Re: Issues with E320 - AD9361 temperature sensor readings

On 2025-12-09 12:48, Indrajit Bhattacharyya wrote:

Hi Marcus,

 

Sorry for writing to you directly as my query on the gnuradio discuss list has not come up with any response in the last 2-3 weeks.

 

Also, apologies for posting the above on the gnuradio list as the usrp-users list is down for some reason.

 

I needed some help identifying a rather odd issue I am facing with some new E320s we acquired as the older E310s are now not recommended for new designs.

 

When reading the temperature from the AD9361 I am consistently getting very high readings, confirmed with direct chip surface temperature measurements – typically of the order of 60-70C for Rx only streams, and 80-90C for streams with both Tx and Rx.

 

My requirements are very humble – the FPGA is not used at all – all data is processed on the main CPU.

 

Typical Sample rates are between 1.92 MHz to 30.72 MHz for Rx streams, and Tx is set to 30 kHz.

 

The Tx transmits only a CW.

 

When comparing with the old E310, the temperature difference is about 30C, with the same underlying code.

 

Any idea why this is happening or what I am doing wrong.

 

FYI, stopping the streams actually causes the temperature on the AD9361 to rise, which is very weird.

 

The sensor values are read using: usrp.get_sensor(i).to_real() – we only need the rssi and ad9361_temp sensors.

 

And the stream start / stop is effected using: self.uhd_usrp_source_0.stop(), self.uhd_usrp_source_0.start()

 

Sample rates on the receive are changed using:

        self.uhd_usrp_source_0.stop()

        self.uhd_usrp_source_0.set_samp_rate(self.rxSamp_rate)

        self.uhd_usrp_source_0.set_bandwidth((self.rxSamp_rate*2), 0)

        self.uhd_usrp_source_0.set_bandwidth((self.rxSamp_rate*2), 1)

        time.sleep(0.5)

        self.uhd_usrp_source_0.start()

 

Fundamentally, the system is used to compute the DOA using either high power noise sources or CW signals from a TE21 coupler inside the feed of an antenna.

 

UHD: 4.8.0.0

Python: 3.12.0

Windows: IOT

 

Default configuration of USRP:

 

MCR: 30.72 MHz or 16 MHz

Rx Frequency: 2G – 3G

Tx Frequency: 5G-5.5G

Tx Gain setting: 75 – 80 dB (~10 dBm output)

Rx Gain: AGC

 

All streams are carried over the 10G SFP modules. No packet losses.

 

Any help or insight would be greatly appreciated.

 

Thanks,

 

Indrajit.

 

I don't have an E320 myself, but I've reached out to my colleagues to see what "normal" is for these devices.  90C seems quite excessive.  Is this happening on more than one
  unit?