Re: [time-nuts] GPS multipath

2014-08-09 Thread Magnus Danielson
Jim, On 08/09/2014 07:02 PM, Jim Lux wrote: On 8/9/14, 9:33 AM, Magnus Danielson wrote: Jim, On 08/09/2014 05:31 PM, Jim Lux wrote: Clarifying my previous question.. There's no doubt that multipath exists, and how to test is fairly straightforward, whether with multiple antennas, cables, or w

Re: [time-nuts] GPS multipath

2014-08-09 Thread Jim Lux
On 8/9/14, 9:33 AM, Magnus Danielson wrote: Jim, On 08/09/2014 05:31 PM, Jim Lux wrote: Clarifying my previous question.. There's no doubt that multipath exists, and how to test is fairly straightforward, whether with multiple antennas, cables, or waving cookie sheets around.. Ultimately,

Re: [time-nuts] GPS multipath

2014-08-09 Thread Tom Miller
Don't forget that the polarity of the reflection will reverse. RCP > LCP. and a >20 dB loss will occur. Tom - Original Message - From: "Jim Lux" To: "Discussion of precise time and frequency measurement" Sent: Saturday, August 09, 2014 11:31 AM Sub

Re: [time-nuts] GPS multipath

2014-08-09 Thread Magnus Danielson
Jim, On 08/09/2014 05:31 PM, Jim Lux wrote: Clarifying my previous question.. There's no doubt that multipath exists, and how to test is fairly straightforward, whether with multiple antennas, cables, or waving cookie sheets around.. What I was really asking is if anyone had observed this in th

[time-nuts] GPS multipath

2014-08-09 Thread Jim Lux
Clarifying my previous question.. There's no doubt that multipath exists, and how to test is fairly straightforward, whether with multiple antennas, cables, or waving cookie sheets around.. What I was really asking is if anyone had observed this in the output of their GPS receiver. That is,

Re: [time-nuts] GPS Multipath from airplanes

2014-01-08 Thread Chris Albertson
It is much more likely that the fade out is due to the changing satellite geometry. Some of them come into view and other go out of view. If your antenna site is not good there might be times where only a few are in view or at low elevation. If there is multi path off a plane it would last only

[time-nuts] GPS Multipath from airplanes

2014-01-08 Thread Hal Murray
I live 20 miles south of San Francisco airport. It's common to see a 747 size plane flying low nearby as they head for the landing queue. My GPS antennas/receivers are not located in great places. They fade out occasionally. Some times are longer than others and such, but short dropouts are