[ICOM] Help needed with noise on HF in the mobile

[William Lambing]

Des, think of the exhaust system as an antenna.  The tips ... and actually the entire system is ungrounded except at the engine.  As you know antennas radiate .... so does the exhaust system. GM, in their infinite wisdom at reducing mechanical noise, floats stuff in rubber composite isolators.  That relates to ... no ground.

Keep in mind also, since yours is up front, the hood could be part of the problem.

I chose brass, since wide brass has very low inductance.  Braid, after a while exposed to elememts, becomes a bunch of individual wires, not a big strap.

Bill, W0LPQ