KRMA signal update: Panorama: Rocky Mountain PBS

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KRMA signal update

posted Wednesday, Aug. 26, 2009 1:09pm

See more on: Tech Talk

KRMA will be operating at low power for the next 30 minutes due to transmitter maintenance. Thank you for your patience.

What's your point of view?

John Anderson, CTO
Wednesday, August 26, 2009 › 1:16pm
KRMA will be at low power this afternoon from aprox 12:45 until 1:30. We need to do some required maintainence on the New Transmitter. This is rather like the first break-in maintenance on a new car. This brief interruption will allow us to keep every thing working perfectly and continue to provide the great signal that has been on since August 10.
Thanks for understanding.

John Anderson, CTO

Pete
Wednesday, August 26, 2009 › 7:34pm
What happened today (8/26) 18:35 to 1900? It was off the air for me. (just nw of Niwot). Back on at 1900 with good signal again. Lost a bunch of the Newshour.

steve
Sunday, September 6, 2009 › 4:54pm
I live downtown by city park and can't channel 6 over the air at all anymore. I was getting it great till recently and now it's gone. Did something happen?

Ed Marvin
Monday, September 7, 2009 › 8:36pm
Our CH6 signal has been intermittent (visual & audio) for about the past 2 months; maddening breaks in great shows.

Other Bresnan cable channels here in G.J. are normal. Any ideas?

Adria Lucerna
Tuesday, September 8, 2009 › 2:08pm
We just purchased yet another, supposedly more powerful, antenna to try to receive channel 6. It has 360 degree reception and we have tried it in MANY locations throughout our house. We still don't get any pbs stations. I'm tired of buying new equipment only to find nothing works. What should I do now? We live in a location that we can clearly see the towers and the "lighted cross." I'm frustrated and tired of dealing with this issue. Thanks for your help.

Susannah
Tuesday, September 8, 2009 › 3:41pm
To Adria Lucerna:
RMPBS is currently broadcasting digitally from Mt. Morrison (39º40'17.00" N Latitude 105º13'6.00" W Longitude) not Lookout Mountain. Our digital signal is currently at full power (1Mw). The signal has been at full power since August 12th. If you have rescanned and get no signal from Rocky Mountain PBS, you should try a "double rescan". This may resolve a problem where a DTV TV tuner does not properly scan for the new channels. Disconnect the antenna from the DTV TV or DTV converter box, and then perform a rescan (this clears the channels memory). No channels should be found. Then reattach the antenna to the DTV TV or DTV converter box. Then rescan. Now you should have a completely new programmed memory of channels.

Susannah
Tuesday, September 8, 2009 › 3:42pm
To Adria Lucerna:
You can also look at antenna options and positioning at www.antennaweb.org. There is also a lot of troubleshooting DTV information at www.dtv.gov.

david weir
Thursday, September 10, 2009 › 9:07pm
I have been getting good signal for a few months now. But for the last two nights I have been getting bad or no signal. What is going on? 9/10/09

Kevin
Friday, September 11, 2009 › 7:56pm
I live near downtown Littleton in clear view of the towers on Lookout Mountain to my northwest and, up until about 4 weeks or so ago, I received a superbly strong signal (via a new indoor HDTV antenna, connected properly to a brand new HDTV) from KRMA. Then, literally overnight, the signal degraded *significantly,* and has remained terrible ever since, despite numerous re-scans.

If I walk across the room, the signal breaks up and disappears; sometimes, merely just moving my hand or foot causes it to break down. Passing cars now also degrade my Channel 6 signal constantly.

It's made my viewing experience miserable. If something can't be done -- soon -- I'm simply going to give up watching KRMA forever. I'd really hate to do that.

I didn't change anything. What happened?

Cindy
Friday, September 11, 2009 › 8:38pm
We too have had a sudden loss of signal on Channel 6 in the past 2 days. It was excellent for us these past several months and then overnight simply gone. Auto rescan (as suggested above) has eliminated it from our lineup and manual scan shows it has bad signal strength. What a loss! We miss you. Please troubleshoot and post a solution.

Director Of Engineering
Saturday, September 12, 2009 › 5:59pm
Kevin,
Thanks for writing with your comment.
Here is what's happening, 4 weeks ago on Aug 10 we increased power and went to a new antenna on Mt. Morrison. Like you I live in Littleton and when we increased power I had the same issue. The cause of the problem is actually too much signal getting into your TV! If your antenna has a plug in "wall wart" power supply; try unplugging the wall wart. If the signal still is degraded, pick up a 10dB pad (signal attenuator) and connect that to your antenna input between the antenna and the TV. Then do a "double rescan" and that should clear up your problems.

Adria Lucerna, you might also try this same solution.

Often with DTV receivers LESS is Better than more!

John Wm. Anderson
CTO, RMPBS

Director of Engineering
Saturday, September 12, 2009 › 6:15pm
Refering to my previous post:
Since we are now at Full Power of 1 million watts to most recievers that is a huge increase in power from our previous 315,000 Watts. If you have a direct line of sight to Mt. Morrison and are close in you very well may be in a situtation where the strong signal is arriving with a strong reflection from a near by building (house, school, apartment complex) this may create a situation where your reciever can't discrimanate between the good signal and the reflection, (in analog we called it a ghost) so if you decrease the amount of signal going into the receiver (TV) it will allow the set to more easily select the desired signal, and very often you will actually improve your reception with a smaller antenna.

John Wm. Anderson
CTO, RMPBS

John Daigle
Sunday, September 13, 2009 › 8:27pm
Will the new power improvement change the ability of folks to tune their car radio into 87.1 to hear the FM portion of RMPBS?
I really miss this feature which seemed to go away several months ago. At night RMPBS is about the only thing worth listening to on the car radio!
Thanks
John in Evergreen

Director of Engineering
Monday, September 14, 2009 › 8:51am
Re: John Daigle's post;
Even if we continued to broadcast KRMA on RF channel 6 (our transmitter now operates on RF channel 18) you would not hear any audio since there is no analog FM component to the digital signal. In DTV the audio is a stream of bits that is embedded within the program stream along with the picture information and then decoded in your reciever.
When we stopped broadcasting in analog that "happy accident" ceased forever.

John Wm. Anderson
CTO, RMPBS

Paul
Sunday, September 20, 2009 › 2:49pm
I can't figure out how this list works. Where do I go (in URL space) to initiate a new topic? Why should I have to ask a stupid question like this?

Webmaster
Monday, September 21, 2009 › 7:47am
Paul, you can't start a new topic but if there is something else you'd like addresses, please contact us here: www.rmpbs.org/contact

steve
Monday, September 21, 2009 › 8:26am
I've tried everything suggested here, and the only TV I get channel 6 on now is the old 12 inch tube tv with a converter box. Since I rarely watch that, I guess channel 6 is gone for me. Too bad.

Cheryl Signs
Tuesday, September 22, 2009 › 7:19pm
I have comcast. I had 3 RMPBS channels - regular, spanish, & create. I had to rescan because I'd lost some other channels. Now I can only get 1 RMPBS channel even though I've rescanned in every mode. Is there a way to get the other 2 channels back?
Thanks

Eric
Wednesday, September 23, 2009 › 11:27pm
My friend who lives in Wash Park hasn't been able to get a KRMA signal at all since you switched to "full power" last month. The double rescan doesn't help. She's in an apartment building and just uses the TV's rabbit ears for an antenna -- not likely to be overloading the digital box. What could be the problem?

Eric
Tuesday, September 29, 2009 › 8:45pm
...anybody there?...

Tom
Tuesday, September 29, 2009 › 8:52pm
I live in Genesee. I have a clear view from my house of all the towers on Lookout Mt., less than a mile away. Yet I have not been able to get KRMA for years. Where is it? What does it take to get "channel 6?" I don't have cable. I have Dish network but don't subscribe to their local channel service. Via converter box I do get about 30 different HDTV channels over the air, from as far away as Cheyenne. Where is your tower hidden?

GE
Tuesday, September 29, 2009 › 9:03pm
Tom, KRMA Channel 6's DTV signal (RF18) is broadcast from Mt. Morrison, south of Lookout Mountain and above the Red Rocks Amphitheater.

KRMA's analog signal was broadcast from Lookout Mountain. Per the national full power DTV transition, their analog signal was turned off on July 12, 2009 (they were in "nightlight service" from 6/12/2009 thru 7/12/2009).

Tom
Wednesday, September 30, 2009 › 7:05am
I have rescanned and updated our DTV channels many times since January when we got the converter. I never got Channel 6. Last night I did "update" again and when it was done I entered "18" for the channel and was taken to channel 6! Now I have channels 6-1, 6-2, 6-3. At last. I have no idea why it didn't work before or why it does now, but I'll enjoy it while I can. Thanks.

GE
Wednesday, September 30, 2009 › 9:06pm
Tom, I suspect that at your location for some reason you are not receiving the embeded PSIP signal in the DTV signal which identifies the "virtual" channel that you are watching, i.e., virtual channel 6 being broadcast on RF 18. That may be because of a multipath interference distortion or problem.

One of the great things about the ATSC DTV signal is its ability to minimize multipath interference allowing one to see a perfect signal.

In any event, I'm glad your receiving the KRMA now. Also, you might retry the scan and see if you can capture the PSIP signal information. If you do, 6.1, etc., will appear on 6.1, etc.

Eric
Sunday, October 4, 2009 › 7:05pm
...Seriously: would anyone care to answer (notice?) the question I asked on 9/23?

Linda in Viewer Services
Monday, October 5, 2009 › 11:58am
To Eric:
Is your friend's antenna on the west side of the building, near the wall? That will help.

Multipathing could explain the problem. If she gets one signal directly from the transmitter and another copy of the same signal bounced off a wall or something the two might cancel each other out. The remedy is to very, very slowly turn the antenna, with frequent pauses, until a picture shows up. This could be any direction at all. Please try this and let us know if it worked.

GE
Wednesday, October 7, 2009 › 11:30am
To Eric & Linda

Linda's solution to the potential problem is incomplete.

If the problem is multipath interference and a signal cancellation has occurred, then the DTV converter box or digital TV must be rescaned for new channels, i.e., reprogammed, after each antenna reposition since you have already rescaned with negative results.

You can not just simply rotate the antenna without rescaning since the channel memories have likely been cleared of the previous channel 6 signal data during the previous rescan(s).

I have noticed there have been several blog complaints posted about signal problems in the Washington Park area since KRMA went to full power. That could be a null problem in the transmit antenna. Perhaps KRMA engineering can take a look at these reports.

Eric
Thursday, October 15, 2009 › 11:35pm
To Linda:

Thanks! Getting a better antenna (with a UHF loop) probably helped, but moving it ~6 ft closer to the west wall/window was the crucial trick. (Why?) Signal strength isn't super but channel 18 is now received as 6-1.

To GE:

We had no problem because we didn't use rescanning at all. I knew the actual UHF channel (18) already, so we just selected that manually, adjusted the antenna until we got a usable signal, and then added the channel to memory.

GE
Friday, October 16, 2009 › 11:42pm
Eric, I'm glad you got your friend's signal problems with channel 6 improved. Linda's solution worked due to an increase in signal level which is likely due to more signal level from adding the UHF antenna and more signal level being received through the window path and wall and/or placement resulting in less multipath interference (again resulting in an increase in signal level).

Most likely, RF18/V6 (RF=actual radio frequency channel #) (V=virtual channel #) was previously programmed in the memory so no rescan was required. 18 shows as 6.x (x should be 1,2,3 or 5, i.e., 4 channels) because of the capture of an embeded data signal in the DTV signal known as the PSIP signal that defines the virtual channel #. If you are not receiving all four channel 6 sub-channels, try a rescan.