[BC] Power handling of 1 5/8 foam coax.

[Dale H. Cook]

At 12:38 AM 2/18/2007, Dana  Puopolo wrote:

>Can 1 5/8 foam coax handle 50 kW at 125% + AM modulation? The frequency
>involved is 880 kHz.  If so, what is the safety margin?

Dana -

Andrew LDF7-50A 1-5/8" foam Heliax is rated for 143 kw average power 
at 1 MHz, and 145 kw peak power. That yields a derated carrier power 
of just under 27 kw at 125% modulation with unity VSWR and normal 
ambient temperature.

The power derating formula for AM is Pmax = Ppk / ((1+M)^2 * VSWR), 
where Pmax is derated carrier power, Ppk is rated peak power, and M 
is the modulation index (1.0 = 100%).

Dale H. Cook, Chief Engineer, Centennial Broadcasting, 
Roanoke/Lynchburg, VA - WZZI / WZZU / WLNI / WLEQ
http://members.cox.net/dalehcook/starcity.shtml