[BC] LPFM vs. AM on FM Translators

[Peter Moncure]

Willie wrote:
> A nice idea, but in our case, it wouldn't help. WTWP's signal, typically, 
> ranges from 1-5mv/m during summer nights. It can peak around 10. In winter, it's 
> much higher, averaging 5-10, with peaks to 20. I've seen it happen many times! 
>   
May I point out that the highest land value for WTWP at night, which 
occurs on the barrier islands west of Elizabeth City, NC, is predicted 
by FCC to be only 1.77 mV/M?  I doubt the proponents of IBUZ have taken 
real skywave values into account.  (you can see the picture at 
http://radiosoft.com/WTWPNight.jpg)  As for your math guru questions 
(I'm not one, but there are several working here...), here's the scoop.  
If you consider usable signal cochannel to be 20:1 (debatable), and 
there's a 5 or 10 mV/M interferer, you would need 100 or 200 mV/M.  
These contour distances (assuming an omnidirectional pattern) are 572 
and 335 meters, respectively.  At 5 kW, they are 1981 and 1281 meters, 
respectively.  With a mile at 1609.3 meters, you're a good guesser.  
However, I've measured quite a few radials down by the coast, and I'd 
say your conductivity is no more than 0.3 mV/M in most places, if that.

-- 
Peter Moncure, RadioSoft