[BC] I don't want to go away

[DANA PUOPOLO]

IBOC FM works great in the lab, and in the desert, where there are very few
short spaced stations. In the east and in CA, it will fail miserably.
Here's an example, extreme but nonetheless real. There are two full class B
stations in metro NYC that are first adjacents and but 35-40 miles apart. The
frequencies involved are 103.3 and 103.5. The 103.5 is highly rated WKTU, a
Clear Channel station. The other station is WPRB, owned by Princeton College.
Imagine what's going to happen to the space between these two when both light
up IBOC! Millions of people in New Jersey are not going to hear their favorite
stations any more. It most certainly will hurt WKTU's ratings in NYC, likely
costing Clear Channel millions of dollars.

Check it out for yourself:

http://www.radio-locator.com/cgi-bin/pat?call=WPRB&service=FM&status=L&hours=U

http://www.radio-locator.com/cgi-bin/pat?call=WPRB&service=FM&status=L&hours=U

This scenario will be repeated in many east coast markets.

And this is the FM IBOC, thre better of the two (at least in my opinion).

-D



------ Original Message ------
Received: Sun, 22 Jan 2006 08:48:18 AM PST
From: Barry McLarnon <bdm at bdmcomm.ca>
To: "Broadcasters' Mailing List" <broadcast at radiolists.net>
Subject: Re: [BC] I don't want to go away

On Saturday 21 January 2006 23:06, Steve wrote:
> I love your idea about freezing the number of stations currently lit
> becoming the test base. This will keep the horse in the barn until all
> the bugs are worked out. (of course this is so simple someone missed it)
> Is there someone in this group who could petition the commission in the
> name of this fine group? OR am I just p***ing in the wind?

Ah, that's the rub: this is not a debugging exercise.  We're faced not with 
bugs, but a fundamental design flaw.  There is no engineering solution, 
short of throwing the system on the scrap heap and starting over.

The hybrid FM IBOC system is a nasty design that spews all of its digital 
noise on the adjacent channels.  A case can be made, however, that there 
is a worthwhile tradeoff here.  Analog coverage will be negatively 
impacted in some cases, but one gains the capability of delivering 
multiple audio services that are relatively immune to multipath problems.
There will definitely be some losers on the FM band (rimshots, LPFM's, 
etc.), but it can at least be argued that it is an overall win for the 
industry.

No such argument applies to the AM IBOC system.  The AM band is totally 
unsuitable for the hybrid approach that uses the adjacent channels for the 
digital add-on.  It's simply a train wreck.  Any competent communications 
engineer who did a thorough analysis of the available data back in 
2000-2001 could have predicted this fiasco, but it's here today because 
the NAB insisted that there had to be an IBOC system for both bands, no 
matter the cost.

Barry

-- 
Barry McLarnon VE3JF  Ottawa, ON


_______________________________________________
This is the BROADCAST mailing list
To send to the list, email: broadcast at radiolists.net
For sub changes, archives and info on this other lists:
http://www.radiolists.net/