[time-nuts] Re: GPS failed

[David G. McGaw]

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 with an Iridium ground station (just above the GPS L1 frequency) 
for scientific balloon data that had a new cell installation placed 
nearby.  We had (and thankfully were able to) have the cell base station 
shut down while we were flying.

73,

David N1HAC

On 7/11/22 9:27 AM, paul swed via time-nuts wrote:
> 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 AM skipp Isaham via time-nuts <
> time-nuts at 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
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