Remote Multi-Channel Marine Base Station for the Barbados Coast Guard using a combination of Tait T800II and the TM8000 equipment

The Tait T800II was a logical choice for this system. These modules can be programmed to operate on several channels which can be selected by the Tait T803 remote control unit.

Using the traditional 4-wire leased lines from Fort Willoughby, the Coast Guard headquarters, to the repeater site was not an option, simply as there were no land lines in its vicinity.  Installing a full duplex radio link we estimated would have increased the cost by five times!

We used two of the very versatile Tait TM8000 series radios to link the base to a remote repeater site. These radios provide a link for both the channel select tones as well as providing a voice link to ships around Barbados.

At the Coast Guard HQ at Fort Willoughby we used a UHF Tait T8250. Here we interfaced this to a Midian Electronics TRE2 remote tone encoder. The Midian TRE2 is a simple unit that can send (or generate) the channel select tones to change the channel of the Tait T800II at the repeater site. The output from the Midian TRE2 is connected to the Tait TM8250 via the Auxiliary Connector on the rear of the radio.

To Select a Marine Channel the appropriate key on the Midian TRE2 is selected and the programmable function key "F4" on the Tait TM8250 is pressed. This sends the channel select tone to the Repeater site. Here it is received by a Tait T8110. A Tait TMAA01-01 Line Interface Board in the option space of the TM8110 provides a 4 wire interface to pass the channel select tones and voice communication to the Tait T803 channel selector.

The Tait T803 selects the channel of the T800II via the channel select lines. We have also connected these lines to the external BCD Channel Select lines of the TM8115. This causes the radio to switch to a channel which corresponds to the selected marine channel.

We programmed each channel of the TM8110 with a different Transmit SELCALL number. The SELCALL parameters have been set to send the SELCALL on the leading edge of the transmission.

This SELCALL is received by the TM8250 at the Coast Guard control room. Using the address book we linked this received SELCALL to enable the TM8250 to display Marine 06, Marine 12 or which ever channel was selected. This enables the operator to confirm that the required channel was selected.

The radio coverage now extends to a range of approximately 80Km in all directions around Barbados. In addition to the Marine channels other frequencies in the 150-174MHz band are used to provide secure communication.

Another VHF TM8200 installed on the Coast Guard ship HMBS Trident gives access to Marine Channels as well as other channels for secure communication.  The built in voice inversion scrambler further enhances the level of security for their operations.

Lord Nelson, Bridgetown, Barbados - erected in 1813, 27 years before London's Lord Nelson column. Sculpted from bronze by Sir Richard Westmacott, it is considered to be an accurate likeness of the British Admiral.

T800 Series II Base Station

Tait T803 Tone Remote

Midian Electonics TRE2
remote tone encoder

Tait TM8250 mobile radio

Tait TMAA01-01
Line Interface Board

Tait TM8110 mobile radio