[Amps] RF ground

[Gary Schafer]

Richard wrote:

>
> €   I use a Hertz antenna  (end-fed multi half-wave; high feed-Z).  Equal
> currents flow into the antenna and the antenna tuner ground.  The lead to
> the ground system is 5' of two-inch wide copper strap (c. 200nH of
> inductance).  Thus, there is an RF voltage drop across the tuner ground
> lead.  If the tuner ground is connected to the radio ground, the radio
> becomes hot with RF.  I installed a coaxial choke balun to prevent RF
> from going back to the radio.

If you got an 18 kA lightning strike the voltage on the ground at your tuner
would rise to around 18 kV due to the impedance of the 5 foot ground lead. That
is assuming you had a perfect ground at the other end of the strap.

73
Gary  K4FMX