My SparkFun RTK Postcard never acquires satellites. Firmware v3.0, Rover mode, all constellations enabled, helical antenna (GPS-23847) inspected and reseated, tested outdoors several minutes. The serial console shows SIV: 0, GNSS State: No Fix, and “No GNSS date/time available for system RTC” continuously. Configuration is not the cause. SparkFun Customer Support (ticket reply 2026-09-17) directed me here for troubleshooting before a replacement can be issued. Please advise on next steps or RMA.
When testing outdoors do you have a clear/unobstructed view of the sky?
What are the LEDs looking like when powered? It might help to share a photo of the setup as well
Welcome @randallr ! Do you have access to a digital multimeter? Can you verify that you see ~3.3V between the center pin and the shroud:
Fabulous! Thank you. That answers my question: the antenna is getting power.
Next up: Do you have access to a different antenna? Any GPS antenna would work (doesn’t have to be a fancy L1/L2 antenna). This will tell us if the helical is the issue or if the Postcard itself has a problem. If you do not have another antenna, or if you want us to simply give everything a thorough once over, we can start you on the RMA process here.
That link gives me a 503.
The Web server had a brief stint of hiccups, it should be working now 
@randallr - Oddly, it’s down for me as well. Sorry about that. I will DM you an RMA.
Is there a good way to diagnose the antenna separately from other components without another antenna to try? I.e. make sure the antenna is good/bad in isolation.
Without connecting it to a spectrum analyzer or another piece of GNSS equipment, no, I don’t have a good way to troubleshoot a bare antenna. If you have another GNSS antenna, then we could hook it to the Postcard. That would quickly tell us if it’s the Postcard or the antenna at fault.
Even a super cheap L1 GPS, or GNSS, only antenna would suffices as a quick counter check.
One can also connect an active antenna to a bench supply, at 3.3V (w/50mA current limit), and observe the reported current draw. Most modern example one might expect perhaps 10-15mA draw, some of the high gain perhaps into the 20’s or 30’s of mA. Or see if you’ve got an open or short condition.
A spectrum analyzer might not help as the GNSS signals are buried in the noise floor, pseudo random code signal, and each satellite with a doppler shift as in motion wrt antenna. You might see the band over which the LNA is operating, but without a SAW filter than might span DC to a couple of GHz.
My Postcards typically show SIV:0. However, I do get RTK Fix and when I look at the output in a custom app I have anywhere from 29-33 satelites.
I would enable your RTK State in your messages if you haven’t already. That will give you more info.