Re: [IRCA] Another perspective on AM IBOC, from the broadcasters' mailing list

[Barry McLarnon <bdm@xxxxxxxxxx>]

On Tuesday 27 March 2007 21:11, Scott Fybush wrote:
> Patrick Martin wrote:
> > Barry & Chuck,
> >
> > Then in layman's terms, we have two choices if IBOC becomes a reality
> > across the band. One, we move on to another band or move pyhsically to
> > another location. Any other choices?
>
> That's a somewhat pessimistic way of putting it, which is very much in
> keeping with the way these threads seem to be going.

I suppose I'm one of the ones you're pointing the finger at, but, believe me, 
I'm not going out of my way to be relentlessly pessimistic.  I just call 'em 
as I see 'em.

> I'm involved in other hobbies that are slowly being eroded by changing
> times and changing technologies - coin collecting, for instance, where
> clubs like mine (which is about to celebrate its centennial) are coming
> to terms with dwindling (and aging) membership rosters and a lack of new
> blood.

True enough, but in the present case, we're faced with more of an overnight 
ka-boom than a gradual dwindling.  And, like Craig, my concerns are for the 
future viability of the service, not just the hobby aspect.

> But they've got nothing on this crowd when it comes to turning over
> every possible rock to find the gloomiest possible way to reframe any
> discussion of what might - or might not - happen.

Sorry you feel that way, but neither you nor any of the other 'glass is half 
full' folks have given me any solid reasons to feel optimistic.  It's all 
just wishin' and hopin'... meanwhile, I'll continue to state the facts as I 
see them.

> I can certainly understand why there's ample cause for concern. I'm
> worried, too. What I don't get is the apparent desire to drive the last
> nail into the coffin long before we know how this will actually play out.

Sorry, but we ragtag "nay-sayers" aren't really in a position to drive any 
nails in this particular coffin.  That's being done by the suits who are 
driving this train.

> Here's how I'm looking at the next few years: some frequencies will get
> noisier when night IBOC starts. A handful will become unusable - 1020 in
> the northeast, for instance, when WBZ kicks on at night. (1040's already
> unusable for me, thanks to my local WYSL.) A fair number of channels
> will have only a few - or no - IBOC signals putting enough power in my
> direction to create any more noise than is already there.

Handful?  I think not - see below.

> But as I keep trying to point out, there's nothing magical about IBOC
> sidebands and skywave. If I can null WWL's 50 kilowatts of analog on
> 870, I'm going to be able to null its 500 watts of digital on 860 and
> 880, too. (If WWL even runs IBOC, which isn't a done deal AFAIK.) Ditto
> for WBT, or KMOX, or WCCO where I am.

Sigh... and, as I keep trying to point out, it's not 500 W, but either 1.3 kW 
or 1.5 kW (depending on a power setting in the AM IBOC standard) on each 1st 
adjacent channel.  Moreover, in terms of interference power in the receiver, 
it's roughly equivalent to a 5 kW AM station on each of those channels.

As for the phasing argument, I think you're missing the point.  When you DX a 
given channel, you generally have to null a dominant station on that channel 
in order to hear what's underneath it.  If an IBOC sideband appears on that 
channel, you can phase it alright, but then what have you got?  That dominant 
signal that you were formerly able to phase.  Game over.  In many cases, you 
can null out the digital noise on a given channel, but that doesn't mean you 
can DX that channel - at least, not in any serious way.  And, in many cases, 
there will be multiple digital sidebands on a given channel, from different 
directions.  Really game over.

> My best guess, based on the stations that already have IBOC installed
> and a few that I know are planning to install it, is that I may
> completely lose between 15 and 20 frequencies when night IBOC kicks in.
> That's not pretty. I'm not happy about it. But for me, at least, it's
> just one more in a series of annoyances that include rising levels of
> ambient electrical noise, an increase in illegal full-power night
> operation, and the breakdown of the clear channels that started decades
> ago, and of which this is just the latest symptom.

I looked at the existing roster of IBOC stations, and based on my experience
with their signal strength here, came up with a list of the channels that I 
expect will become essentially useless for DXing when nighttime IBOC comes to 
pass.  The list contains 63 channels.  63!  That's more than half the 
channels in the band.  The only segment of the band that will be relatively 
unaffected in the short term is 1300-1500.  Whoop-de-doo.

> And you know what? I think of myself as an optimist. Without being a
> Pollyanna about the whole thing, I can at least be interested in
> studying how the system works once it's in operation. Fact is, nobody
> knows exactly what will happen - how many stations will adopt the
> system, how bad the interference will be in the real world, what sort of
> marketplace backlash there might be if and when stations with
> significant skywave audiences lose them to interference...and, as the
> post that started this thread implied, what developments in receiver
> technology might lie in our collective future.

Hey, pessimist or optimist, we'll all be studying this beast.  I wouldn't miss 
it - there's a certain fascination in watching an out of control train as it 
careens toward that cliff. :-)  I don't think any technological developments
will tame this beast, but perhaps litigation will.

>  From the very beginning of the hobby, DXers have learned to adapt to
> changing technologies and changing band conditions. I'd love to have
> been alive and DXing in the 1930s, or even the 1960s, but here I am in
> 2007, at age 35, and I missed those opportunities. I could throw up my
> hands and declare the whole thing dead and go work on upgrading my set
> of commemorative half dollars...or I can try to find some interesting
> challenges in whatever the future holds. I choose the latter.

I'm sure there will continue to be DXing in some sense (casual), but for 
anyone who's really serious about it, I can't see them putting up with the 
aggravation.  It'll be time to move on to other, more rewarding, pursuits.
Me?  I'll hang around for awhile, since I have a professional interest in
this stuff, and besides, there's still a chance some sanity may prevail in the 
long run.

Barry

-- 
Barry McLarnon  VE3JF  Ottawa, ON
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