Interference to GPS

Abstract

I read Captain Gyldeń's account of failure of his GPS set (Vol. 50, 328, May 1997) with some interest. A few days earlier we had had a few thunderstorms while I had my personal hand-held GPS running, using its own built-in antenna and a 12 volt battery. It was lying on a bench inside a wooden hut where I keep some of my amateur radio equipment. After one particularly close flash and bang, which produced a one-inch spark from my transceiver antenna, the transceiver locked up and stopped responding to keyboard commands. Then I noticed the GPS set had also stopped working, showing only random symbols on its readout. I feared the worst but, after switching them both off, leaving them for a few minutes, and then back on again, they worked perfectly.Microprocessors locking up in strong local electrostatic fields, perhaps? Maybe if I had simply left them alone they would have started working again after the charge had leaked away. Next time I nearly get hit by lightning I'll try it.

Constraints on dark energy evolution

“…The sound speed was kept constant. We did not use the reduced quantity R, which is closely related to the angular distance to the CMB, and which is the most changed quantity when adding a cosmological constant (Blanchard 1984;Efstathiou & Bond 1999). We used the 5-year release (Nolta et al 2009) and the ACBAR data (Reichardt et al 2008) for additional stringent constraint on small scales.…”