Re: [IRCA] The sky is not falling, and the hobby's far from dead

[Russ Edmunds <wb2bjh@xxxxxxxxx>]

--- Andrea Lawendel <lawendel@xxxxxxxxx> wrote:

> On 3/23/07, Paul Crankshaw <paulc@xxxxxxxxxxx> wrote:
> >
> > Here in Europe there are a few DRM stations which I presume are the
> > equivalent of IBOC.
> 
> 
> Paul,
> 
> I believe IBOC it's even worse. DRM as pure digital modulation
> maintains a
> spectral occupancy of 9 kHz, which is bad in cases like the one
> you're
> referring to. If I'm not mistaken, IBOC being a hybrid mode, it adds
> 10 kHz
> of digital modulations to each 5 kHz of analogue sidebands, for a
> total
> occupancy of 30 kHz. Digital side bands have lower power, but I can
> assure
> their effect in the daytime is huge. 

*** Pretty much correct. What we have with IBOC is a hybrid mode where
the analog signal occpies the portion of the spectrum it always did,
and the digital signal occupies two bands on either side, which
significantly increases the total bandwidth. 

DRM as you have it in Europe contains only the digital signal - no
double sidebands - so it occupies less bandwidth.



Russ Edmunds
Blue Bell, PA ( 360' ASL )
[15 mi NNW of Philadelphia]
40:08:45N; 75:16:04W, Grid FN20id
<wb2bjh@xxxxxxxxx>
FM: Yamaha T-80 & Onkyo T-450RDS w/ APS9B @15'
AM: Hammarlund HQ-150 & 4' FET air core loop


 
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