Walter's Telephones [Telecom]

>> The audio portion of TV's Channel 6 was receivable on any FM >>> radio, either cheap ones or good ones, tube or IC, for >>> _decades_. > >> Well, it's gone now, and it shall remain so for decades to come. >> Get used to it. > Not according to the newspaper. Apparently, surprisingly many people > miss it and they're looking into bringing it back.

Has the newspaper reported what WPVI's owners think about this?

> I don't recall anybody saying that. It would not cause interference >> to other FM stations. However, it would certainly interfere with >> WPVI-DT's signal. > I don't understand. Several things suggest to me the digital and > analog used _different_ frequences. (If in fact digital is using the > same frequencies, yes, of course the issue of is moot.) > 1) Before the digital switchover, TV stations were broadcasting in > _both_ digital and analog. They would have tests pre-cutover where > they'd tell viewers they were temporarily cutting off the analog > signal. If the viewer could continue receiving, the viewer was set > for digital, but if not, the viewer was not ready.

The FCC assigned every full-power TV station a temporary digital channel for the transition. WPVI-DT was on channel 64 during the transition. When the transition period ended, each station could choose to remain on its temporary digital channel, or move back to its original analog channel. WPVI-DT's owners chose to move back to Channel 6.

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> 2) Further, I thought (as stated by others) that the digital signals > were using different frequencies because the old analog ones were > to be reassigned to other uses, such as public safety.

Generally true, but exceptions were allowed in certain circumstances. I'll defer to Garrett Wollman to explain these exceptions.

3) The newspaper article (admittedly not a technical document) > suggested the problem was legal, not technical. Apparently dealing > with royalty payments. They weren't issue when it was a 'quirk'.

Had WPVI-DT remained on Channel 64, there would have been all sorts of legal problems associated with any attempt to resurrect WPVI-DT audio at

87.75 MHz, and copyright royalty payments no doubt would have been one of them. However, as you note, Disney's decision to move WPVI-DT back to Channel 6 has rendered the issue moot.
When this was discussed in the other newsgroup, it seemed to me the > only barrier was bureaucratic, not technical. There were long replies > of various FCC rules; that if one took at their letter, either Ch 6 > or consumer FM radio receiver manufacturers had been violating > federal law for decades.

I assume that these discussions were for the general case (Channel 6 is vacated after the switch) rather that the specific case of WPVI-DT.

Frankly, I was troubled by the bureaucratic stance; I was hoping > someone would take a consumer or public service stance. That is, > instead of coming up with all sorts of _legal_ reasons why it > couldn't be done, come up with a reason how it _could_ be done.

It can be done, but in the FM band, not outside the FM band. As I've noted before, any television station licensee is free to apply for an FM broadcast license in the FM band.

I hadn't thought about the copyright issue before, but now that you mention it, let me assure you that if a TV station even considered delivering its audio signal via an FM station, the copyright owners would demand a cut. Just consider the demands that copyright owners impose for internet streaming.

Neal McLain

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Neal McLain
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They're considering it. I'll try to contact their P/R person to get the latest.

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Thank you for the explanation which helps. Since the space is in use the issue is moot.

I thought the TV digital transition was to make better use of the bandwidth and make space available for other things, like public safety. That is, the new digital bandwidth would be narrower (use less room) than the old analog bandwidth thanks to the greater efficiency of digital transmission, and, be assigned to a different place on the spectrum. That is, the definition of a TV "channel" would be _entirely_ new. We'd get more 'information' (sharper pictures and better sound) yet use a smaller 'pipe'.

Was the primary purpose of going to digital TV to save bandwidth or to simply give prettier TV pictures?

I presume a TV broadcaster could get an AM license as well for the audio.

The technical siutation--reuse of the same frequency--makes the whole issue _moot_. But if the frequency space _had_ been available, to me the real issue was grandfathering. As technology changes, we allow for many things to be 'grandfathered' in. I simply thought if a station had been audible for at least the last 45 years it ought to continue and not suddenly become a huge legal issue.

For example, in communities that are at a LATA boundary, including state lines, many retain local phone call priviledges across the boundary, even though technically it's inter-LATA and thus a full "long distance" call.

***** Moderator's Note *****

The most important issue, assuming the channel was still available for analog assignments, is that the old analog stations used only 25 Kilohertz deviation on their FM aural carriers, and that meant that they could never match the noise margins of regular FM stations and could never transmit stereo.

Expecting FM broadcast quality audio from a TV audio signal is like trying to record a song by holding a cassette recorder up to a radio. Sooner or later, those who attempt it have to admit that it's not a productive approach.

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Actually, they weren't given a choice. Channels 52 and above are no longer assigned to the broadcast television service.


Reply to
Garrett Wollman

No. The channels are the same width (this is set by international treaty and so can't be modified easily or unilaterally). There are simply fewer channels allocated to television, because the transition means that older tuners, which would have problems with more closely-spaced stations, are no longer relevant for planning purposes.


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