Antennas interference

Just 1/4 wave wires will do, ideally you would add 1/4 wave radials as well, but that may not always be too practical.

The GPS can benfit from using a 3/4 wave wire, it does improve reception.

If you want to use stiff wire, that is self supporting, like you would on a balloon tracker, then Ernie Ball Custom Gauge 9 or 13 guitar wire is a popular choice.

For the LoRa antenna I mostly use PTFE wire, its very tough and less likley to break.

Thickness is not that important.

The limitations on the GPS relate to the GPS as sold not what particular GPS constellation they are receiving. It would be peverse to have speed\height limitations if a simple config command could bypass them.

@srnet
ok, ill use these wires, but what about impedance? I know that that depends on the radials but what about the PCB I calculated that to gen 50 ohm I would have to have the track 3mm thick which is a lot even the part spacing isn't big enough for 3mm, for example, the GPS Low Noise OpAmp has 0.5mm trace pads.

And what about the capacitor and HF Inductor that are between the antenna and Low Noise OpAmp?

thanks for the help

If the tracks from antenna to device are real short, then matching the impedance of the track is not so significant. Take a look on the LoRa modules themselves, do you see 3mm tracks anywhere ?

Never used a GPS with a 'Low Noise OpAmp', I just attach the antenna wire direct to the antenna input. I do sometimes use a self resonating inductor between antenna input and ground, to protect the GPS input from static damage which is an issue with the Ublox GPS. The Quectels dont seem to suffer the same issue.

There comes a time when you just got to try stuff.

@srnet

Oh, that's interesting thanks for the help.
I was following the schematic from the datasheet of the GPS (page 14 - Passive antenna solutions): http://www.icofchina.com/d/file/xiazai/2016-12-05/b5c57074f4b1fcc62ba8c7868548d18a.pdf

so should I follow the schematic on page 13 - (Active antenna solution) or just connect the antenna to the module?

Thanks.

Whatever, like I said I have never played with adding LNAs to GPSs, so I dont know if that particular GPS would benefit from one or not.

Ok, ill leave it as it is I can always connect it straight. ill test it if it helps and sends you the results if you want.

Thanks for all the help