channels that I did a channel scan for earlier this month with the other tuner but only after about a 10 second delay when they were mapped to:

50-1 KOCE-DT
58-1 KLCS-DT

I have a non-amplified Zenith Silver Sensor antenna in my attic which delivers a strong signal for all LA stations, including these two, in my Lake Mission Viejo neighborhood. What could be wrong?
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