ADU-11e

about to be finalized May 2025

The ADU-11e (Analog Digital Unit) is a HF logger with 8 channels and 131 kHz max. continuous sample rate on 6 channels, 64 kHz on 8 channels and with 1024 Hz lowest native sample rate. Online filtering with 8x, 32x.
The system has a single mainboard with all channels integrated and soldered GPS (GPS, Galileo, Glonass, BeiDou). The CPU is an ARM quad core 64bit.

One of the design aims is to keep the system small and light weight for airborne applications (250 g board and 250 g connectors).
The channel configuration is 2xE and 6xH.
3 H channels can be connected to a SHFT-02e or SHFT-03e and the other 3 H channels to a FGS-04e type fluxgate (airborne)
GPS data will be written @0.1Hz for control.
For ground based recordings you connect coils like MFS-06e, MFS-07e or MFS-12e and an electric field.
You can also connect a SHFT-03e while recording with the default coils; for example acquiring dedicated AMT data with this specialized sensor
For extended LF recordings with 6 magnetic fields, use the ADU-12e. However the combination of ADU-10e and ADU-11e is more flexible and has the same price.
While doing LF measurement with the ADU-10e and using the 10e as remote reference station, you can use the ADU-11e for the HF/LF data.

Technical Data

Tech. Data	Specs.
Frequency range	4096s to 64 kHz
Number of channels	8
Native sample rates of A/D converter	131, 64 … 1 kHz 512 … 32 Hz with integrated filter (lower sampling rates by off-line digital filtering)
A/D conversion	HF/LF: 24 Bit (data rate max. 131 ksamples/sec)
Input resistance	>10 MΩ E, >22 kΩ H
Nominal input voltage range (@ gain 1)	E: +/- 2.5 V and H: +/-10 V
System computer	24 bit low-power embedded controller with Linux operating system
Storage media	64 GByte SD card[1] (4 TB on external USB disk with ext4), USB-pen-drive or other external USB mass storage device
Test facilities	Automatic on power up self-test of all important system functions including sensors and display of result on the instrument. Automatic creation of log-file
Input noise	E @gain1: 70 nV/√Hz; H @gain1: 300 nV/√Hz E @gain64: 7 nV/√Hz; H @gain64: 30 nV/√Hz
Calibration	automatic calibration
Network connection	100 MBit Ethernet with RJ45 connector, WiFi module
Synchronization	72 channels GNSS synchronized clock, accuracy +/-30ns rms accuracy of 1pps signal, station position is also determined and stored (GPS, Galileo, Glonass, BeiDou )
Standard connectors for 8 channel system	1 x Network RJ45 100 MBit ruggedized socket(s)
	3 x Magnetometer 10-pole Socket ODU G32K0C-P10QJ00-0000
	4 x E-field input terminal 6-pole Soket ODU G32K0C-P06QP00-0000
	1 x Multi-Purpose for fluxgate 12 pole Socket ODU G32K0C-P12QF00-0000
	1 x GND terminal
	2 x input 12 V battery, protected against reverse polarity Socket ODU G32K0C-P02LTS0-0000
	1 x ext. satellite antenna SMA-Type socket
	1 x ext. WiFi antenna SMA-Type socket
	1 x USB2.0 Type A
Case	ruggedized, water-resistant case
Weight	appr. 4.8 kg
External dimensions	WxHxD 33 cm x 12cm x 25 cm
Power Input	9V … 15V DC
Power consumption	4 W[2]
Operating temperature range	-30°C to + 60°C

Cable Plug	Connector (plug)
E-field	S22K0C-P06MPH0-400S ODU MiniSnap Series K
H-field	S22K0C-P10MJG0-700S ODU MiniSnap Series K
Multi-Purpose	S12K0C-P12MFG0-7000 ODU MiniSnap Series K
Battery	S22K0C-P02MTS0-650S ODU MiniSnap Series K

ADU Socket	Connector (socket)
E-field	G32K0C-P06QP00-0000
H-field	G32K0C-P10QJ00-0000
Multi-Purpose	G32K0C-P12QF00-0000
Battery	G32K0C-P02LTS0-0000

~ 64 Hz yaw, pitch, roll sampling for SHFT-02e, SHFT-03e and FGS-04e in preparation for airborne applications
simultaneous recording of AMT & MT with dedicated sensors
continuous streaming of atss data for remote logging

The systems writes standard ats files as well as streamed double data atss (Matlab, Python/Julia NumPy array compatible with JSON data header)

You can use syncthing, rsync and WebDAV to transfer data to your office.

24 bit is back

The ADU-11e is using a 24 bit A/D converter.
When we look at the drift of the electric field, we see that the drift (especially the first day) is 100 times greater as the signal.
And sure, a 32 bit converter digitalizes that without range problems.
But there is no 32 bit A/D converter available for sampling rates above 4 kHz.
But the 24 bit A/D converter of the ADU-11e with its integrated amplifiers records easily periods down to 4096 s.
And: with the MFS-12e you want to take the benefit of simultaneous sampling of AMT and MT data.
So, that is like in Goethe’s Faust or Heisenberg’s uncertainty principle:
You can have it all, but not at the same time.
Most of our users want a smooth resistivity and phase curve from 10 kHz down to 100s or 1000s.

For most MT/AMT applications, use the ADU-11e when a fluxgate is NOT needed.
Only for dedicated long term LF measurements, use the ADU-10e with a power consumption of 2.5W

LMT

Some may miss the LMT (Low Magnetotelluric) option with 32 bit digitization range, especially for fluxgates.
Well, the ADU-11e is 50% compared to the old ADU-08. You have the option to use the ADU-10e for LF data and the ADU-11e for HF data.
The great benefit is that you can use both systems in parallel, leave the ADU-10e at the LF site and make multiple HF measurements with the ADU-11e.
In this combination the MFS-12e is the perfect sensor for the ADU-11e and gives more than a full decade of overlapping data with the fluxgate!
That is extremely efficient.

modern profile measurement setup

Environmental

In case the item is no longer needed, please dispose it according to the local regulations for electronic waste.
Dispose items only at qualified places, not in your household waste.