Google 'GPS testing notices'
On Mon, Jul 11, 2022 at 1:15 PM jeanmichel.friedt--- via time-nuts < time-nuts@lists.febo.com> wrote: > for what it's worth ... the UK gov. is nice enough to warn about GPS > jamming > exercises > https://www.ofcom.org.uk/spectrum/information/gps-jamming-exercises > not sure about the US of A announcements on such activities. At least in > France > I have never seen such warnings. > > Best, JM > > -- > JM Friedt, FEMTO-ST Time & Frequency, 26 rue de l'Epitaphe, 25000 > Besancon, France > > July 11, 2022 7:42 PM, "Bob kb8tq via time-nuts" <time-nuts@lists.febo.com> > wrote: > > > Hi > > > > Are all the receivers the same type / model? If so what are they? > Various > > receivers made over the last 20 years have some “issues” that can pop > up. > > > > Is the antenna gain properly matched to the needs of the receiver? Some > > are designed for a “target gain” of 20 db, others 30, some 50. Match a > > 20 db receiver with a 50 db antenna …. you have issues. > > > > Are all the hilltops in common view of each other? Somebody jamming their > > ankle bracelet could be the simple answer if they are …. > > > > Just what overloads this or that receiver often is a bit obscure. Most > are pretty > > good at taking out CW tones. It often takes something a bit more complex > > to drive them insane. This makes testing a bit exciting. > > > > Lots of strange and weird possibilities. > > > > Bob > > > >> On Jul 10, 2022, at 3:19 PM, skipp Isaham via time-nuts < > time-nuts@lists.febo.com> wrote: > >> > >> Hello to the Group, > >> > >> I'd like to get some opinions and war stories regarding GPS reliability > at > >> high RF level and elevation locations. > >> > >> Background: Three different hill-top GPS receivers, all different > types, using > >> different antennas mounted on an outside fixiture, plain view of the > open sky, > >> all stopped working. > >> > >> Test antennas were brought in and placed on a fixture well away from the > >> original antennas, the recevers went back in to capture and lock. > >> > >> From what I understand, the original antennas are what I would call > straight > >> preamp with no pre-selection / filtering. > >> > >> The ordered and now inbound replacements are said to contain a SAW > filter > >> system. It is the intent of the client to just place these "improved > antennas" in > >> to service and get on with life. > >> > >> I would suspect a GPS antenna (and receiver) could be subject to RF > overload > >> or blocking, however, we're assuming nothing major has changed at the > site, nor > >> any nearby location. One might think there are more GPS receivers being > pushed > >> out of reliable operation by the world around them, I'm just not > hearing those stories > >> from a lot of people using them (GPS receivers). > >> > >> Any new install GPS receiver antenna ordered will/should contain some > pre-selection > >> to potentially avoid a problem, even some years down the road? Seems > like that's > >> where things are going... no more off the shelf, wide band, (hot) > preamplified GPS antennas > >> in busy locations? > >> > >> Thank you in advance for any related comments and/or opions ... > >> > >> cheers, > >> > >> skipp > >> > >> skipp025 at jah who dot calm > >> _______________________________________________ > >> time-nuts mailing list -- time-nuts@lists.febo.com > >> To unsubscribe send an email to time-nuts-le...@lists.febo.com > > > > _______________________________________________ > > time-nuts mailing list -- time-nuts@lists.febo.com > > To unsubscribe send an email to time-nuts-le...@lists.febo.com > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe send an email to time-nuts-le...@lists.febo.com _______________________________________________ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe send an email to time-nuts-le...@lists.febo.com