On Wed, 23 Jan 2008 14:52:57 -0800, tom k in L.A. wrote:

Please enlighten me: Why is IBOC so Evil?

The primary complaint is that the IBOC digital signal is transmitted in
two channels either side of the station using it, causing massive
interference.

For example, if a station on 1510kHz runs IBOC, the digital signals are
transmitted in 1495-1505kHz (interfering with stations on 1490 and 1500)
and from 1515-1525kHz. (interfering with 1520 and 1530kHz)

(on FM, only one frequency on each side is interfered with, and in many
cases those frequencies were already useless due to interference problems
involving the station's *analog* signal. It does make things hard on
FM DXers though.)

Other complaints:

- Poor coverage in the current "hybrid mode", where analog simulcasts must
be accomodated.

- Self-interference: if the station isn't balanced properly or the
receiver has an unusually wide IF bandwidth, the IBOC digital signal can
interfere with the station's own analog signal.

- We could have had something better. A system called "Eureka-147" is
seeing success in Britain and at least in technical terms across Europe.
This Eureka system would have offered improved fidelity over IBOC, more
subchannels, and no interference issues.