On Sep 4, 9:40*pm, Richard Evans
wrote:
Drewdove wrote:
IMHO too many people laughed off complaints that the digital carriers would
cause interference to first adjacent analogs without realizing these same
adjacent would interfere with the digital carriers rendering HD useless in
certain (many?) situations.

As far as I'm concerned, allowing a signal to be broadcast, at a
frequency that is already allocated to something else, is always going
to be a bad idea (unless it is a system using very directional
antennas). From what I've read in this NG. HD-Radio does just that. It
ends up allowing digital signals to be transmitted on frequencies
already allocated to analogue signals. Whoever thought that would be OK,
obviously either doesn't understand radio, or simply doesn't give a sh*t
about the consequences.

Richard E.

The whole IBOC system was puposely designed to jam the smaller
adjacent-cheenl stations of the dial.

DigitalRadioScams wrote:

The whole IBOC system was puposely designed to jam the smaller
adjacent-cheenl stations of the dial.

So is that why it's so spectrally inefficient?
To use up more bandwidth, hence produce more jamming.

In article ,
Richard Evans wrote:

DigitalRadioScams wrote:

The whole IBOC system was puposely designed to jam the smaller
adjacent-cheenl stations of the dial.

So is that why it's so spectrally inefficient?
To use up more bandwidth, hence produce more jamming.

The idea was to ultimately retire analog FM entirely, thus enabling
iBiquity to capture a royalty on every bit of material on the FM band.
iBiquity understated the amount of IBOC signal necessary to achieve
"equivalent" coverage with the stations' FM signals so that it could get
its foot in the door.

When it became apparent that -20db was inadequate (even though there was
still major interference with analog signals), they lobbied for -10db.
That was an "oops" of an order of magnitude. They got -14db instead, but
the deleterious effects on analog FM at that level remains to be seen,
since most stations have yet to take advantage of it.

--
John Higdon
+1 408 ANdrews 6-4400
AT&T-Free At Last

On 9/5/10 7:40 PM, John Higdon wrote:
iBiquity understated the amount of IBOC signal necessary to achieve
"equivalent" coverage with the stations' FM signals so that it could get
its foot in the door.

I think we have seem the same thing for DAB and DRM. The low powers are
just sales talk.

gr, hwh

hwh wrote:


I think we have seem the same thing for DAB and DRM. The low powers are
just sales talk.

Lower power would be fine, if DAB had better error correction.

Although there is one situation where low power DAB works well, that is
in the middle of an SFN with signals coming in from several different
directions. This isn't much use however in the outer areas of a local
multiplex.