[opendtv] Re: Tentative Channel Elections
- From: Tom Barry <trbarry@xxxxxxxxxxx>
- To: opendtv@xxxxxxxxxxxxx
- Date: Fri, 07 Oct 2005 23:16:25 -0400
Benham, Cliff wrote:
> WBBM-DT on Channel 3 in Chicago continued to generate a lot of
comments, =
> including some from CBS engineers. The two big problems people
mentioned =
> when talking about low VHF reception were picture break-up due to =
> impulse noise and the need for a large outside antenna.=20
>
I maybe mis-remember but I thought CBS 3 in Chicago also had major
interference problems with cable users connecting their sets via Channel
3 by RF F-connector. IIRC seems they made some compromise for 8vsb
cable carriage for awhile or something because of this. But my memory
is fairly hazy here and I don't live in Chicago.
- Tom
> I went looking for 'Linx Testing' and found this after reading the piece =
> for the previous month:
> =20
> From: RF Technology: Doug Lung =20
> TV Technology 08.04.04
> http://www.tvtechnology.com/features/On-RF/f_Choosing_a_Final.shtm
> "Some channels can be eliminated immediately. [snip] Channels 2 through =
> 4, and likely Channel 5 as well will not be suitable for DTV in most =
> markets due to antenna size and electrical interference. Channel 5 may =
> work better, but if broadcasters avoid other low VHF channels, there may =
> be little incentive for people to erect antennas for Channel 5. Channel =
> 6 will probably be unsuitable for DTV in most areas due to FM radio =
> interference.
> [snip]
> WBBM-DT on Channel 3 in Chicago continued to generate a lot of comments, =
> including some from CBS engineers. The two big problems people mentioned =
> when talking about low VHF reception were picture break-up due to =
> impulse noise and the need for a large outside antenna.=20
>
> Jim Steffey, director of engineering for WWMT-DT, Channel 2 in =
> Kalamazoo, Mich., said that even though the station is operating at its =
> full authorized power, "During thunderstorms, the signal becomes totally =
> unwatchable with frequent pauses in the audio and heavy pixelation and =
> picture freezes."
>
> Power line noise is also a problem. He noted that upper VHF and UHF DTV =
> stations in the same market can be received "without any trouble at all, =
> with not much more than a coat hanger for an antenna."
>
> [snip]
>
> Larry Davis, the transmitter supervisor at WBBM-TV/DT, said that the =
> signal is receivable in the market, provided you have an outdoor =
> antenna. The need for an outdoor antenna to receive low VHF when an =
> indoor Silver Sensor works fine on the other channels is a problem.=20
>
> [snip]
>
> Pete Putman, a DTV consultant who has a wealth of information on his =
> Web site at http://www.hdtvexpert.com said low VHF DTV is not a good =
> idea due to impulse noise and e-skip.=20
>
> [snip]
>
> Philip Smith wrote to mention problems he was having receiving WBBM-DT. =
> At 46 miles from downtown Chicago where WBBM has its antenna, his =
> reception using conventional antennas was similar to the others I've =
> mentioned. What I found interesting was his experience with a USB-2.0 =
> based DTV tuner and a laptop.=20
>
> I've always wanted one of those to check out DTV reception as I travel =
> from market to market. However, the electrical noise from the tuner and =
> computer seemed to be creating RFI (radio frequency interference) that =
> interfered with low VHF DTV reception. The USB 2.0 tuner is made by =
> Sasem in Korea and is supposed to use the "latest" LG Electronics =
> (Zenith) 8-VSB demodulator chip. More information is available at =
> www.sasem.com =20
>
> =20
> This is about the only piece I could find on low VHF DTV.=20
> I think some more testing needs to be done over the next 2 years=20
> =20
> ________________________________
>
> From: opendtv-bounce@xxxxxxxxxxxxx on behalf of Mark Schubin
> Sent: Fri 10/7/2005 9:55 AM
> To: opendtv@xxxxxxxxxxxxx
> Subject: [opendtv] Re: Tentative Channel Elections
>
>
>
> I think WBBM-DT in Chicago (channel 3) was part of the Linx testing.
>
> TTFN,
> Mark
>
>
> Benham, Cliff wrote:
>
>
>>I don't recall reading anywhere that testing of 8VSB DTV at low VHF =3D
>>frequencies has been done, or if it has,
>>what the results were. We have all read about 8VSB/COFDM testing that =
>
> =3D
>
>>was done at UHF frequencies, but
>>where are the test results for 8VSB at low VHF? This seems to be an =3D
>>accident waiting to happen, and one that=3D20
>>in the Philadelphia area will be bad both for ABC and all the =3D
>>disenfranchised viewers the day after analog shutoff.
>>
>>________________________________
>>
>>From: opendtv-bounce@xxxxxxxxxxxxx on behalf of Manfredi, Albert E
>>Sent: Thu 10/6/2005 4:28 PM
>>To: opendtv@xxxxxxxxxxxxx
>>Subject: [opendtv] Re: Tentative Channel Elections
>>
>>
>>
>>Cliff wrote:
>>
>>=20
>>
>>
>>>A channel 6 rabbit ear antenna is about 60 inches
>>>wide. At my house I would have to set the antenna
>>>direction so one 'ear' is sticking about 3 feet
>>>out into the living room and the other into the
>>>hallway right at 'eye height'.
>>> =20
>>>
>>
>>Cliff, I want you to know that I groaned when I saw
>>that WPVI (Phila) decided to go back to their VHF
>>Channel 6 allocation. I groaned because I remember
>>how you worried someone might use VHF for DTT.
>>
>>Hey, for Channel 6, maybe you can use one of those
>>Radio Shack "use your house wiring as an antenna"
>>gizmos.
>>
>>Bert
>>
>>
>
>
>
>
>
> ----------------------------------------------------------------------
> You can UNSUBSCRIBE from the OpenDTV list in two ways:
>
> - Using the UNSUBSCRIBE command in your user configuration settings at
> FreeLists.org
>
> - By sending a message to: opendtv-request@xxxxxxxxxxxxx with the word
> unsubscribe in the subject line.
>
>
----------------------------------------------------------------------
You can UNSUBSCRIBE from the OpenDTV list in two ways:
- Using the UNSUBSCRIBE command in your user configuration settings at
FreeLists.org
- By sending a message to: opendtv-request@xxxxxxxxxxxxx with the word
unsubscribe in the subject line.
Other related posts: