Can ST Reader read when UHF Antenna and UHF Tag between Woods?

[SS1]

Hello,

I am working with ST25RU3993 Reader and kit's Antenna.

Initially, the Reader was able to detect different Tags using different Antennas. Then, by placing the antenna below a wood surface and tags above the wood surface, the ST UHF Reader was not able to detect any Tags. Later, even at normal conditions (without wood and placing all in a plain surface without any interruption) the Reader did not read any Tags, which worked fine before the above told setup made. I feel the Reader is damaged but not Antenna or Tag. Even after updating ST Reader with new ST Firmware Version 2 and ST GUI Version 2, the Reader did not read any Tags. Byconnecting ST Reader with ST GUI, the LEDs (MCU OK, PLL OK, OSC OK, D16/17, EXT_PA, Tuning, Tuned, RF ON) Turns ON but there is NO TAG RESPONSE. Booting or Reseting or Antenna Tuning neither did not work.

I would like to know where the problem is. Is it with ST Reader, which can not read between Woods?

Kindly help with the same.

Thanks.

[Bart Herse]

Hi,

typically wood shouldn't be big problem unless the wood contains a lot of moisture.

What kind of wooden surface is it that you are experimenting with?

How did you confirm that the problem that you are currently facing is not due to a damaged tag?

Can you still read your tag with another reader?

Was the RF power turned ON without an antenna attached or maybe have switched to an antenna port where no antenna was connected to?

In case you have a means to test the output power (e.g. spectrum analyzer) I would check if you have reasonable output power (typ. 28 dBm)

You could also try to switch to the internal PA in the reader settings of the GUI and see if you can read your tag.

Cheers,

B

[SS1]

Hi,

Thanks for the reply.

The type of wood used is "Multiplex Platte - Brich wood", used without Moisture content.

The Reader did not read any Tags (even new Tags) with different type of Antenna, so concluded that Reader might be a Problem. Unfortunately, I did not have another Reader to test but I am sure that Tag or Antenna is not damaged. The RF power turned ON wit/without Antenna connected and checked with different Antenna Port with different Antenna and Tag but still it did not detect.

Now, I tried to switch to internal PA in the reader settings of the GUI and noticed that Reader "can read" all tags and also using different Antenna Port with different Antennas. Noticed that the Reader did not read when it is in external PA.

Kindly help by saying the solution to proceed with.

Thanks.

[Bart Herse]

Hi,

Please note that the reader should never be turned ON without an antenna connected to the active antenna port - it might damage the reader.

Could you check the voltage on the J21 when switched to external PA and when CW (diagnosis tab in reader settings) is turned ON?

Also check if R3 is in place.

Is there any visible damage at U2 or U11?

please PM me your email address and a close-up picture of your reader with the shield cover removed and we can discuss further steps.

Cheers,

B

[SS1]

Hi,

I checked the voltage on the J21 when switched to external PA and when CW (diagnosis tab in reader settings) is turned ON, it shows 0.098mv DC. Also R3 is in place and no visible damage to U2 or U11.

kindly help me with the same

thanks.

[Bart Herse · Accepted solution]

Hi,

the external PA supply seems to be damaged as the typical supply voltage is 4.1.

Desolder R3 and check on Pin 2 of J21 if the 4.1 V can be seen then.

Cheers,

B

[SS1]

Hi,

the external power supply gives 4.1V without CW (diagnosis tab in reader settings) is turned ON. Does this also mean external power supply is damaged? (without desoldering R3 resistor)

kindly help me with the same

thanks.