Is it always necessary to connect antenna to RTK mosaic-X5?

GPS/GNSS SparkPNT / Consumer Products
1

I just recently purchased a SparkFun RTK mosaic-X5. I have seen statements that powering on similar products without a GNSS antenna connected will harm the unit.

Yesterday I went through the Septentrio hardware and reference manuals for the mosaic-X5 and found nothing to support that.

Situations where it would be convenient to not have the GNSS antenna connected would be brief periods for configuration and firmware updates.

Anyone know?

2

On that device it simply becomes an open circuit https://docs.sparkfun.com/SparkFun_RTK_mosaic-X5/assets/board_files/schematic.pdf - you won’t get any GNSS/fix but powering it without an antenna won’t harm it

3

That’s the way I read it as well. All the protection mentioned in the Septentrio documentation was for overcurrent, not for no current.

Thanks!

4

You are probably talking about an ArduSimple board? I have one and they say add the antenna to prevent overheating of other components on the board. In general GNSS modules can be powered without an antenna connected. Haven’t actually tried it with the ArduSimple board, but with others, no problem.

5

The warning I saw very likely was in reference to an ArduSimple product, thanks for reminding me!

6

Hi @IC_Rhodes ,

You can operate the SparkFun RTK mosaic-X5 quite safely with no antenna attached.

But, please be aware that the mosaic-X5 has a feature where if you reset the X5 more than four times with no antenna attached, it enters a special “Ready for SUF download” mode. This prevents the GNSS COM ports from being used normally. Full details are available at:

https://customersupport.septentrio.com/s/article/How-to-troubleshoot-receiver-reporting-Ready-for-SUF-download

Note that power-cycling the mosaic-X5 with no antenna attached doesn’t cause it to enter this mode. You need to pull the internal GNSS Reset (MOSAIC RST) signal low five times with the power on throughout. Only then will it enter this mode.

This can be useful. If you have set User Credentials and then forgotten the password, effectively locking yourself out of the GNSS, you can use this feature to: force an SUF upgrade, upgrade to 4.15.1, do a FactoryReset, then downgrade to (e.g.) 4.14.10.1 if needed.

I hope this helps,
Paul