Assistive Listening Knowledge Base
  • Manufacturer operator's manual

BST-75 Synthesized Base Station Transmitter Operator's Manual (72-76 MHz)

From https://assistivelisteningknowledgebase.org/evidence/comtek-2011-bst-75-manual/ · record checked 9 October 2026

  • COMTEK Communications Technology
  • COMTEK Communications Technology (downloads page)

Manufacturer (COMTEK Communications Technology, which sells 72-76 MHz and 216 MHz transmitters and receivers for assistive listening, language interpretation and other uses)

Summary

A maker's manual for the 72-76 MHz base station in its large-area assistive listening kit for houses of worship, theatres and auditoriums, with its rules for running several transmitters.

Key findings

  • States that the transmitter operates in 72-76 MHz under FCC Part 90 at up to 120 mW, which the maker says gives "greater range and reliability than customary FCC Part 15 systems".
  • Warns that when more than two transmitters are used in the same area, intermodulation can cause interference, and that frequencies must then be coordinated by choosing them from one of its frequency groups (at 72 MHz, groups of four, three and two channels).
  • Advises that transmitters in different frequency groups be separated by twice the operating area, with at least 100 ft (about 30 m) between group operating areas.
  • Offers 88 programmable channels between 72.020 and 75.980 MHz, companded or non-companded to suit different receivers, with an audio response of 80 Hz to 10 kHz.
  • Its specifications state the transmitter is type-accepted under FCC Part 90.

Limits

A manufacturer's manual without measurements. It does not say whether a licence is needed to operate under Part 90 or how the separation rule was derived. Dated by its print line (18 January 2011); the maker's downloads page still offers it, alongside a 216 MHz model whose manual gives the same multi-transmitter rules.

Read the original

img1.wsimg.com/blobby/go/414496dc-67ac-402c-ac0d-00342b1b241d/downloads/BST-75%20Mmanual.pdf

Link checked . We link to the original and do not host copies.

Cited in

Cite this source

COMTEK Communications Technology. BST-75 Synthesized Base Station Transmitter Operator's Manual (72-76 MHz). COMTEK Communications Technology (downloads page). 18 January 2011. https://img1.wsimg.com/blobby/go/414496dc-67ac-402c-ac0d-00342b1b241d/downloads/BST-75%20Mmanual.pdf (accessed 9 October 2026).

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