Gary, good job there.
I find your black magic comment on the mark. My shack is built with all
the correct station engineering principles. Antennas are nearly 300
feet out. Single point ground into a breaker box located within feet of
the shack which is also at the mains entry point to the house. Monster
ground system at the shack. All the other stuff.
Against that I've run 4 different tube amps in that location without a
single issue. I picked up a shiny new SS amp and fried the control
board in my aircon blower and high-tech thermostat working CW on 40m.
Absolute correlation between key down and smoke.
I'm sure I could have tracked down whatever was at the root cause. I
have the gear to do it. But it was easier (and a lot more XYL friendly)
to get the aircon back in action - FAST. Replaced the thermostat and the
controller board. But this time I bypassed all the I/O on the two
units. Been all quiet on the house electronics front since then.
I attribute it to RF black magic. But I'm sure there was some RF
coupling path in there somehow that the unique combination of that amp
and the rest of the infrastructure brought together. Pretty weird!
73/jeff/ac0c
alpha-charlie-zero-charlie
www.ac0c.com
On 2/4/20 12:59 PM, Gary H wrote:
Well thanks all for the advice. As for grounds I have two 8 ft ground
rods and large radial field bonded to shack ground bus with short
heavy wire and connected back to mains entrance ground.
We checked both amps with a spectrum analyzer all the way to 6 GHz.
Tube amp was not real clean but within specs for a 30 year old
technology. The Hercules II SS amp was very clean. So why Hercules
bother his motion light and heath does not remains a mystery.
I tried three different antennas. One coax fed dipole, one open wire
fed dipole and one vertical. Only the vertical did not cause his
lights to come on with either amp. My ants are 100 feet from his
motion lights and 80 ft in the air. Vert is ground mounted at radial
field.
I have fixed the problem by relocating the ends of the antennas
another 50 feet further away. I not longer bother his light. Why
this happens will have to be chalked up to RF black magic and his 9.99
walmart motion lights.
Thanks all
Gary K4MT
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