I usually listen to Portland's AM stations. My understanding is that the FM stations in the area--at least the most powerful ones--broadcast in stereo.
Can someone give me the skinny about this?
Posted on October 5, 2011 - 10:06 PM
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FM stations in stereo?
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http://pdxradio.com/FM_AM_Owners.html
That page here on the board lists the stations and their stereo and digital radio status.
Digital FM is stereo, but requires a new radio capable of receiving the digital broadcasts.
Ordinary FM is stereo on nearly all stations. KXL FM is a talk station, and is currently airing a mono broadcast.
Honestly, why not just grab hold of a FM radio and check them out?
Posted on October 5, 2011 - 10:29 PM # -
I remember KBOO was the last mono FM, changing in 1986 or 1987.
Posted on October 5, 2011 - 10:31 PM # -
Isn't KEX running in mono on FM, too?
(I'd check but I'm sitting in Nebraska right now. Hi, Deane! ;o)
Posted on October 5, 2011 - 10:36 PM # -
Multiplex stereo began in Portland on KPFM 97.1MHz December 16, 1961. Although stereophonic sound had been heard in Portland since February 8, 1953 when KPFM and sister KPAM 1410KHz together presented the first binaural demonstration in 3-D sound as it was called. Regular broadcasts continued on those stations with KOIN AM/FM & KPOJ AM/FM picking up the idea in the late 1950's as well.
STEREO CONVERSION DATES OF AREA FM'S
1. KPFM 97.1 - December 16, 1961
2. KGMG 95.5 - March 17, 1962
3. KOIN-FM 101.1 - May 7, 1967
4. KPOK 98.5 - August 15, 1968
5. KJIB 99.5 - September 21, 1968*
6. KINK 101.9 - December 25, 1968*
7. KSLM-FM 105.1 - July 3, 1970*
8. KOAP-FM 91.5 - March 3, 1972
9. KQIV 106.7 - September 15, 1972*
10. KGON 92.3 - February 1, 1974
11. KQFM 100.3 - March ?, 1975
12. KMJK 106.7 - August 1, 1977*
13. KPDQ 93.7 - June 1, 1979
14. KBPS-FM 89.9 - August 1, 1983*
15. KMHD 89.1 - between January 11 & 14, 1984*
16. KKCW 103.3 - February 24, 1984*
17. KBOO 90.7 - August ?, 1986.* = Denotes station initially began operation in stereo.
Posted on October 5, 2011 - 10:36 PM # -
An interesting fact that was pointed out on this board a few years ago is that in the US virtually all FM stations (except LPFMs) have the capability to broadcast in stereo. One reason for this is that some 40 years ago, an engineer by the name of Bob Orban created an "appliance" called the Optimod that combines the functions of the AGC/compressor/peak limiter, the pre-emphasis circuit, and the stereo encoder (including the required lowpass filter to prevent high frequency sounds from interfering with the stereo pilot tone). The left and right channel audio went into this plug-and-play box and a composite signal, ready to be sent to the transmitter came out. The Optimod became so popular that many other broadcast equipment manufacturers rushed to design their own versions. The other reason for this is that in today's corporate ownership environment, broadcasters want the ability to change over to stereo operation without a hassle, should the station change formats to one requiring stereo. Thus virtually everyone puts an Optimod (or its equivalent) in the airchain, and they literally just flip a switch on the Optimod if they want to broadcast in mono.
LPFMs are a special case because there are commercially available transmitters designed for mono operation. These transmitters include the audio AGC/compressor/peak limiter, but there is no stereo encoder circuit. They are designed to be simple so that people with minimal RF/broadcast skills can maintain the station.
Posted on October 5, 2011 - 11:35 PM # -
It would appear that KPDQ-FM has been mono, since reducing class, in order to make room for KRYP, on 93.1.
Posted on October 6, 2011 - 01:25 AM # -
A quick scan from my location (Hillsboro) reveals only four FM stations that are not received in stereo. This includes many out of town stations, translators, low power stations, as well as high power Portland stations.
93.9.....KPDQ
101.1...KXL
102.3...KEX translator
102.9...KQSO (low power)Posted on October 6, 2011 - 11:32 AM # -
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Yes!
Posted on October 7, 2011 - 08:29 PM # -
"It would appear that KPDQ-FM has been mono, since reducing class, in order to make room for KRYP, on 93.1."
Please explain how broadcasting in mono "make(s) room" for another station?
A lack of spectral presence at ±(23 - 53 kHz) from center frequency is not space someone else can use.Posted on October 13, 2011 - 01:08 PM # -
As I understand it, during the "great shuffle" to move-in KAST to Portland (became 93.1) many stations changed frequency and or power to make the the scheme work. KPDQ ended up reducing power. As a result, their ability to supply their translators with a noise free signal suffered. Switching to mono fixed the noise problem.
Posted on October 13, 2011 - 01:25 PM # -
I love the English language. KPDQ changed frequency to make room for KRYP and needed to reduce class. I heard at the time that switching to mono, gave them enough signal to feed their translators, since they had to decrease power.
Posted on October 13, 2011 - 01:26 PM # -
Back when I used to work for KPDQ. 76-93 ish. When we went to talk programs at 6 a.m. until about midnight. We turned off the sterio pilot. It was not just for the translators. But the over the air signel went further in mono. This is not new.
Posted on October 13, 2011 - 01:34 PM # -
Back when I used to work for KPDQ. 76-93 ish. When we went to talk programs at 6 a.m. until about midnight. We turned off the sterio pilot. It was not just for the translators. But the over the air signel went further in mono. This is not new.
There was a regulation (long rescinded) that required FM stations to turn off the stereo pilot when broadcasting x minutes of monophonic programming. This was such a pain to do (DJ's often forgot to turn it back on) that during the news many stations mixed music in the background to make it stereo.
As a kid I remember hearing newscasts on FM stations that had rock instrumentals in the background. One station always played Edgar Winter's "Frankenstein" so it became "The News Song" to me.
Posted on October 13, 2011 - 01:54 PM # -
I recall when television stations would turn off the color subcarrier (including the colorburst) for black-and-white programs. This practice continued at some stations until the early 1990s.
Posted on October 13, 2011 - 02:42 PM # -
I recall when television stations would turn off the color subcarrier (including the colorburst) for black-and-white programs.
What did they do for commercials? Was it automated?
Posted on October 13, 2011 - 05:07 PM # -
...believe it WASN'T; they had human engineers do it all...
Posted on October 13, 2011 - 08:52 PM # -
Being a radio guy all my life since the early 70's with cart machines we had it pretty easy...I heard of "horror" stories of TV stop sets of cueing up 2 inch tape video tape machines with dead-roll timing that had to sink up...start of new thread...60's/70's TV stopset tech talk...
Posted on October 13, 2011 - 10:10 PM # -
...believe it WASN'T; they had human engineers do it all...
I wonder if they had people calling up the station when they forgot to flip the switch, just like we did for years in the early days of HDTV. In the 1960's a color television cost the equivalent of an HDTV set in the early 2000's so that must have sucked to watch Bonanza in black and white!
Posted on October 14, 2011 - 03:31 PM # -
Back in the mid 70s, Y-100 in Miami would switch to mono on big beach afternoons, so the station would sound louder and better on portable radios being used at the beach.
Posted on October 14, 2011 - 03:44 PM # -
I have noticed that on almost all the tapes I have heard that were recorded off FM stereo transmissions during the 60s and 70s, they almost always announce the station as being transmitted in stereo, usually in the hourly idents (e.g. "Today's music every day, on stereo 92 in Omaha, WOW-FM" from one tape I have that a neighbour recorded whilst living in Nebraska in 1971.)
Were stations required by the FCC to announce that, or did they just do it for marketing?
Posted on October 14, 2011 - 08:17 PM # -
I'm going to go with "marketing" on that one. They were still trying to catch AM and the gimmick sure didn't hurt! We bought our 25 inch Magnavox Console Color Stereo Theater for $795 in 1967. That would probably be quite a bit in today's dollars but electronics have always been like that.
Posted on October 14, 2011 - 09:30 PM # -
As I understand it, the color/monochrome switching only applied to programs originating at the television station. When stations switched to network programming (at least in the early days of color), the video from the network feed was sent directly to the transmitter, sync, colorburst, and all. I think that even in the mid 1980s, I recall that the video on some stations (such as WPSX, Channel 3, Clearfield, PA) would "glitch" during transitions from local programming to network programs.
I did read an account that in the early days of color television, the FCC started to crack down on network affiliates who did not have the proper equipment to monitor the color transmissions that they received from the networks. A few stations chose to install a 3.58 MHz trap in line with the video to remove the color signal, rather than to buy the proper monitoring equipment.
Posted on October 17, 2011 - 12:40 AM # -
Someone (here I think) was talking about the shoddiest televisions stations they knew of. One was a small affiliate in Washington that refused to broadcast in color until the mid-70's. The owner simply didn't want to spend the money on whatever new equipment would be needed for that luxury.
The NBC affiliate in Terre Haute, IN was famous for refusing to broadcast in HD for years even though they had their ATSC transmitter up and running. They broadcasted NBC's SD feed in 480i instead. Apparently they didn't want to spend the money on an HD MPEG encoder to convert the network feed to ATSC (a very significant expense ten years ago). What made it extra funny was that their local newscast set had huge widescreen monitors everywhere.
Posted on October 17, 2011 - 10:42 AM # -
Isn't high definition an option and doesn't KNMT use SD to provide more channels?
Posted on October 17, 2011 - 11:56 AM # -
Yes, there is no regulation that say television stations must broadcast in high definition. Nor was there any regulation that said they must broadcast in color. It's one of those "give me a break" things.
MPEG encoders are a major expense and ten years ago they were a very major expense. KOIN's first encoder was their second largest expense in their ATSC conversion right behind the new transmitter. I can see how a small station might put off spending a couple hundred thousand dollars for a while. They're much cheaper (and much better) now.
Posted on October 17, 2011 - 01:50 PM # -
Many DTV stations do indeed show their multicasts in what amounts to an analog format. KRCW, for example, carries NBC-Universal Sports, which often letterboxes events originally produced in full widescreen (Bicycle racing, like the Tour of Spain, is a good example). Analog-format multicasts take up less room than full HD channels would, as I understand it. Comcast does not carry a single multicast service in full HD. I don't know how many are actually downconverted, but it's worth noting that Comcast does not carry all of the multicasts available in the Portland/Vancouver/Salem area..for example, no TBN multicasts, and no KPXG/Ion multis, eiether...Best, M.
Posted on October 17, 2011 - 05:19 PM # -
These "analog" format stations like Universal Sports could all broadcast in SD 16:9 widescreen. It's right in the ATSC standard. It's effectively the same as a DVD which is a familiar format for most people. Since it's anamorphic, it does not take up any more bandwidth than the 4:3 format. All digital broadcast equipment made in the past decade can handle it.
For some reason the subchannel networks are all sticking to the sixty year old 4:3 VHS videotape format.
Posted on October 18, 2011 - 08:57 AM # -
VHS came out in the mid 1970s, which makes it significantly less than sixty years old. Unless they are using the similar "M" system, as far as I know professional applications like TV sub/channels usually tend to use some variant of U-Matic or Beta, or these days probably even DV. Even in SP mode, VHS doesn't have the bandwidth necessary for broadcast-quality video.
Posted on October 18, 2011 - 11:54 AM # -
The 4:3 aspect ratio standard actually dates back to the early development of 35mm film, circa 1892....But, this thread has really veered off topic!
Posted on October 18, 2011 - 12:17 PM # -
I think 35mm actually has a marginally narrower ratio than 4*3, accounting for the analogue audio/timecode tracks, doesn't it? In this example (http://upload.wikimedia.org/wikipedia/commons/c/cc/Anamorphic-digital_sound.jpg) the frames look almost square.
(But I guess with an anamorphic print, that's kind of a moot point...)
Posted on October 18, 2011 - 01:20 PM # -
The Wikipedia article on aspect ratios explained that the exact aspect ratio of a 35mm print with sound is 1.37:1 (instead of 1.333:1). This doesn't make sense to me, as I would have expected for the picture to become skinnier (and thus, the numerator smaller) with the addition of the soundtrack. Perhaps, a slight vertical shrinking of the picture accompanied the introduction of the soundtrack.
Posted on October 18, 2011 - 01:44 PM # -
The 35mm standards have changed over time.
"Silent films were shot at a 1.33 aspect ratio, with each frame using all of the negative space between the two rows of film perforations for a length of 4 perfs.[1][2] The frame line between the silent film frames was very thin. When sound films were introduced in the late 1920s, the soundtrack was placed down a row along the inside of one of the lines of perforations, cutting into the 1.33 image.[1][2] This made the image area "taller", usually around 1.19, which was slightly disorienting to audiences used to the 1.33 frame and also presented problems for exhibitors with fixed-size screens and stationary projectors."
http://en.wikipedia.org/wiki/Academy_ratio
"In the conventional motion picture format, frames are four perforations tall, with an aspect ratio of about 1.37:1, 22 mm by 16 mm (0.866 in × 0.630 in). This is a derivation of the aspect ratio and frame size designated by Thomas Edison (24.89 mm by 18.67 mm or 0.980 in by 0.735 in) at the dawn of motion pictures, which was an aspect ratio of 1.33:1.[30] The first sound features were released in 1926–27, and while Warner Bros. was using synchronized phonograph discs (sound-on-disc), Fox placed the soundtrack in an optical record directly on the film (sound-on-film) on a strip between the sprocket holes and the image frame.[31] "Sound-on-film" was soon adopted by the other Hollywood studios, resulting in an almost square image ratio of 0.860 in by 0.820 in.[32]
By 1929, most movie studios had revamped this format using their own house aperture plate size to try to recreate the older screen ratio of 1.33:1. Furthermore, every theater chain had their own house aperture plate size in which the picture was projected. These sizes often did not match up even between theaters and studios owned by the same company, and therefore, uneven projection practices occurred.[32]
In November 1929, the Society of Motion Pictures Engineers set a standard aperture ratio of 0.800 in by 0.600 in. Known as the "1930 standard,""http://en.wikipedia.org/wiki/35_mm_film#Common_formats
"This list of film formats catalogues formats developed for shooting or viewing motion pictures, ranging from the Chronophotographe format from 1888, to mid-20th century formats such as the 1953 CinemaScope format, to more recent formats such as the 1992 IMAX HD format. To be included in this list, the formats must all have been used in the field or for test shooting, and they must all use photochemical images that are formed or projected on a film base, a transparent substrate which supports the photosensitive emulsion."
http://en.wikipedia.org/wiki/List_of_film_formats#Film_formats
"1.15
Sometimes referred to as the Movietone ratio, this ratio was used briefly during the transitional period when the film industry was converting to sound, from 1926-32 approx. It is produced by superimposing an optical soundtrack over a full-gate 1.33 aperture in printing, resulting in an almost square image. Films shot in this ratio are often projected or transferred to video incorrectly using a 1.37 mask. Examples of films shot in the Movietone ratio include Sunrise, M and Hallelujah!.[4]
1.33 (4:3)
35 mm original silent film ratio, today commonly known in TV and video as 4:3. Also standard ratio for MPEG-2 video compression. This format is still used in many personal video cameras today and has influenced the selection or design of other aspect ratios. It is the standard 16 mm and Super 35mm ratio.
1.37
35 mm full-screen sound film image, nearly universal in movies between 1932 and 1953. Officially adopted as the Academy ratio in 1932 by AMPAS. Rarely used in theatrical context nowadays, but occasionally used for other context."http://en.wikipedia.org/wiki/Aspect_ratio_(image)#Previous_and_currently_used_aspect_ratios
Posted on October 18, 2011 - 01:46 PM # -
Or to summarize quickly: movies are generally either 1.85 (by covering one fourth of the 35mm frame in projection or only exposing three fourths of it) or 2.35 (by printing half of the 35mm frame, or by using an anamorphic lens to squeeze the wide image into 35mm frame).
Almost everything is shot 16:9 (1.78, close enough to 1.85) in television these days. In the U.K. all television production has been 16:9 for years. Any station that wants to broadcast widescreen movies that were panned and scanned in 4:3 might as well be asking the viewer to watch a VHS videotape instead of a DVD.
I think the problem is that broadcast distribution for all widescreen movies in the U.S. is in an HD format so they'd have to be converted for a lower resolution widescreen SD broadcast.
Posted on October 19, 2011 - 03:37 PM # -
Could this film talk be moved to its own thread?
Posted on October 19, 2011 - 10:02 PM # -
No, it cannot!
Posted on October 21, 2011 - 03:43 PM # -
I am enjoying it.
Posted on October 21, 2011 - 04:43 PM # -
It's not that I don't enjoy it, but this thread is supposed to be about something totally different.
Posted on October 22, 2011 - 09:01 PM # -
That's why it's called a thread!
Posted on October 22, 2011 - 09:48 PM # -
Yeah, that tends to happen. We don't have threaded discussion here, just single threads. Of course, if we did have real threaded discussion, the interface would be more complex and so there you go.
One way I've seen work well is to just do:
So, as you were all saying...
"Stereo" as a marketing term was potent. Lots of people took their time transitioning to Stereo radios. Table radios, clock radios, car radios and other simple, basic radios were more mono than not. Early stereo sets were kind of crappy sometimes, almost as if the cost had to be exactly the same, but just add "Stereo".
As a kid, I would prefer the mono broadcasts, being used to AM radio, and not having AM Stereo gear early on, mono seemed just fine. It was clearer out on the fringes where I lived too. Home receivers did a pretty fine job of stereo, but a lot of portables really didn't. They were much more fiddly than mono receivers were.
...and so on.
Posted on October 22, 2011 - 10:03 PM # -
Multiplex was never a great system, more susceptible to multipath and just plain noisier but it was compatible with monaural and in 1961, that's about all they could do. Fortunately, they've made improvements in transmitting and receiving equipment and a new method of transmission is being considered, that should make up for a lot of the quality difference between mono and stereo!
Posted on October 23, 2011 - 12:08 AM # -
"...A
new method of transmission is being considered, that should make up for a lot of the quality difference between mono and stereo!"A new *analogue* method, or do you mean the Ibiquity System?
Posted on October 23, 2011 - 12:30 AM # -
Gotta be.
Posted on October 23, 2011 - 01:03 AM # -
analog. The only problem is that it isn't completely compatible with all radios built before 1973.
Posted on October 23, 2011 - 03:47 AM # -
Do tell
Posted on October 23, 2011 - 09:48 AM # -
Yes, please! I am all ears!
<----Posted on October 23, 2011 - 10:21 AM # -
The Wikipaedia article on FM broadcasting mentions nothing except the current system. I'm thinking phase modulation multiplexing. (Don't know why, it just came into my mind.) Unless the proposal is to transmit two discrete mono channels on two seperate frequencies.
Maybe a revival of the old Dorren quad system? Of course, if that came to pass it would also have to include a revival of KQ4!
Posted on October 23, 2011 - 11:20 AM # -
You guys are dreaming. Nothing is going to change any time soon. The L+R baseband and the L-R sideband and the pilot will remain. The addition of HD digital subcarriers was a major change and has occurred in the last decade, and changes of large proportion at the FCC don't come around that often and when they do, there is such a long process involved it can take up to 15 years from conception to implementation.
"phase modulation multiplexing."
A lot of modern FM exciters use phase modulation to achieve frequency modulation.
AM transmitters started using phase modulation techniques back in the late 70's (see RCA Ampliphase).Posted on October 23, 2011 - 11:27 AM # -
Here's the original article from RW Online: http://www.rwonline.com/article/a-method-to-improve-conventional-fm-stereo/4000 Later articles show promise that the concept will be adopted.
Posted on October 23, 2011 - 12:26 PM #
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