Digital Radio taking over the AM band?
Update on the IBOC
The mediumwave (AM) band in the
United States is gradually turning digital. In October
2002 iBiquity's digital IBOC technology was approved
for AM and FM broadcasting in the United States.
Currently 19 U.S. AM stations are listed using IBOC
technology to broadcast simultaneously in both the
analog and digital modes - however, only half a
dozen stations have been observed experimenting
IBOC stands for in-band on-channel
technology, which enables digital broadcasting in
the AM and FM bands while analog signals continue
to be transmitted at the same time.
present IBOC system is referred to as a hybrid,
because it is neither totally analog nor fully digital.
During hybrid operation, existing receivers still
continue to receive the analog signal. New digital
receivers being developed are expected to incorporate
both modes of reception, where receiver will automatically
switch to the analog signal if the digital signal
cannot be decoded or is lost by the receiver.
Enhanced sound quality and the
potential for new wireless data services are the
most important improvements cited by proponents
of the IBOC technology. IBOC digital radio is expected
to provide near CD quality reception for stations
operating in the FM broadcast band. For AM stations,
IBOC digital radio is expected to provide reception
approximately equal to today's analog FM reception.
Officially, minimal impact is anticipated on reception
of existing service. DXers however are worried that
digital broadcasting will gradually ruin AM DXing
- or at least the way AM DXing has been practised
About 130 stations have been
licensed by iBiquity to use the technology. As of
March 20, 2003, stations haven't needed a permission
from the Federal Communications Commission (FCC),
they only need to inform the FCC within 10 days
of having begun experimenting with IBOC.
According to information received
and published by the FCC, the following stations
were using the IBOC hybrid technology at the time
of writing (April 22, 2003):
||station and location
||WJNA Royal Palm
||KCBS San Francisco
||KXNT North Las
||WWJ Detroit MI
||WBZ Boston MA
||KNX Los Angeles
||WTWZ Clinton MS
North Miami FL
New Brunswick NJ
Pompano Beach FL
However, DXer Charles Hutton
has pointed out to DXing.info that none of the above
stations are actually on the air using IBOC. Instead,
according to information collected by him, only
the following stations are known to have experimented
with IBOC more than just once:
||station and location
Cincinnati OH - did nightime tests several months
ago as part of a special study that is now over
New York NY - the only daily user of IBOC
Atlanta GA - has tested IBOC once
North Las Vegas NV - only uses IBOC for tests
during the NAB conventions in Las Vegas
Taylor MI - was a frequent user in the past
Cincinnati OH - is testing but has not yet started
using IBOC daily
DXing.info also had a Q&A
session with Laura Taylor, public relations official
at iBiquity, to find out more about the current
status of IBOC broadcasting. Here's what the developer
of the new technology has to say.
there any difference between AM and FM stations
as to what extent IBOC has been adopted?
- HD Radio technology is being adopted in small,
mid-size and large markets across the US. Stations
in these markets that are licensing are primarily
FM, but we also have strong support from AM stations.
I believe right now the numbers break down into
70% FM and 30% AM.
you provide a list of the
AM stations that will shortly begin using IBOC?
- The process of
licensing from iBiquity is at the very beginning
of a larger process for turning the station on the
air. Factors contributing to going live include
FCC licensing through equipment ordering. Therefore,
iBiquity does not track when stations go on live
with an HD Radio system.
are your first impressions of these test broadcasts?
- We have had very
positive feedback from the broadcast community and
the FCC. With full confidence in the viability of
our product, the FCC approve our IBOC-based HD Radio
technology for use as the standard for delivering
digital in the US. We expect that the upgraded sound
quality and services will be a great benefit to
the broadcasters as we move forward with rolling
out this technology and as it reaches the consumer
A presentation of a Kenwood
IBOC home receiver which become available
is the status with consumer receivers - how widely
are they available and what is the consumer price?
has HD Radio Ready product on the shelf right now,
with a black box solution to ship in the summer
of this year. By winter 2003, we expect product
widely available on the retail shelves. Other partners
committed to product this year are Harman Kardon
and Yamaha. To check on specific dates, I would
defer to the manufacturers to give you the answer.
is your comment on criticism that IBOC is causing
interference to analog stations on the same and
even on adjacent
- HD Radio
technology is one of the most thoroughly tested
broadcast technologies ever developed. We have gone
through extensive testing over a four year time
frame and have turned those results over to 3rd
parties and the US govt (FCC) for review. The FCC
has determined that our technology is acceptable
for use and does not significantly impact adjacent
stations through interference.
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(published on April
22, 2003, updated on May 11, 2003)