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Tuesday, August 16, 2005



Digital Radio:
When More (bandwidth) is Less (choice)

Another way to think of this is to compare an analog photograph with a digital fax ... the fax picture is a series of dots that are "on" (black) or "off" (white space).What is "Digital Audio Broadcasting"?
Digital is a new way of using electricity to store music, voice, and information. Digital information is "binary" (either on or off, one or a zero) using pits (or no pits) to code the music on compact discs or bursts of energy for computer communication, instead of smoothly varied signals taken from vinyl records, for example.
If you look very very closely, you will see that a facsimile printout is a digital "binary" (on or off) format of information. Look closely and you will see a series of squares that are either white (off) or black (on). There is no grey in-between, its either black or white. Contrast that digital storage and transmission with a photograph. Look very closely at the photo, on the other hand, and you will see greys and colors, in nearly infinite shades.
Currently radio stations transmit in analog, but take the music from a digital storage format.
Please don't confuse the digital display of your analog tuner's controller with DAB.Just as the fax machine screeches into the phone line to transmit those blocks of binary information that makes up a picture, so will "Digital Audio Broadcasting" make sounds very like a fax machine into your radio reciever!
Several years ago most of the rest of the nations of planet Earth created a third separate broadcast band to create Digital Audio Broadcasting (DAB) radio stations.
Large american broadcasters represented by the National Association of Broadcasters (NAB) wanted to do the same in the United States. Unfortunately the US military wanted to continue using those bands of frequencies to transmit and recieve information for testing of military machinery. Modern technology makes this utterly unecessary, since now there are much higher frequencies available with much greater security with the current state-of-the-art available to the military. The retention of the 1400mHz "L-Band" by the US Military is especially ironic since now Europe and Canada are filling those frequencies with broadcasts thus making them largely useless to the US Military. Additionally, regular citizens can now easily build and modify equipment to transmit and recieve in the "L-Band" and thus these frequencies are not secure! The military should go ahead and move on to the higher more secure frequencies!
There's no point in testing your missile only to have Elvis on the "L-Band" take over control of it!
Example: from Richmond, Va., WHRV89.5FM and WAUQ89.7FM are "first adjacent" stations, that is they are on each other's first frequency channel adjacent to each other. Currently a good receiver can separate these two weak and distant stations right next to each other on the richmond radio dial. When they double in bandwidth, we will hear neither station ever again, nor will the rural people in between of Jamestown or Tidewater, Va. At least if these were NEW stations there would be new programming sources ... but instead we just lose two sources. They are not replaced with new programming outlets. But in 1992, the military would not yield and so the NAB thought they would instead place these DAB signals In the AM and FM Broadcast Band, centered On the existing radio station Channels (hence the acronym IBOC-DAB)
This is where this particular way of employing Digital became a threat to your favorite radio station. The NAB proposed to place the DAB "audio fax machines" just immediately (in radio-speak, "adjacent") above and below each analog radio station. The idea is that they will transmit both in analog and in digital for a few years, and eventually turn off the analog broadcast transmitter and end up with a fully pure DAB band that will completely replace the existing current analog AM and FM Broadcast bands.
Sounds great, eh? The problem is that a side-effect of doubling the width of a radio station is that if your favorite radio station happens to be a weak little independent college, religious or community mom&pop radio station right next to a high-powered blow-torch of a radio on the broadcast dial ... you very likely will not be able to recieve your favorite station again.
In other words, your favorite station's signal is jammed by the big stations digital signal!
Some will tell you that FM technology will reject the IBOC noise, but when WJFK ran an actual test IBOC signal, we went up to Northern Virginia to test their proposition that it would not affect our radios.
We made an actual recording of the IBOC signal jamming the next station down on the dial!! Then we testified to Congress regarding IBOC and gave Congress the actual sounds of test IBOC stations destroying another station's signal as well as more discussion of the misleading nature of the NAB testimony.
In this image here to the right of this text you can see a rough graphic representation of the proposed IBOC-DAB signal distribution and the graphic shows how this would destroy your access to recieve a neigboring signal if you are living in-between the two stations.
The current "In-Band On-Channel, Digital Audio Broadcasting" (IBOC-DAB) proposal would force mandatory "sunsetting" or prohibition of existing affordable analog FM stations, making them broadcast in digital.
Adding insult to injury, it would allow big stations to more than double their bandwidth. This would reduce the "buffer space" between many stations to a negative number ... station's signals would overlap and your receiver would "hear" both simultaneously ... utter gibberish would result. (See examples)
To see for yourself how this works, tune to a nearby powerful FM station and click once in either direction, notice that the signal is still there. Click twice, it vanishes. Under the proposed rules, two clicks in either direction would be taken and the powerful station would literally jam other signals nearby on the dial but geographically distant or weak.
The effect is like the Nazi radio giveaway because it destroys by law our ability to receive weaker or more distant signals but does not allow local competition to replace that loss with new programming sources. All Germans, whether they liked it or not, heard Hitler 's latest speech and no counterpoint.
Technology Investor magazine affirms the economic viability of subscription Satellite radio services citing research that shows that "30% of CD sales are in music genres rarely heard on the radio dial." What is especially galling is that the NAB, SONY etc. argue that they need IBOC-DAB in order to "compete" with satellite and the Internet ... sidestepping the fact that it is not the digital sound that drives interest in expensive and inferior technology such as Satellite and Internet audio ... it is the variety that Sony even admits in their official statements are not available on the FM dial.
Under IBOC-DAB, spreadsheet driven robots playing repetitive programming, blaring ads, and irritating call-in schemes broadcast at 40,000 watts would dominate even more mercilessly than they do now.
Commercial radio content has little to do with Nazism, unless the latest bleating teen idol brings you to a murderous rage. But IBOC-DAB would knock out what many (about 20%) listeners prefer; the smaller noncommercial college, community, and religious stations.

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