[TowerTalk] Capacitors To Tune 160 Vertical

[Martin Ewing - AA6E]

Let me jump in with a pet peeve.  I know Jim knows better, but there are 
few components that know or care how much power is "pumped through" 
them, although people often speak as if they did.

Capacitors, inductors, coax, switches, and what-have-you have voltage 
and current ratings, but not "power" -- unless referred to a specific 
impedance.  They would have power _dissipation_ ratings, but that's a 
different number.

In this case, it's the capacitor's current rating that is in question. 
Your 1 kW is 4.5 A @ 50 ohms, but it might be 3.2 A @ 100 ohms, or 
whatever.  Same idea applies to voltage ratings.  A corollary: A 
component (switch, ferrite, etc) that handles 1 kW into 50 ohms (VSWR 
1.0) may not handle 1 kW with VSWR 2.0.

Sorry to interrupt the proceedings with such pedantics!

73 Martin AA6E

Jim Brown wrote:
> ...  I began with two .0047 400V dipped micas in
> series, and pumped 1 kW through them for a few minutes. They got 
> warm, as one would suspect, but no sign of overheating.