Radio Monitoring

Using the analogue AR5000 receiver for radio observations

With the advent of SDRs, monitoring with analogue radios is more of a historical case. The use of an AOR AR5000 communications receiver for monitoring purposes is described here. The built in RS-232 interface allowed to control the receiver and to read the level of the automatic gain control (agc) representing the received RF-power. The applied control software was written in PASCAL and can be downloaded freely.

AR5000 - Technical aspects

Here I will describe some technical specifications of the AR5000. This is necessary to understand the results of a monitoring session.

Recording of rf-signals will be influenced by a couple of factors: The characteristic curve of the automatic gain control (AGC) significantly affects ratio of observed data and must be linear. The selected if-bandwidth determines the frequency resolution and thereby the sharpness and height of the logged rf-signals. Finally, the course of the spectral sensitivity over the received radio frequencies must be flat in order to avoid a shift in the received signal quantities at different frequencies. Read more:

Software AR5000RA

The software AR5000RA provides a set of functions to control the receiver as described in the AR5000 operation manual. Subsequent you will find information about the general operation of the program. Especially the monitoring mode needs some detailed presentation of its features. Read more:

This mind map informs about requirements, installation and settings of the software. It actually runs under Windows 7 but no more under Windows 10:

Examples of Monitoring

I used the AR5000 together with the monitoring function of the AR5000RA-software for studying ionospheric radio wave propagation and direction finding.

The active antenna DX-500 from RF-Systems and a custom made broad band
magnetic loop antenna of 0.6 m diameter were employed in these studies.

Map from: Courtesy of the University of Texas Libraries, The University of Texas at Austin.