Re: [IRCA] WOR and IBOC

[Scott Fybush <scott@xxxxxxxxxx>]

Gil Stacy wrote:
> If WOR is only concerned with the "local" and not dx market, then why does
> it persist in using 50kW at night?  Wouldn't 5-10kW at night serve its local
> market?  

I keep seeing this idea come up, and it's worth a response: no, 5 or 10 
kW is no longer enough for a viable full-market AM signal in *any* large 
city these days.

If you've never driven around midtown Manhattan or Chicago's Loop while 
trying to listen to AM radio, this may not seem like an obvious concept. 
If you have - and if you're seeing things from the station's 
perspective, not a DX perspective - you'll start wondering why the FCC 
doesn't authorize 100 or 250 kW on AM.

Particularly in New York, where ground conductivity is abysmally bad 
(Manhattan is one big lump of solid rock, after all), 50 kW is barely 
enough to overcome the combination of massive electrical noise and 
steel-framed buildings that wreaks havoc with AM reception. Even so, 
reception is highly variable. WCBS and WFAN, with their transmitter site 
in Long Island Sound off the Bronx/Westchester line, are often 
completely inaudible in a car driving around Manhattan's Upper West 
Side, thanks to the almost nonexistent ground conductivity of northern 
Manhattan. WQEW, with its Queens transmitter site, is even worse.

The same is true, on the opposite side, for most of the New Jersey-based 
AMs (WOR, WABC, WINS, WEPN, WBBR) on the East Side of Manhattan.

And none of those stations does well at all in penetrating the 
skyscrapers of Midtown or the Financial District. WOR probably does the 
best at penetrating Lower Manhattan, thanks to a transmitter site 
directly across the Hudson and the massive amount of RF it pumps out of 
its directional array aimed east.

Dial the power back to 5 kW on any of those stations and they'd simply 
disappear from the dial in large parts of the city, just as 
lower-powered Jersey-sited stations like WNYC 820, WWRV 1330 and WZRC 
1480 already do. Want to see the remaining successful AM stations go out 
of business in a hurry? That would be a good place to start.

Even in smaller markets, it takes a lot of RF to give an AM station a 
viable signal as communities keep sprawling and as the spectrum keeps 
getting noisier. It's no coincidence that the markets where AM is now 
least successful - think Atlanta or Washington, for instance, but also 
places like Winston-Salem/Greensboro - are the same markets where there 
are few (or even no) AM signals that are powerful enough to cover the 
whole market. Conversely, markets such as San Francisco or Chicago, with 
many high-power, well-sited AMs, still routinely have numerous AM 
signals at or near the top of the ratings.

The fact that all that RF generates lots of skywave, in addition to the 
desired powerful groundwave, is considered an unfortunate side effect by 
many of today's engineers and the management above them. Too few of them 
understand - as we DXers do - that long-range propagation is simply what 
mediumwave RF does, by its nature, and that it can't be eliminated by 
fiat...which is kind of how we ended up in this pickle now.

s

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