[opendtv] Re: HDradio?

  • From: "Manfredi, Albert E" <albert.e.manfredi@xxxxxxxxxx>
  • To: "opendtv@xxxxxxxxxxxxx" <opendtv@xxxxxxxxxxxxx>
  • Date: Tue, 4 Dec 2012 19:11:13 -0600

Cliff Benham wrote:

> I think HD radio performance depends a lot on how close you
> are to the signal source.
> I have an HD radio in the car and can't get any AM or FM
> reception out in the country where I live, 39 miles from
> Philadelphia and 52 from Baltimore. When I drive toward Philly,
> I begin to get good reception when I'm within 15 miles of the city.
> The AM reception is not good anywhere I drive.

Probably due to the severe ERP restrictions imposed by the hybrid mode 
requirements. I would actually have preferred if they moved at least some 
stations to their own frequency channel (where available slots exist), and 
transmit in pure digital, at full power. IIRC, the AM power restriction is even 
more than FM. It's 23 dB down in the FM band, and 35 dB down in AM, I believe. 
Should anyone wonder why reception in the boonies might be an issue?

> For me, HD radio does not begin to measure up to standard AM
> and FM radio reception in the car or at home in the country.

Like all digital RF, it can handily beat analog in the right circumstances, but 
it suffers from a digital cliff. Still, I manage to use my two mixed Antennas 
Direct DB4 antennas, in fireplace, ground floor, theoretically a UHF-only 
design, also to receive HD Radio. And the signal strength bars, in digital, go 
to full. But the towers are probably 12 miles or so distant, so that would 
agree with your experience.

> One other complaint I have about HD AM radio is that its digital
> sidebands prevent me from listening to some distant AM stations I
> used to pickup easily with a high quality hi-fidelity McIntosh
> radio tuner. These distant stations are now blanked out by the
> noise of the local digital AM sidebands.

Yes, in AM especially, chewing up two adjacent frequency slots doesn't seem 
like a great idea. But again, in pure digital, it wouldn't be a problem. And AM 
would actually sound good, where you can actually hear sibilant sounds.

With no plan to phase out analog radio, I'm not sure what will happen. You 
SHOULD complain to the FCC. Tell them to phase out analog radio!!


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