> Phil,
>
> Answer this question please. At 1500 Watts, your RMS RF voltage is 273.86
> Volts.
> So why do you say that RG-58 is only good for 350 Watts. Even the crappy
> stuff you mention is capable of handling 300 Volts RMS. 273.86 Volts RMS is
> less than 300 last time I checked.
Don't ask me...this is the MANUFACTURER'S rating for 30 mhz!
> > All coax has loss, which is dissapated in heat. Add significant swr
> losses and
> > the dielectric heating begins. This causes migration of the center
> conductor
> > toward
> > the outer conductor, especially where the coax makes a turn. Then you have
> an
> > increasing spiral of more heating at the point of the impedance bump in
> the
> > line.
>
> Agree with that.
>
> > >
> > > > My application is a 12" run of coax from the output of my Pi-L tank to
> the
> > > > vacuum antenna relay which could handle at least 1500 watts out, key
> down.
> >
> > The RG-8X is a foam dielectric cable, and is less robust @ RF and only .3
> db
> > less loss per 100' than solid dielectric RG-58. Making bends with foam
> > dielectric cable inside an RF deck is an invitation to conductor migration
> due to the
> > ambient
> > heat in the deck.
>
> Good point. I never thought of that. But please explain how RG-58 cannot
> "handle" 1500 Watts of RF which is only an RMS voltage of 273 Volts.
For the same reason your wife's hair dryer is not wired with a #22 AWG cord.
Plus 1500 watts is 5 times what the manufacrurer rates the cable @ 30 mhz.
(((73)))
Phil, K5PC
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