Maybe not killed, but RF Burns were very common when the RF Grounding
System wasn't big enough to support the transmitter.
Bruce in alaska
When I was a MINELANT, we had a problem with the old, wooden minesweepers
that had URC-32, 500W transmitters on them. A sailor was burned quite
badly in his hands when he came in contact between two sections of well-
grounded handrail from the RF induced. The handrail sections had separate
ground paths to ship's ground. They checked out the grounding and it was
all intact and the electricians tasked with the problem were scratching
their heads as to how he could have gotten zapped.
AS 1/4 wavelength back from ship's ground was a virtual open, and that
ground strap, itself, were part of the "handrail antenna", I had a lot of
convincing to them that this was the problem. The two lengths of ground
straps were different, so one hand rail was at a different RF potential
than the other when the transmitter was keyed up.
To satisfy both DC grounding requirements and to stop the RF buildup on the
components, I convinced them to put RF chokes in series with the ground
straps at the handrail end, eliminating the big vertical antenna of the
strap across the wooden hull. Worked great, on all frequencies.
On fiberglass flybridges, all those cables under the helm exposed to the RF
from a nearby HF antenna and its tuner can create havoc to the NMEA network
and everything attached to it. I found one boat where the panel lighting
would glow when the HF transmitter was on the 4 Mhz band as the wiring
resonated just right.
Of course, if the manufacturers would use NMEA's BALANCED specifications,
instead of hooking between one leg of the balanced system and ground for
their NMEA in/out connections, they could help stop the intrusion of RF
into the system in the first place. The "ground" wire hooked to the boat's
battery negative is a great HF antenna up on the flybridge end....
