High power consumption with flat sticker GPS antenna - T-404M

In pursuit of a more compact design, we brought in a sample of this antenna:

It works, but the GPS gets hot and the board uses 400 mA more than it does with a ceramic patch antenna. I expect that this is because the GPS is providing a voltage that would normally go to driving the LNA in a typical patch antenna. Is this correct? Is there a way to turn off this voltage so we can use a sticker antenna?

It looks like it should be possible, but I did not test it. The active antenna power supply is controlled by the LNA_EN pin on the u-blox GNSS. It defaults to on.

It can be turned off in software from the GNSS by issuing a UBX_CLASS_ANT message. This can be done by calling the setAntanna() method in the uboxGPS class, which is available in Tracker Edge. And that is the spelling of the method.

The value appears to be this from the NEO-M8 datasheet. You want to set pinSwitch to 0, so pass a value of 0x8000.

Incidentially, you cannot enable short or open detection because it requires different hardware on the antenna circuit, and a special antenna that supports detection.

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Thank you! That resolved the issue.

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