[TowerTalk] Lightning protection (?) for Ameritron RCS-10, antenna switch

[Howard Hoyt]

Hey Pete,

As Rob mentioned this technique adds series inductance to the path of 
lightning.  What is more critical than even the loops is a low impedance 
ground from the arrestor in circuit before the loops.  If implemented 
correctly the combined circuit delays the lightning pulse until the gas 
tube establishes its plasma and lowers the voltage on the coax to that 
of the tubes firing voltage (plus rise due to current through the 
tube).  An added benefit of the series inductance is the spreading of 
energy over time, limiting the peak voltage seen by the transmitter.

In broadcast installations I have done this with large #31 ferrite cores 
on the loops for added inductance as recommended by manufacturers.  The 
outcome after years in service has been a few destroyed gas tube 
cartridges, but no damage to the transmitters.

Cheers & 73,
Howie / WA4PSC