Colin,
Based on my experience with two different HD radios, it's a pretty fragile
mode on AM. In my area, broadcasters are still turning off HD at night, so
I can't speak to such things as selective fading, but during the day, I can
only get two stations with any reliability. Just about any kind of static
or noise sends the radios back into analog mode. Maybe some day there will
be better circuitry for coping with noise, but it's not there at the moment.
Steve
----- Original Message -----
From: "Colin McDonald" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Thursday, April 05, 2007 18:21
Subject: Re: Fw: [NYDXA-List] FCC Approves IBOC Go Ahead
> So, i suspect that high gain AM antennas with built in preamps will become
> much cheaper and will be recommended.
> I can just imagine the advertizing for them now.
> The whole debate around weather you will need a good signal all the time
> strikes me as a bit odd, since, even though it is A M, the digital signal
> won't have to be nearly as strong to be decoded when compared to an audio
> signal.
> I also expect there are noise cancelling circuits built into the iboc
> radios
> to attempt to eliminate noise from outside the pass band that the digital
> signal will need.
> I don't know allot about the type of digital signal it is, but if it is
> like
> most digital streams, it will only take up a certain segment of the audio
> band and everything else can be blanked out.
> So, phase shifting and fading may have already been compensated for.
> Am i totally wrong about all this?
> It seems to me that engineers designing iboc and those intending to use
> it,
> aren't a bunch of intelectually challenged morons who don't know the first
> thing about RF communications. I am posative much of the problems brought
> up here have been addressed and worked out already.
> 73 Colin, V A6BKX
> ----- Original Message -----
> From: "Steve Dresser" <[log in to unmask]>
> To: <[log in to unmask]>
> Sent: Thursday, April 05, 2007 11:22 AM
> Subject: Re: Fw: [NYDXA-List] FCC Approves IBOC Go Ahead
>
>
>> Steve,
>>
>> I've had two HD radios for about a month now, and from what I've seen,
>> you
>> need a pretty noise-free signal to make it work reliably, and that's
>> especially true for AM where, ironically, there's more noise. On FM, it
>> works quite well with my tuner, but that's because I have a 9-element
>> beam
>> up on the roof. If I didn't have that antenna, digital radio would
>> hardly
>> be worth considering because I'd have a hard time even with many local
>> stations. Let's face it, you can't get away from the noise unless the
>> antenna is outside, and noise is the enemy here.
>>
>> Steve
>>
>> ----- Original Message -----
>> From: "Steve" <[log in to unmask]>
>> To: <[log in to unmask]>
>> Sent: Thursday, April 05, 2007 11:18
>> Subject: Re: Fw: [NYDXA-List] FCC Approves IBOC Go Ahead
>>
>>
>> > From what I recall, from an older article in one of the hifi mags, =
>> > digital AM doesn't have nearly the range of a standard AM signal. =
>> > Also,, I suspect the adjacent channel interference will mean that a =
>> > digital stream will need to be fairly strong to work.
>> >
>> > Steve, K8SP
>> >
>> >
>> >
>>
>>
>> --
>> No virus found in this incoming message.
>> Checked by AVG Free Edition.
>> Version: 7.5.446 / Virus Database: 268.18.26/746 - Release Date: 4/4/2007
> 1:09 PM
>>
>>
>
>
>
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