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Wednesday, January 17, 2007

Binary Broadcasts: Feedback Further Flags My Confidence

Jan 17 2007 8:26PM | Permalink |Comments (5) |


I forwarded yesterday's post to KTXL's engineering department, and today I received a response that instigated a short email conversation. Unfortunately, my reception problem isn't yet solved, and as a result I'm even less confident that the NTSC-to-ATSC conversion is going to go smoothly for many over-the-air television viewers.

KTXL proposed the following possible causes for my reception problems

  • "I suspect you are using one of the Samsung SIR-T16X series receivers. This is a known software problem with them [editor note: no surprise to me]. Our station in Indianapolis experienced this problem and reported it to Samsung but they have opted to not try and upgrade the firmware in the receivers.... I believe the Samsung issue has to do with a buffer over run situation and it causes the signal strength to vary. In this case signal strength is based on a digital S/N approximation and not a RF level based reading."
  • "Perhaps you have a local interference issue or a suck out in your antenna. We have seen some issues with this added to the extra transmission line loss on channel 55 over 35 [editor note: the digital broadcast of KCRA, whose earlier-described reception was pristine at my location even though its antenna was within 1 compass degree of KTXL's antenna and was nearly 2 miles further away from me than KTXL's] and it can impact reception."
  • "We have also seen a couple of cases where a near by DirecTV dish can radiate a signal that causes a problem on channel 55."

They suggested the following fixes:

  • "I recommend the LG LST series receivers as they are more ATSC compliant than most and work well.... Try another receiver and see if that clears up your problem."
  • "The antenna that seems to be popular with the AVS crowd is the bowties in front of a panel. They come in 2, 4 or 8 elements with the 4 being the most popular. They are made by Channel Master and Winegard and are in the $25-$30 range. I use a 4 bowtie Winegard PR-4400 and it works great."

And, of course, they denied that their broadcast quality was at all to blame:

  • "We monitor the signal here on a number of different receivers and set top boxes and see none of these problems."
  • "If you look through the posts on the AVS Forum....you will see that there are very few complaints about our reception."
  • "I have a viewer in Nevada City that I call when I get a reception problem report and I talked to him a few minutes ago and he said everything looked great at his location.He does experience some fades but he is also is 80 miles from our transmitter near Walnut Grove and over the radio horizon."
  • "I live in East Sacramento and my son watched the two premier episodes of 24 and there were no reception problems at all?"

Let me be clear; I believe the folks at KTXL are broadcasting at peak signal strength. RF wasn't my specialty at university, so I'm curious to hear from more knowledgeable readers as to what might be causing my UHF channel 55 reception problem, especially at night...particularly given that nearby channel 53 (the digital broadcast of KVIE, the local PBS affiliate) is rock-solid. And it's a bit of a moot point because, as I pointed out yesterday, UHF channels above 51 are eventually going to get phased out by the FCC, with their spectrum redefined for other uses, via a plan known as 'Core Spectrum'.

But look at the fixes that KTXL proposes:

  • Buy a new ATSC receiver
  • Buy and install a new antenna
  • Dump DirecTV

They're not palatable to me, and I'm an early-adopter tech enthusiast with a higher-than-average household income. They certainly won't be palatable to the masses. And how would you feel if the ATSC receiver that your local broadcaster proposes you replace wasn't a several-hundred dollar discrete unit like mine, but instead was built into a several-thousand dollar HDTV?

I'll keep you posted as I learn more. And if any of you have suggestions for improved channel 55 reception that doesn't involve significant hardware retrofit (with unknown consequences to other local broadcasters), I'm all ears (and eyes).


Reader Comments



at 1/26/2007 1:19:05 PM, George95662 said:
I have been receiving ATSC for several years now from Fair Oaks. I am still using the (first generation) RCA DTC-100 tuner (as my primary ATSC receiver) and never had any problems with KTXL-TV. I am receiving ATSC from much farther than Walnut Grove (where most of the Sacramento stations' transmitters are located). My setup is an outside Radio Shack antenna, about 20 foot above my roof, with about 75 feet of RG-6 coax feeding into a winegard amplifier, delivering signals to about 12 or so outlets in my house. By far the most difficult signal to get thru is analog KTFK 64 from Stockton; but of course KTFK-DT 62 comes in perfect.

I know the Samsung devices are sub-par and I agree with KTXL that you should use a receiver such as LGE. ATSC receivers are fairly complex and the newer generation devices reduce or eliminate issues that plagued ATSC in the early years. This is not your father's TV. It is not magic. Rabbit ears and junk receivers will give you lots of grief. BTW, your problem could be a local source of RF from an unsuspecting source which will only show up as noise on an analog broadcast but will destroy digital reception. The source needn't be on channel 55; channel 55 may be a multiple of the source frequency. And newer generation receivers designed properly will filter/ignore those signals better.



at 2/8/2007 6:25:30 AM, Ken said:
You might need to amplify the signal from your antenna or you might need to attenuate it as it is too strong. It would help if you could get someone from the tv station who has a digital tv signal strength meter to measure the actual signal coming from your antenna. Try using an indoor amplified antenna that is placed on a high (near to the ceiling shelf) and move it around to orient it to the station. If there is a large structure such as a water tower near you point toward that and see if you can get a better signal via the reflection path than via the direct path.



at 2/9/2007 8:50:24 AM, dtv_guy said:
I suspect multipath interference. Buy a better receiver, like a Samsung DTB-H260F (~$175 from Best Buy). If it doesn't help you can just return it.



at 9/21/2007 6:58:15 PM, clueless_ILLINOIS said:
I have the same problem and I tried DTV_guys advice and it didnt help.

anything else I can try?



at 9/27/2007 5:23:48 PM, Bad advice said:
dtv_guys advice didnt work for me either

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