December 5, 2007
Digital AM Nighttime Interference Claim Filed
Radio World reports that a Rochester, NY, radio station has filed a complaint with the FCC over nighttime digital AM interference: Radio World reports this is thought to be the first such complaint. The complaintant, Radio Livingston, runs WYSL, while CBS Radio runs the station that's being complained about. WYSL uses just 500 watts at night (20 kilowatts daytime) while CBS uses 50 kW 24 hours a day. The complaint was filed in October. It's worth noting, as this article does, that WYSL's owner believes in-band, on-channel (IBOC) digital encoding for AM is "bad for AMs that remain analog."
December 3, 2007
HD Radio's AM Troubles: No Real Solution Ahead
Radio World offers a balanced look at the problems with early full-time AM radio deployment of HD Radio, but it's clear that the solution may be ugly: It's been known for some time that iBiquity's technology for digital AM radio was a compromise the outcome of which was unclear. Since the FCC approved 24-hour-a-day digital AM broadcasting--up from daylight hours only--more knowledge has been gained about precisely how much interference is caused to adjacent and distant stations.
Radio World doesn't conclude digital AM is busted, because, they note, "not enough [AM] stations have been transmitting HD Radio at night to provide a realistic evaluation of the consequences."
However, there's no question there's trouble. The consequence of the FCC intervening where interference is present and requiring stations to back off, or of iBiquity being forced to go back to the drawing board, is digital AM/FM as a whole would suffer a huge blow.
Without AM stations being able to deliver a higher-quality digital signal reliably across their coverage area at night, they're unlike to promote HD Radio much, and their listeners are unlikely to upgrade over time. It's serious enough that, Radio World writes, "Owners like Clear Channel and CBS reportedly are having to choose which AM HD stations to leave on at night and which ones they’ll turn off due to interference inflicted on more important co-owned stations."
If iBiquity is forced by broadcasters or the FCC--the latter being unlikely given the commission's full-on approval--to change AM encoding that would likely mean that all HD Radios sold up until that point would be unable to receive future digital AM transmissions. Radio World notes, correctly, that that wouldn't be a problem if updates could be performed via software. It's possible that the chips deployed so far have that ability and could be flexible enough--although only a few radios have an easy way to handle upgrades. (Some can be upgraded by dealers and manufacturers, I've been told).
But this is not good news.
I've been concerned from the beginning of my coverage of digital AM/FM about the paucity of AM stations broadcasting in HD Radio format. I was told that the lack of 24-hour broadcasting ability was the big reason. But I was also told about the compromises that led to the AM specification being adopted.
The more widely spread the knowledge among consumers (and retailers) that digital AM is up in the air, the less likely receivers will be sold.
October 24, 2007
Pushback on HD Radio in AM: Citadel Turns off Nighttime AM
Criticisms of problems in using HD Radio encodings for AM stations date back to the earliest days of the technology: The FCC approved nighttime broadcasting of HD Radio over AM a few months ago, but there are still relatively few AM stations using HD Radio, and thus problems are only starting to emerge. At night, the so-called D region of the ionosphere changes character and reflects rather than dissipates signals in the AM radio range. AM radio signals already travel thousands of miles further than intended at night, and both hobbyists (DXers) who enjoy tuning in far-off stations, and regular radio listeners could be affected by digital signal skipping.
I've had a mixed opinion on this front, expecting that if there were real problems, then the FCC wouldn't approve nighttime broadcasts, that broadcasters wouldn't deploy such signals, and that lawsuits would be filed. I don't mean to be naive about the money involved, because broadcasters are equally concerned about interference that prevents their own stations from being heard.
Radio World reports that Citadel Broadcasting, which has HD Radio enabled on 16 of its 66 AM stations, decided to turn off the 10 stations that were broadcasting digital signals at night due to reports of interference. The problem occurs when listeners hear "hiss" and stations on nearby channels hear noise.
There have been rumors all along that AM digital encoding is inadequate and will need to be entirely rethought--that is, the underlying encoding replaced with a superior one. This would require replacement of all the HD Radio sets on the market, except those that have upgradability through various means (USB ports and discs that can upgrade firmware) almost certainly, as any solution would likely require new silicon.
We'll see what happens here. It's possible that in production HD Radio won't be able to work at night; that's always been a concern, and now they have to tweak parameters while still maintaining compatibility.
March 15, 2007
Nighttime AM, FM Multicasting on FCC Agenda?
On March 22, the FCC could move ahead to authorize nighttime AM broadcasting, and fully authorize FM multicasting: There are many heated opinions about the quality and nature of iBiquity's in-band, on-channel AM encoding and broadcasting technology. Right now, AM stations can only broadcast during daylight hours, which severely limits HD Radio's inroads into AM stations. It's fair to say that AM stations have a vast amount to gain by going digital because of the potential quality of signal improvement, loss of tunnel fadeout, and elimination of other problems. Please note: I have not heard broadcast AM HD Radio! I was unable to tune in the one station in my market because it's far too distant from Seattle during my testing last November of five HD Radio receivers.
The FCC could approve nighttime broadcasts, and I suspect there will be loud wailing and gnashing of teeth that follows, and perhaps lawsuits. We'll see.
The other issue that might be considered is full authorization for FM multicasting. While the idea of many digital channels on an FM station is part of the marketing pitch for HD Radio, each station must apply to the FCC at the moment to multicast. Removing that obligation reduces cost and friction.
February 12, 2007
Regional Stations Add HD Radio
The Seattle Times reports on smaller stations adding digital signals: The Washington State round-up notes that KRKO in burgeoning Snohomish County north of Seattle--and increasingly populous suburb/exurb region--will add HD Radio to its AM offering. This is one of the few stations in the country to opt for it. The timing is coincident with an upgrade to its analog signal from 5,000 to 50,000 watts. AM radio could see a big boost from HD Radio, with signals not just being much higher fidelity, but with the typical woo-woo sounds of AM and the loss in tunnels and under bridges disappearing as problems. AM has a harder sell on the costs, though, since multiple channels aren't possible.
March 1, 2006
AM Stations' Distant Listeners Hear Static
The Wall Street Journal highlights a side-effect of digital AM using HD Radio: More distant listeners who used to get a clear analog AM signal now experience fuzz and his from adjacent broadcasters who have added HD Radio. This doesn't bother the FCC because the interference isn't heard in core areas, this article notes. But it does reduce listenership.
This article also notes that an anti-trust lawsuit has been filed by Leonard Kahn against iBiquity and Clear Channel because the only FCC-approved digital AM/FM technology is controlled by iBiquity which has a set of investors that include major radio firms like Clear Channel.