Scanning computer radio receivers.

Scanning computer radio receivers.

Scanning computer radio receivers

The main tasks solved in the process of radio air monitoring are the search, detection and reception of the required radio signals. The characteristics of any radio monitoring complex that solves these problems largely depend on the parameters of the scanning radio receivers used in it. In fact, these devices are one of the most important functional elements of such a complex. In general, scanning radio receivers are characterized by the following indicators:

• the range of received frequencies:

• sensitivity;

• selectivity;

• scanning parameters (speed of tuning, viewing bands, etc.);

• the method or methods used, if any, to detect signals;

• the type of received radio signals;

• control efficiency and the possibilities of its automation;

• output parameters, such as the quality of signal reproduction at the receiver output, the presence of outputs at intermediate and low frequencies, the values ​​of the signal bandwidth at these frequencies, etc.;

• operational parameters (weight and size characteristics, power supply requirements, reliability, maintainability, ease of transportation, etc.).

The intended purpose of a scanning radio receiver as a means intended primarily for the rapid search of radio emission sources on the air predetermines the requirements for all its parameters. Models of scanning receivers existing on the domestic market usually meet the requirements for the range and scanning speed for searching for radio microphones or other radio emission sources that do not use the fast frequency tuning mode. At the same time, the ability to detect such radio microphones or the ability to monitor technically complex radio communication channels depend not only on the scanning parameters of the radio receiver, but also on the presence of other means in the complex that ensure the solution of such problems. Specialized software packages are currently increasingly used as such means. In these conditions, the ability of a scanning radio receiver to effectively operate as part of an automated radio monitoring complex controlled by a personal computer is of particular importance. For this purpose, a number of foreign and Russian manufacturing companies have developed so-called «computer» radio receivers, specially oriented to ensure effective interaction with a computer. Structurally, such receivers are made either in the form of boards built into the ISA slot of the computer, or in the form of separate modules connected to the computer via COM, LPT or PCMCIA ports. Thanks to this solution, a high speed of information exchange between the radio receiver and the computer is ensured, and the absence of additional external controls allows achieving small values ​​of the mass-dimensional parameters of the receiver.

The most widely represented radio receivers on the domestic market are those by Winradio Communications, which currently produces three types of scanning computer radio receivers: WR-1000, WR-1550 and WR-3150. Each receiver is available in two versions: with the index «i» in the model name — for installation in a computer and with the index «e» — as an external device. The first version is a computer board that is installed in the ISA slot of an IBM-compatible computer. The board size is the same for all internal radio receivers: 114x290x18 mm. Power consumption is 4 W. From the computer side, the radio receiver is identified as an external device on the ISA bus. Using jumpers on the receiver board, one of eight fixed addresses is set. Thus, it is possible to install up to eight radio receivers in one computer.

The WR-3150i-DSP radio receiver, which has a built-in ADSP-2105 digital signal processor, uses one interrupt and one direct memory access channel for operation, the numbers of which are also set using jumpers on the board. Based on receivers of this model, installed in an IBM-compatible industrial computer, the company has developed two multi-channel radio monitoring complexes: MS8006, which has six radio reception channels, and a three-channel MS-8003. The advantage of radio receiver models with an external design is the possibility of using them both in mobile and stationary versions under the control of computers of various types. However, in this case it is impossible to create multi-channel small-sized complexes based on one computer.

The dimensions of the receiver case with external design are 122x216x48 mm. Power is supplied from an external source via a network adapter. Interaction with the computer is carried out either via a standard serial port or via a PCMCIA port for use with laptops. To expand the capabilities for signal processing using other hardware or software, external models have an acoustic output on the rear panel. The technical characteristics of various models of computer radio scanners manufactured by Winradio Communications are given in Table 1.

Table 1. Technical characteristics of Winradio radio receivers

The ICOM company has developed a computer scanning radio receiver, designated IC-PCR1000. Its appearance together with the antenna included in the basic delivery set is shown in Fig. 1.

Fig. 1. Computer scanning radio receiver IC-PCR 1000

The receiver is connected to the computer via a standard serial port. The digital AFC system built into the receiver eliminates frequency drift in FM mode with bandwidths of 6 and 15 kHz and increases reception stability at frequencies above 1000 MHz. Reception of AM, FM and CW signals is possible with several bandwidths: AM — 2.8; 6; 15 and 50 kHz: FM — 6: 15; 50 and 230 kHz; CW- 2.8 and 6 kHz. The main technical characteristics of this radio receiver are given in Table 2.

Table 2. Technical characteristics of IC-PCR 1000 radio receivers

Currently, computer radio receivers are also created by Russian manufacturers. An example is the ARC-CT series receivers. This receiver has the following characteristics:

• frequency range 20-2020 MHz;

• dynamic range value of at least 70 dB;

• real-time tuning speed in 2 MHz steps under PC control of at least 140 MHz/s;

• power consumption up to 27 VA;

• the volume of the design is 5.6 dm ^ 3

The control of the rebuild and data transfer are carried out via one parallel port. It is possible to use a serial port (as an option) to solve additional problems.

The delivery sets of all the models described above include proprietary software control tools. The widest range of software (SW) is available for WiNRADi0 receivers. It should be noted that the software of these radio receivers does not differ significantly for internal and external models.

There are three types of software:

• basic software;

• additional software;

• software in accordance with the XRS specification.

The basic software is the main program for controlling the receiver and solves the following tasks: sets the tuning frequency and operating mode of the receiver, specifies scanning parameters and displays its results, and maintains a database of the operating results. The WiNRADiO program is designed to control the 1000 and 1550 series receivers, and the Spectrum Monitor program is designed for the 3150 series receivers (Fig. 2).

Fig. 2. Spectrum Monitor program: view of the radio receiver front panel displayed on the computer screen

As can be seen from Fig. 2, the user interface of these programs allows for control that imitates traditional control of a radio receiver from its keyboard. It should be noted that the Russian company «Unitek» is working on Russification of the basic software for various series of receivers. Fig. 3 shows an example of a visual display of the frequency range loading obtained using one of the Russified versions of the program for the 3150 series receivers.

Figure 3. Example of frequency range loading for WiHRADiO 3100 series receivers

Additional software is used to expand the receiver's functionality. The DIGITAL SUITE program allows you to analyze the time and frequency characteristics of a signal, process DTMF, CTCSS, analog facsimile, AX.25, ACARS signals, and also record audio signals in WAV file format to a hard disk. This program is integrated into the basic program and allows you to work with all types of WiNRADiO scanning radio receivers. A standard computer sound card is used to perform signal analysis and processing procedures.

Fig. 4. Spectrum of a two-position FM signal received by the DIGITAL SUITE program

Fig. 4 shows a variant of the spectrum representation of a two-position FM signal received by the DIGITAL SUITE program. The DATABASE program provides maintenance of a specialized database. It allows quite simply, during the process of reception, to accumulate and search for information about radio stations by frequency, by call sign, by coordinates and other data fields. The program includes an already formed database with information about more than 300,000 radio stations registered worldwide with data on their frequencies, countries of residence, and geographic coordinates.

In addition, there are special software modules designed to create radio monitoring systems for various purposes based on WiNRADiO receivers. An example is the Multichannel Spectrum Monitoring System software suite, which is used to control the operation of the MS-8003 and MS-8006 systems.

To attract independent developers, Winradio Communications has specially developed an open software specification XRS (extensible Radio Specification), allowing them to create their own application programs for WiNRADiO receivers. Such programs are integrated into the basic program and operate under its control with all types of radio receivers. The main advantages of creating software in accordance with the XRS specification are: fast writing of programs in high-level languages ​​such as C/C++ or Delphi, guaranteed compatibility with all subsequent versions of the basic software of WiNRADiO receivers, the ability to run several XRS programs simultaneously in parallel.

The interface of the PCR1000 control program for the IC-PCR1000 computer radio scanner (Fig. 5) is designed as several independent control windows for the main receiver modes, which can be placed anywhere on the computer screen.

Fig. 5. Interface of the PCR1000 program for the IC-PCR1000 computer radio scanner

In addition to implementing the basic receiver control functions, this program allows you to perform several scanning options, measure the relative signal level at the receiving frequency, as well as signals on adjacent channels in a maximum band of 200 kHz in real time, maintain a database of work results, decode DTMF and CTCSS signals during reception, and implement certain operations (for example, launching another program upon receiving a given sequence of DTMF codes).

High technical and operational characteristics of the described models of computer radio scanners have caused professional interest in them from independent developers of specialized software for solving various radio monitoring tasks. Thus, the creators of the set of programs for searching for radio transmitting means of unauthorized removal of audio and video information «Filin-98» included all models of WiNRADiO receivers and the IC-PCR1000 receiver in the list of supported radio receiving devices. A version of information presentation during the operation of this program is shown in Fig. 6.

Fig. 6. Interface of the search system «Filin-98»

Control of WiNRADiO radio receivers is also provided by the radio monitoring programs «KROT» and ARCON EXPERT. The latter program is also distinguished by the ability to support a large number of different scanning radio receivers, including the IC-PCR1000 computer radio scanner. One of the working windows of this program for controlling the WiNRADiO receiver is shown in Fig. 7.

Fig. 7. Working window of the ARCOH EXPERT program

For each type of scanning radio receiver, the ARCON EXPERT program has its own control panel, which takes into account all the technical capabilities of a specific model: range, types of received signals, scanning speed, signal detection method or methods, etc.

To summarize the above, we can draw the following conclusions:

1. The models of scanning computer receivers presented on the domestic market have fairly high technical characteristics as professional radio reception equipment.

2. The ability of computer radio scanners to effectively operate under the control of specialized software located on personal computers allows them to be used to build high-tech hardware and software systems for radio reception and radio monitoring with small weight and size parameters.

3. The number of different models of computer receivers and software tools for controlling them will be constantly expanding. This trend will be supported by both foreign and Russian manufacturers of the corresponding radio equipment and software.