[Elecraft] 125' EFHWA (was: long wire balan)

[Ron D'Eau Claire]

Absolutely, for QRP levels! 
 
With the high impedances come very high RF voltages - voltages in the
hundreds, even thousands of volts. That's why compact ATU's like the
Elecraft ATU's can't handle those impedances - even if they could affect a
match the voltages would destroy the caps, relays and other components at
any power above a few watts. 
 
There's a reason why the antenna tuners shown in the old textbooks have huge
capacitors and big coils wound on ceramic forms or air-wound and everything
mounted on big ceramic stand-off insulators! That's what is needed when
running more than a couple of watts into a really high-impedance load. 
 
Even at 50 watts I've seen a transmitting variable capacitor with 1/4-inch
(6mm) plate spacing arc over when coupling to a really high-impedance load. 
 
Ron AC7AC
 
-----Original Message-----



Or..... an intermediate simple ATU such as
 
http://www.qrpproject.de/UK/fuchs_ant_.htm
 
This should work?
 
73, Deni
 
F5VJC GM3SKN