SparkPNT RTK mosaic-X5 Antenna 0.0mA

GPS/GNSS
1

Hello,

I have pair of SparkPNT RTK Mosaic-X5 units that have served me well until yesterday. After about a year, the base unit stopped receiving satellite signals (the other unit using the same antenna path is working fine).

I ran diagnostics and it looks like the PESD0402-140 might have failed (it is showing Ant#0: 4.507V 0.0mA) when connected).

Is there a way to get this repaired? I’d do it myself; but the eyes and steady hands aren’t what they used to be.

Thanks,

Thomas

2

Hi Thomas (@coder_6912 ),

Sadly, we have seen a small number of X5 antenna power failures with the same symptoms as yours… It’s unlikely to be the PESD0402 causing the issue.

Things to try:

If you have a digital multimeter, please: power the unit up, disconnect the antenna, and measure the DC voltage at the SMA antenna connector, between the center pin (+ve) and the outer thread (0V). I suspect you will see 0V, but please confirm.

If you have a passive GNSS antenna, please try attaching that and check if any GNSS signals are received. It needs to be a passive antenna without an internal amplifier. If you see signals, it proves the RF path is still working and only the antenna power has failed.

Let us know how it goes. Thank you.

Best wishes,
Paul

3

Hi Paul,

+4.1VDC tip to ring. Both systems are running through a high-end antenna splitter (GPS Source IRMS1X16 where both are connected to a resistive 200ohm load. Strangely enough, I am having trouble finding a truly passive GPS antenna.

Thomas

4

Hi Thomas,

OK. Thank you. Let me walk this through a little more…

Your IRMS116 is providing power to the active antenna from its built-in power supply. “The DC blocked outputs feature a 200 Ohm DC resistive load to ground simulating an antenna DC current draw for any receiver connected to those ports.”. So each of the 16 antenna outputs is DC-blocked, preventing the GNSSes from providing power to the antenna. Each GNSS should see a 200 Ohm load on its antenna port and so should be delivering around 20mA.

I thought originally that the active antenna power circuit inside the X5 had probably failed. Like I said, we have seen a small number of those failures previously. But the 4.1VDC you measured at the SMA connector suggests that the X5’s antenna power circuit may be OK, and that the failure is on the X5 RF path. That’s odd… I don’t think I’ve seen a similar RF failure previously. Maybe the PESD0402 is the cause after all?

The “Ant#0: 4.507V 0.0mA” is also puzzling. If the SMA connector has a DC voltage on it, the X5 should be measuring a draw of around 20mA when the 200 ohm load is present.

All I can suggest is that we get you started with a Return for further analysis. Please start a return here: Return Policy - SparkFun Electronics . Please include a link to this conversation, and please also include the note “Returned for investigation of possible antenna RF path fault”.

Thank you,
Paul

5

Hi Paul,

I purchased this unit used; can I still RMA it?

Thanks,

Thomas

6

Ah. That’s more tricky. I will ask one of my colleagues to contact you directly.

Best,
Paul