[RFI] Rcvr burn-out from HV field

i4jmy@iol.it i4jmy@iol.it
Wed, 5 Sep 2001 10:04:26 +0200

The only way I can image something like that can happen is with an 
extremely high impedance device coupled DC (or very low freq. AC) and a 
transient spike in the power line, rather than field at 60 Hz. 
It's hard anyway to imagine a front end design that uses something like 
a FET with 10 MOhm gate impedance and coupled to the antenna input with 
only a capacitor and without any kind of filter. Such a front end will 
respond to transients beeing only limited by the coax line capacitance 
(small if the line is short), will behave like a broad band amplifier 
(similar to those used in the so called "active antennas") and its IMD 
products could be really very high. 
For transient protection and a *primitive* high pass filtering, a few 
uH inductor inside the rig (i.e. a VK200), just across the antenna 
terminals/connector, will solve this problem and will be transparent to 
VHF/UHF, rx and tx.

Mauri I4JMY