Empathy List Archives

BK

Bob kb8tq

Mon, Jul 11, 2022 4:06 PM

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-leave@lists.febo.com

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-leave@lists.febo.com

JF

jeanmichel.friedt@femto-st.fr

Mon, Jul 11, 2022 5:48 PM

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-leave@lists.febo.com

time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe send an email to time-nuts-leave@lists.febo.com

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-leave@lists.febo.com > > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe send an email to time-nuts-leave@lists.febo.com

J

JC

Mon, Jul 11, 2022 6:27 PM

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-leave@lists.febo.com

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-leave@lists.febo.com > > > > _______________________________________________ > > time-nuts mailing list -- time-nuts@lists.febo.com > > To unsubscribe send an email to time-nuts-leave@lists.febo.com > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe send an email to time-nuts-leave@lists.febo.com

BL

Brian Lloyd

Mon, Jul 11, 2022 8:40 PM

On 7/11/22 12:48, jeanmichel.friedt--- via time-nuts 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.

Yes, they do. Still, it is annoying to be piloting an aircraft in
instrument conditions and have GPS go away. When it has happened usually
I am prepared to switch back to VOR navigation.

--

https://www.lloyd.aero

Brian Lloyd
706 Flightline
Spring Branch, TX 78070
brian@lloyd.aero mailto://brian@lloyd.aero
+1.210.620.0011

On 7/11/22 12:48, jeanmichel.friedt--- via time-nuts 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. Yes, they do. Still, it is annoying to be piloting an aircraft in instrument conditions and have GPS go away. When it has happened usually I am prepared to switch back to VOR navigation. -- <https://www.lloyd.aero> Brian Lloyd 706 Flightline Spring Branch, TX 78070 brian@lloyd.aero <mailto://brian@lloyd.aero> +1.210.620.0011

O

Oz-in-DFW

Mon, Jul 11, 2022 9:28 PM

On 7/11/2022 8:43 AM, Andy Talbot via time-nuts wrote:

I also heard a case of a GPS antenna going unstable, oscillating and taking
out most of the boats in a marina.

There have also been several cases of cheap active TV antennas doing the
same thing. There was a case 10 or more years ago that shut down an LA
marina and the Port of Long Beach for several days until it was located.

Oz (in DFW, Texas near the airport)

On 7/11/2022 8:43 AM, Andy Talbot via time-nuts wrote: > I also heard a case of a GPS antenna going unstable, oscillating and taking > out most of the boats in a marina. There have also been several cases of cheap active TV antennas doing the same thing. There was a case 10 or more years ago that shut down an LA marina and the Port of Long Beach for several days until it was located. Oz (in DFW, Texas near the airport)

BK

Bob kb8tq

Mon, Jul 11, 2022 11:14 PM

Hi

These days there are folks who make a living tracking down interference
sources in the vicinity of ports and airports on a contract basis. Many of
the issues are navigation related. Some of it is GPS. Some is other stuff
( like 5 GHz WiFI and radar …)

Bob

On Jul 11, 2022, at 1:28 PM, Oz-in-DFW via time-nuts time-nuts@lists.febo.com wrote:

On 7/11/2022 8:43 AM, Andy Talbot via time-nuts wrote:

I also heard a case of a GPS antenna going unstable, oscillating and taking
out most of the boats in a marina.

There have also been several cases of cheap active TV antennas doing the same thing. There was a case 10 or more years ago that shut down an LA marina and the Port of Long Beach for several days until it was located.

Oz (in DFW, Texas near the airport)

time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe send an email to time-nuts-leave@lists.febo.com

Hi These days there are folks who make a living tracking down interference sources in the vicinity of ports and airports on a contract basis. Many of the issues are navigation related. Some of it is GPS. Some is other stuff ( like 5 GHz WiFI and radar …) Bob > On Jul 11, 2022, at 1:28 PM, Oz-in-DFW via time-nuts <time-nuts@lists.febo.com> wrote: > > On 7/11/2022 8:43 AM, Andy Talbot via time-nuts wrote: >> I also heard a case of a GPS antenna going unstable, oscillating and taking >> out most of the boats in a marina. > There have also been several cases of cheap active TV antennas doing the same thing. There was a case 10 or more years ago that shut down an LA marina and the Port of Long Beach for several days until it was located. > > Oz (in DFW, Texas near the airport) > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe send an email to time-nuts-leave@lists.febo.com

MW

Matthias Welwarsky

Tue, Jul 12, 2022 7:08 AM

Hi,

if you're worried about in-band interference, the 23cm HAM radio band is
reasonably close to the L1 GPS frequency. When I was still active in packet
radio back in the days, our digipeater DB0DAR lost an interlink due to
interference with a precision GPS receiver in use by another university
institute. We had to shut it down. I think they operated a DGPS site at the
time and our link traffic caused errors in the correction data. Or something.

BR,
Matthias

On Montag, 11. Juli 2022 01:19:18 CEST skipp Isaham via time-nuts 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-leave@lists.febo.com

Hi, if you're worried about in-band interference, the 23cm HAM radio band is reasonably close to the L1 GPS frequency. When I was still active in packet radio back in the days, our digipeater DB0DAR lost an interlink due to interference with a precision GPS receiver in use by another university institute. We had to shut it down. I think they operated a DGPS site at the time and our link traffic caused errors in the correction data. Or something. BR, Matthias On Montag, 11. Juli 2022 01:19:18 CEST skipp Isaham via time-nuts 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-leave@lists.febo.com

SM

Scott McGrath

Tue, Jul 12, 2022 11:18 AM

I’m going to bring up jamming here as 1) i live directly under a military air route. 2) a local OTR trucker brings regularly scheduled jamming when he leaves/arrives home.

Your client could also be in proximity to a ‘prepper’ who is running a GPS jammer to prevent ‘three letter agencies’ from tracking them. Or a trucker doing the same and forgetting to shut down their jammer. GPS jammers are available ‘under the counter’ at virtually every truck stop in the US.

Yes it’s highly illegal and disrespectful of other system users and in the prepper case will eventually attract the attention of those very authorities they wished to avoid.

A reasonable way to check for jamming is the FAA ADS-B system. if a ADS-B outage exists in same area and time as client sees GPS failure Client is likely to be experiencing jamming as ADS-B utilizes onboard GPS receivers to report aircraft position using a transmitter at 1090MHz in real time instead of depending on ATC radar to trigger a transponder.

Link to the FAA ADS-B outage system below

https://sapt.faa.gov/outages.php?outageType=129001450&outageResolution=0.5

Content by Scott
Typos by Siri

On Jul 12, 2022, at 3:20 AM, Matthias Welwarsky via time-nuts time-nuts@lists.febo.com wrote: