[time-nuts] GPS outage? 19:00-2100 UTC Tue

Jim Lux jimlux at earthlink.net
Thu Aug 20 08:18:40 EDT 2015

On 8/19/15 10:12 PM, Hal Murray wrote:
> time at radio.sent.com said:
>> I think that Menlo Park is somewhat under 300 NM (nautical miles) from China
>> Lake (depending on exactly where the test was located), and the expected
>> interference range was about 252 NM. So you might have been at the edge of
>> the affected area. See: http://www.navcen.uscg.gov/pdf/gps/gpsnotices/
>> GPS_Interference.pdf

On the other hand, there is a 4000 m tall mountain range (Sierra Nevada) 
and a lot of other stuff between the two. I'm pretty sure that the 
radius of the circle is for *airborne* platforms, where the jammers are 
in line of sight.  (radar horizon at 30,000 ft is about 250 miles)

It would be truly amazing to get L-band propagation from China Lake to 
Menlo Park.

I'd go for the "trucker with a jammer" scenario

or "malfunctioning equipment oscillating in band" scenario (like the 
Monterey Bay event)


> Thanks.  My measurements on Google maps are are close to 250 miles.  That's
> to the town rather than the boonies out back.
> My antennas are all in poor locations (indoors) rather than good locations so
> I'm probably more sensitive than some of their target users.
> What's the BNM column on that chart?
> What sort of gear would I need to detect a local jammer?

More information about the time-nuts mailing list