[time-nuts] Do ordinary clouds adversely affect GPS reception?
jimlux
jimlux at earthlink.net
Tue Oct 22 13:03:57 UTC 2019
On 10/22/19 2:23 AM, Jim Palfreyman wrote:
> I see no attenuation at 1376 MHz (close to GPS frequency) when observing
> pulsars with a radio telescope. Even the brightest pulsar (Vela) is so much
> fainter than a GPS signal which boom in when they happen to pass into the
> telescope's beam.
>
> It definitely happens at higher frequencies though. Up around 20 GHz it's a
> different story.
>
On a sensitive receiver I operated at 13.402 GHz in New Mexico, I could
easily tell when it was overcast or not by the noise temperature. There
was some discussion about whether we were seeing the physical
temperature of the clouds, or we were seeing a reflection of the earth
off the water particles in the clouds. We didn't go any further, since
our project was to measure a radar signal, but it was interesting.
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