Re: [IRCA] NAB wants it both ways

["Craig Healy" <bubba@xxxxxxxxxxxxxxxxxxxx>]

> *** Time for a rhetorical question.

How can you tell if a question is rhetorical?  Wait...  Was that....??

> What, exactly, makes anyone think
> that since typical HD radios cannot receive HD signals at similar
> distances to analog without external antennas, the reception will
> somehow be any better in vehicle radios ??

Perhaps it's simple denial.  I have had two different HD Radios, and
consulted with a couple of my fellow broadcast engineers that have radios of
different brands.  Our results have been the same.  Coverage is about half
the radius of a good quality, perfectly listenable analog signal.  I'm not
talking about an analog signal that a DXer could handle, but a signal that a
DXers *spouse* could handle.  (grin)  I cannot believe that a realistic
evaluation would show something different.

Now, I am going to play devil's advocate here, much as I don't want to..

Right now digital power is 1% of analog.  Coverage increases as the square
root of the power increase.  Double the coverage, four times the power.
With the coverage radius at half the analog, the area covered is 1/4.  So,
to equal the coverage of the analog, it would take 16 times the power - or
16% of analog.  That's really optimistic considering the interference
potential of the digital signal.  So, 20% maybe for an all-digital signal to
equal analog?  10kw from a 50kw station?  Does anyone know if that has ever
been tried?  I did ask a local engineer if his station was capable of an
all-digital transmission, and he didn't think so.  Someone said a Broadcast
Electronics transmitter could, but a Harris rig could not.

What I'm leading up to is to see if there is anyone out there who would
consider doing an all digital test some morning for those of us who do have
the radios.  This is assuming that the radios out there are capable of
decoding an all-digital transmission.  I simply do not know.  The firmware
on those may only be able to handle the interim adjacent channel signals.

Well, if IBOC does become the Law Of The Land, maybe I'll just go back to
selling virtual real estate in Second Life...

Craig Healy
Providence, RI

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