The TCI Model 632 is a 5 meter sleeve monopole antenna suitable for use as a single-element receive-only antenna, or as part of a multi-element DF antenna array, featuring phase-matched balun and high signal sensitivity over the entire HF range.
The Model 632 antenna is available in either 632F (fixed) or 632D (deployable) configurations, with the 632F being provided with a concrete installation kit and the 632D being provided with a stake and guy kit. Both 632F and 632D versions of the antenna consist of a base section, a multi-element fiberglass radiator assembly, and a ground-wire kit. When used as part of a DF antenna array, the Model 632 is suitable for use with either interferometer or correlative interferometer HFDF systems.

When used with TCI interferometer HFDF systems, the Model 632 antennas can be deployed in a flexible array consisting of either 7 or 9 antennas deployed in “X,” “L,” or “T” configurations with baselines from 45 to over 90 meters.

When used with TCI correlative interferometer HFDF systems, the Model 632 antennas can be deployed in either a 12-element circularly disposed antenna arrays (CDAA) of 50 meter diameter or a 24 element CDAA of 100 meter diameter.

The 7235 consists of two identical receiving loop antennas arranged in a “crossed loop” configuration. Because loop antennas that operate at low frequencies tend to be very large, the 7235 uses an active magnetic loop design to minimise the physical size of the antenna. The 7235 contains two multi-turn loop antennas that are wound around high permeability ferrite rods to increase the effective area of the loop, and thereby increase the antenna sensitivity at low frequencies. The signal output of each loop is buffered by a high-dynamic-range active amplifier to improve the antenna noise figure. 

In addition to the two active loops, the 7235 system includes a low-profile active monopole antenna (Model 7031). The signal from this third antenna is used as a reference in the DF algorithm to eliminate the 180 degree angle of arrival ambiguity that is inherent in crossed loop DF antennas.

The 7235 is a compact, active antenna system used for direction finding of signals in the MF and HF bands. It is packaged in a small, but rugged, plastic housing that is suitable for fixed or mobile installations.

The 7235 is optimised over the range of 500 kHz to 20 MHz and operates over the frequency range of 300 kHz to 30 MHz. It is designed for DF systems using the Watson-Watt DF method. In this system, the azimuth angle of arrival of a vertically polarized signal is determined by measuring and comparing the phases and amplitudes of the received signal at the outputs of two loop antennas which are oriented at 90 degrees to each other.

The TCI Model 640D monitoring antenna offers broadband frequency range coverage from 500 MHz to 1300 MHz. The 640D does not require tuners, which eliminates the need for powered components within the antenna. The Model 640D covers the 500 to 1,300 MHz range using dual horizontal loops. A 50 ohm type N connector provides a secure connection and interface to RF receivers and analysers. The antenna assembly installs on to a building or tower structure via a standard 2” pipe mount.

The Model 640H monitoring antenna provides TCI’s 700-series spectrum monitoring systems vertical polarisation coverage from 20 MHz to 6 GHz, and horizontal polarisation coverage from 20 MHz to 3 GHz. (The 640H utilises integrated antenna elements to provide broadband coverage.) Reception of vertically-polarised signals between 200 MHz and 6 GHz is provided by a bicone antenna element; and a shunt-fed antenna element provides coverage from 20 MHz to 200 MHz. Reception of horizontally-polarised signals between 500 MHz and 3 GHz is provided by a slot antenna element. A loop antenna element provides coverage from 20 MHz to 500 MHz. Switching between antenna elements is performed automatically by TCI’s 700-series spectrum monitoring systems based on the frequency being scanned.