[opendtv] Re: An HD Radio stereo AM/FM tuner at last

  • From: "Manfredi, Albert E" <albert.e.manfredi@xxxxxxxxxx>
  • To: <opendtv@xxxxxxxxxxxxx>
  • Date: Thu, 12 Oct 2006 16:04:46 -0400

Steve Wilson wrote:

> In HD radio, they are reusing the same frequencies so you need
> the same kind of antenna....is this correct?


It is in fact conceptually very similar to ATSC or DVB-T, in that the
same basic slice of RF spectrum is used for the analog and the digital
signals of the radio or DTT service, and also in that (so far anyway)
the digital signal is being sent at a considerably lower power level
than the analog.

The fact that the Ibiquity scheme is "on band" is, IMO, not all that
significant. There's nothing magic going on here. The digital signal
simply uses the guard bands around each analog station, at low power.
And a few tweaks to steal some small part of the analog spectrum
optionally, both in the AM and the FM bands.

So yes, the same kind of antenna is used, and you may need "more
antenna," or more careful aiming, to consistently receive the digital
station, compared with the analog counterpart.

This is different from the Euro and Canadian DAB radio system, which has
its own slice up in the UHF or L bands (only L band in Canada).

I tried the Boston Acoustics HD radio radio inside a Tweeter store. It
was obviously happier to receive the analog station that its digital
on-band channels. But they had no outdoor antenna or any such thing. The
digital signal was sort of coming and going on the stations I tried, as
evidenced by the display icon.

Don't know if Canada is also planning to adopt Ibiquity IBOC. In
principle, it could, without affecting the DAB scheme at all.

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