Sent from my Phone
> On 13 Jul 2022, at 02:34, Bob kb8tq via time-nuts
> wrote:
>
> Hi
>
> The “typical” Symmetricom cone shaped GPS antennas are targeted at
> cell phone tower applications. Being mounted on the same structure
> as multiple cell transmitters puts them in a significant RF
Thanks Bob.
I believe this is what I have (I would need to climb up on the roof to double
check the part number (assuming the label is still legible..))
https://www.microsemi.com/document-portal/doc_view/133381-58532a-datasheet
Best regards
Mark Spencer
Sent from
Hi
The “typical” Symmetricom cone shaped GPS antennas are targeted at
cell phone tower applications. Being mounted on the same structure
as multiple cell transmitters puts them in a significant RF environment.
They have a *lot* of filtering built into the antenna to try to prevent overload
For what it is worth...
I have a commercial grade ( Symmetricom ?) GPS antenna on the roof of my home.
I don't recall ever having any issues with GPS reception despite having / had
various other transmit / receive antennas on the roof for various frequencies
from 1.8 MHz thru 1.3 GHz. Power
> I'd like to get some opinions and war stories regarding GPS reliability at
> high RF level and elevation locations.
At last count I’ve got ten GPS/GNSS active antennas scattered around the
house (I have a very understanding spousal unit), including one in the
kitchen skylight and one
Hi Matthias,
There has been interference reported and resolved between 23cm and Galileo,
which have signals in the 23cm band.
/Björn
Sent from my Phone
> On 12 Jul 2022, at 09:20, Matthias Welwarsky via time-nuts
> wrote:
>
> Hi,
>
> if you're worried about in-band interference, the
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’
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
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,
Andy Talbot said:
> I also heard a case of a GPS antenna going unstable, oscillating and taking
> out most of the boats in a marina. The Radio Communications Agency (as our
> enforcement body was then, before it became Ofcom) had to be called out to
> identify the problem.
There was an
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
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
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
>
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,
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
The u-blox SAW filtering is great. We've carried out various RF
measurements with +40 dBm EIRP at 2.53 and 3.75 GHz with some u-blox
ANN-MB within <2m of the Tx antennas. While we haven't conducted
in-depth comparisons with a superior ground-truth, my current conclusion
is that the u-blox RTK
With the new 5G hardware, we are seeing all manner of new interference,
some of it quite broad-band. A good antenna with sharp SAW filter may
help, but not if the emmisions are in-band. Besides broad-band, there
also can be 2nd harmonic emissions that cause interference. We had this
problem
There is a 3G/4G Supplementary Downlink allocation at 1492MHz in some
countries. Close enough to cause problems.
Andy
www.g4jnt.com
On Mon, 11 Jul 2022 at 14:40, paul swed via time-nuts <
time-nuts@lists.febo.com> wrote:
> Skipp
> I am aware at least in the US that there is the possibility
I have had one, and possibly two, low cost active antennas go unstable and
start oscillating. These are the magnetic car mount type with a ceramic
patch antenna. The ceramic patch has quite a high Q and determines the
frequency the unstable RF front end takes off at - which is obviously at
Skipp
I am aware at least in the US that there is the possibility of 5G
interference along with newer possible bands that 5G can use. I have read
several articles in a publication called GNSS.
Thats why I am using wwvb at 60 KHz. Humor intended.
Regards
Paul
WB8TSL
On Mon, Jul 11, 2022 at 8:49
On 7/10/22 4:19 PM, 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 Sun, July 10, 2022 6:19 pm, skipp Isaham via time-nuts wrote:
> 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
Hi Skipp -- there is a lot of info about interference mitigation in the u-blox
integration manual for the ZED--F9T (available under the docs at
https://www.u-blox.com/en/product/zed-f9t-module). It might give you some
clues, and I think might also point to another u-blox app note on the topic.
Hey Skipp!
A couple of thoughts…
Why do you need an amplified antenna in a high and open spot, unless the coax
run is longer than about 40’?
Is it practical to move one of the existing antennas away from the current
location as a test to see if it’s a failure vs overload? Assuming it is
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