ERAU Prescott Observatory

Receiving Equipment

The observatory has two rf racks that provide antenna cable distribution, specialized radio astronomy receiving equipment as well as power supplies and test equipment. The racks also provide GPS receivers and clock distribution.

RF Rack 1

RF Rack 1 RF rack 1 provides the entrance cabling and signal patching for the Tower 1 antennas as well as the DART tiles. It contains two GPS receivers that are used to provide 10 MHz station clock. This clock signal is also sent to rf rack 2 for additional distribution.
  • Fluke 6062A Synthesized RF Signal Generator
  • HP 4396A Digitizing Oscilloscope
  • HP 4396A Network/Spectrum Analyzer
  • Lavolta BPS-305 variable DC power supply


The rack also contains the three Ettus USRP X-300 receivers and associated GPS integrated clock and distribution. This is the receiving section of the DART telescope

There is also a dual Airspy receiver system located in the rack along with power supplies for DART and Tower 1.

RF Rack 1 Bottom
Various power supplies for the telescopes & receivers associated with rf rack 1:

RF Rack 2

RF Rack 2 RF rack 2 provides the entrance cabling and signal patching for the Tower 2 antennas as well as the rest of the various radio telescopes not associated with rf rack 1. Equipment located in rf rack 1 include the following:
  • Station Clock distribution
  • Spectra Cyber 406.7 MHz Radio telescope receiver
  • Spectra Cyber II,
  • 1420 MHz Hydrogen Line Spectrometer
  • Long Wavelength Receiver
  • Signal patch and test ERRO
  • Hydrogen Line receiver
  • LoRAX 02 Airspy receiver
  • Callisto Spectrometer
  • Ettus USRP2 Universal Software Radio Peripheral
  • Three Ettus B210 USRP receivers from the original DART receiver configuration
  • Antenna control panel for the 4-meter dish
  • Spare antenna control panel
RF Rack 2 Bottom
Various power supplies for
the telescopes & receivers associated with rf rack 2:

Receiving Equipment Detail

Spectra Cyber 406.7 MHz Radio Telescope

Spectra Cyber Receiver

A low-noise, down converter centered in the middle of the allocated radio astronomy frequency bands of 406.7. Both frequencies have been noted in the area of Pulsar detection and continuum radio astronomy.

Spectra Cyber 1420 MHz Hydrogen Line Spectrometer

Spectra Cyber Receiver

This triple conversion spectrometer covers the rest frequency of Hydrogen +/- 2 MHz. In addition, the computer controlled display shows both spectral and continuum channels.

Callisto Spectrometer

Callisto Sepectrometer
The CALLISTO spectrometer is a programmable heterodyne receiver built in the framework of IHY2007 and ISWI by former Radio and Plasma Physics Group (PI Christian Monstein) at ETH Zurich, Switzerland. The main applications are observation of solar radio bursts and rfi-monitoring for astronomical science, education and outreach. The instrument natively operates between 45 and 870 MHz using a modern, commercially available broadband cable-TV tuner CD1316 having a frequency resolution of 62.5 KHz. The data obtained from CALLISTO are FIT-files with up to 400 frequencies per sweep.

Ettus USRP2 Universal Software Defined Radio Peripheral

Attus USRP2  RecieverThe Universal Software Radio Peripheral (USRP) allows the observatory to rapidly design and implement flexible software radio astronomy systems. The use of LINUX GNU Radio, which is a software radio and signal processing package allows for modular software construction of specialized receivers.

In the USRP, high sample-rate processing takes place in the field programmable gate array (FPGA), while lower sample-rate processing happens in the host computer. The two onboard digital down-converters (DDCs) mix, filter, and decimate (from 64 MS/s) incoming signals in the FPGA. Two digital up-converters (DUCs) interpolate baseband signals to 128 MS/s before translating them to the selected output frequency. The DDCs and DUCs combined with the high sample rates also greatly simplify analog filtering requirements.

We have a LFTX daughter board which allows signals from dc to 30 MHz to be captured directly.

We also have a TVRX daughter board which covers the range of 50 MHz to 860 MHz with a 6 MHz wide block down converter.

Ettus USRP – B210 Software Defined Radio

Ettus B210 ReceiverThe USRP B210 hardware covers RF frequencies from 70MHz to 6 GHz, has a Spartan6 FPGA, and USB 3.0 connectivity. This platform enables experimentation with a wide range of signals including FM and TV broadcast, cellular, Wi - Fi, and more. The USRP B210 extends the capabilities of the B200 by offering a total of two receive and two transmit channels, incorporates a larger FPGA, GPIO, and includes an external power supply. Both use an Analog Devices RFIC to deliver a cost-effective RF experimentation platform, and can stream up to 56 MHz of instantaneous bandwidth over a high-bandwidth USB 3.0 bus on select USB 3.0 chipsets (with backward compatibly to USB 2.0). Because the B200 and B210 are enabled with our USRP Hardware Driver™ (UHD), users can develop their applications and seamlessly port their designs to high-performance or embedded USRPs such as the USRP X310 or USRP E310. UHD is an open-source, cross-platform driver that can run on Windows, Linux, and MacOS. It provides a common API, which is used by several software frameworks, such as GNU Radio.

Sudden Ionospheric Monitor (SID)

SID Receiver
The monitors detect changes to the Earth’s ionosphere caused by solar flares and other disturbances. Our space weather monitor measure the effects on Earth of solar flares by tracking changes in very low frequency (VLF) radio transmissions as they bounce off Earth’s ionosphere. The VLF radio waves come from transmitters set up by various nations to communicate with their submarines. Signal strength of these VLF waves changes as the Sun affects Earth’s ionosphere, adds ionization, and thus alters where the waves bounce. Our monitors track these changes in signal strength. For more information, click here.

Radio JOVE Receiver

Radio Jove ReceiverThe Radio JOVE is a NASA designed narrowband noise receiver designed for operation at 20 MHz +/- 150 KHz. The receiver does not have any demodulation or automatic gain control to allow it to pick up very low intensity noise bursts from Jupiter. It is also a very good receiver for monitoring solar storm activity. The receiver has an audio output that allows operation of special software to capture, record and archive data runs. The observatory also has a calibrator noise source which is used to perform calibration runs before and after each data run. For more information, click here.