[BC] X-Banders - Was: Can traditional AM and IBOC co-exist?

[cldube]

I guess that's why Disney's WHTK 1650 in VA rockets up to the northeast 
during critical hours?
Sometimes I can get them in the Hartford area better than Hartfords own 
WDZK.

Interesting points regarding the mV/m/kW figures in these examples.

Thanks for the tutorial

Chuck

----- Original Message ----- 
From: <PeterH5322 at aol.com>
To: <broadcast at radiolists.net>
Sent: Monday, July 11, 2005 1:31 PM
Subject: [BC] X-Banders - Was: Can traditional AM and IBOC co-exist?


>
>>Why is it that x-banders also tend to work with shorter towers? One would
> think
>>that given the wavelength, they'd want to utilize the benefit of a shorter
> structure
>>inherently. Call me naive- I'm very curious!
>
> X-banders are Class Bs, and Class Bs are required as a minimum (and are
> permitted as a maximum) 281.63 mV/m/kW at 1 km.
>
> This is about 80 degrees, give or take.
>
> While the Commish seems to let X-banders operate 10/1 kW with radiators
> of a "reasonable" height, say, 80 to 110 degrees, with 90 degrees being
> customary, X-banders who install, or are diplexed with taller sticks,
> say, 180 or 200 or 225 degrees, all good heights for this service, are
> still bound by 281.63 mV/m/kW at 1 km.
>
> Let's say I diplex with a station which gives me a super-tall stick, such
> as 225 degrees, which is about 440 mV/m/kW at 1 km.
>
> 281.63 mV/m/kW at 1 km is imposed as a limit at night (and could be
> imposed as a limit during days, I suppose, if there were adjacent channel
> issues), and such a station would be allowed about 0.4 kW, maximum, as
> 400 watts into a 225 degree stick produces about the same horizontal
> field as does 1 kW into a minimum conforming radiator.
>
> The maximum power permitted in such a situation is:
>
> Pmax = 1000 watts * (281.63 / Actual Efficiency)^2
>
> For a 225 degree, 440 mV/m/kW at 1 km stick,
>
> Pmax = 1000 watts * (281.63 / 440)^2 = 407 watts
>
> I can point to one X-bander which has a 220 degree stick, and operates
> with 490 watts.
>
>
> One incredible fact is Class Cs sometimes get away with 225 degree
> towers, and yet are still allowed 1/1 kW.
>
> The effective power from such a station is remarkable ... about 3,300
> watts day and night ... ND, too.
>
> More than lots of ex-Class III Class Bs.
>
> Of course, their NIF may suck :-) .
>
>
>
>
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