[Elecraft] Balun BL2

[jsodus at comcast.net]

Hello, 
I'm contemplating buying the BL2 balun. 
It would be connected to 450-ohm transmission-line, which would go to a version of W1AB's "killer-antenna", sized for 20m on a 31' jackite-pole. 

A reviewer of the BL2, on eham five years ago, commented about heat and signal-loss. 
The heat and signal-loss concern me, not at the QRP-level but higher wattage. 
I realize it is spec'd at 250 W but how hot does it get? 

I've looked for data about insertion-loss for the BL2 and came up short there. 
Hopefully someone has measured the insertion-loss and could share that data. 

The "elecraft BL2 assembly and operating manual" has the cores as ferrite material. 
But ferrites exhibit non-linear properties, so the loss may be a function, not only of frequency, but also drive-level. 
Insertion-loss shows up as heat and that heat affects the properties of the ferrite. 

As I wrote above, I'm not concerned about QRP operation. 
If I put it into operation on FD and but take my KX3 home for the day, what happens if a club-member connects his 100+ W rig to the antenna-system to operate thru the night? 
TIA for any reply. 

73 Jerry KM3K 
KX3 #6088