[time-nuts] GNSS Antennas (was: Rooftop antenna and splitter)

[Bob kb8tq]

Hi

I get the impression that they do indeed run things up a band at a time and 
pretty much ignore what is in-between. Again, we’re talking about the “affordable”
end of the new antenna range here and not the price is no object part of the 
market.

Bob

> On Jan 31, 2019, at 12:45 PM, Attila Kinali <attila at kinali.ch> wrote:
> 
> On Thu, 31 Jan 2019 08:51:46 -0500
> Bob kb8tq <kb8tq at n1k.org> wrote:
> 
>> Looking at network analyzer sweeps, it becomes pretty apparent that whatever 
>> combination of things are involved, they only work inside each of the target sub-bands.
>> Once you get to the edge, it all falls apart. It comes back together once you get to
>> the edge of the next sub-band. Some of that is intentional filtering so sorting it out 
>> that way … not so much. 
> 
> Transmission line phase shifters are pretty narrow band.
> Getting them to 5% bandwidth with reasonable phase and
> amplitude stability is already not straight forward. But
> for a combined GPS/Galileo/Glonass L1/L2/L5 antenna,
> a bandwidth of over 30% would be needed. Not an easy task
> at all. Making them work for a few select bands is a lot
> easier, if still a bit non-standard. At least EM simulation
> tools help a lot with that.
> 
> 			Attila Kinali
> 
> -- 
> It is upon moral qualities that a society is ultimately founded. All 
> the prosperity and technological sophistication in the world is of no 
> use without that foundation.
>                 -- Miss Matheson, The Diamond Age, Neal Stephenson
> 
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