BST 75-216 OPERATOR’S MANUAL (216 MHz) Mini Base Station Transmitter 357 West 2700 South • Salt Lake City, Utah 84115 • Phone: (800) 496-3463 • Fax: (801) 484-6906 • www.comtek.
TABLE OF CONTENTS Introduction ........................................................... 1 Equipment Placement ............................................... 2 Power Requirements ....................................................... 2 Remote Antenna ...................................................... 3 Screw-in Whip Antenna ............................................ 3 Audio Input Connections ............................................... 4 Audio Adjustments ...........................
INTRODUCTION BST 75-216 Mini Base Station Transmitter T he BST 75-216 mini base station transmitter meets the highest professional standards while offering outstanding value and the most advanced technology available. This versatile and innovative transmitter is simple to use, yet it has sophisticated features such as “Flash Memory” 57-channel programmability with a synthesized manual 10-channel selectable user-switch.
OPERATING INSTRUCTIONS Equipment Placement If the BST 75-216 base station is to be rack mounted, a remote antenna must be used. The base station should be mounted away from equipment that uses large power transformers to reduce 60 Hz hum possibilities. Special Note: When using the base station in close proximity to other audio equipment, ensure that the audio equipment is not susceptible to RF interference.
OPERATING INSTRUCTIONS Remote Antenna When the BST 75-216 base station transmitter is to be rack mounted for permanent installation, a remote antenna must be used. For high performance when greater coverage is required, the Phase-Right or Mini-Mite 1/2 wave omni antenna should be used. These antennas must be placed vertically polarized up to 15 feet away from the transmitter with the coaxial cable supplied. The highest possible antenna placement away from any metallic object is best.
OPERATING INSTRUCTIONS Audio Input Connections The BST 75-216 base station transmitter uses an XLR-3F connector with a “Combo” phone jack. The XLR portion of the connector will accept a true balanced or unbalanced line level signal up to +20 dBm. The 1/4” mono jack portion of the connector can be used for AUX level audio or line level audio up to +5 dBm. It also can be used to directly phantom-power most two-conductor electret headset microphones.
OPERATING INSTRUCTIONS Audio Processing Circuit The audio processing system of the BST 75-216 incorporates a peak-level compressor to prevent over-modulation and reduce audio distortion at high levels. This compressor has a very fast attack time and a carefully controlled decay time to optimize the dynamic performance of the audio processing system. (The VU meter will indicate this compressor action when the red LEDs are illuminated.
BST 75-216 FRONT PANEL 1 2 3 4 5 6 1 OPTIONAL ANTENNA: Used for mobile applications. 2 POWER SWITCH: Turns the transmitter on or off. 3 POWER LED INDICATOR: Illuminates when the power is on. 4 VU METER: Displays the audio level being used for modulation. (See Audio Adjustment Section.) 5 ANTENNA INDICATOR: Flashes when transmitter detects coaxial cable shorts and open conditions, bad antenna load. 6 RACK-MOUNTING SCREWS: Used for mounting BST 75-216 to rack-mounting panels.
BST 75-216 REAR PANEL 13 Located on bottom of transmitter 7 8 9 10 11 12 7 DC INPUT JACK: Requires 12V DC at 200 mA source. (Positive or negative center pin.) 8 CHANNEL SELECTOR SWITCH: Selects the frequency on which the transmitter will operate. (See Frequency Information Section.) 9 EXTERNAL ANTENNA JACK: BNC connector provides a standard 50 ohm RF output for use with an external antenna. 10 RF POWER SWITCH: Adjusts the RF power output of the transmitter (High-100 mW, Mid-50 mW, Low-25 mW).
BST 75-216 FREQUENCY INFORMATION SELECTED CHANNELS (STANDARD PROGRAM) CHANNEL SWITCH POSITION AVAILABLE 216 MHz “FLASH MEMORY” PROGRAMMABLE CHANNELS FREQUENCY CHANNEL FREQUENCY CHANNEL 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 216.0125 MHz 216.0375 MHz 216.0625 MHz 216.0875 MHz 216.1125 MHz 216.1375 MHz 216.1625 MHz 216.1875 MHz 216.2125 MHz 216.2375 MHz 216.2625 MHz 216.2875 MHz 216.3125 MHz 216.3375 MHz 216.3625 MHz 216.
BST 75-216 FREQUENCY INFORMATION Multiple Channel Operation When multiple transmitters (more than two) are used in the same proximity, intermodulation interference can occur. This condition is common to all radio receivers to some extent when multiple transmitters are used in the same operating area. The RF signals will “MIX” together generating additional signals.
BST 75-216 ACCESSORIES Included Accessories 1. C-75 Carrying case 2. BST 75-216 Operator’s manual 3. SLW 75-216 Short loaded whip antenna and bracket 4. AP-12V1-75 Universal switching power supply (12V DC output) 5.
BST 75-216 ACCESSORIES Optional Accessories 1. Mini-Mite 1/2 wave omni antenna 2. Phase-Right coaxial antenna 3. PRA Phase-Right antenna mount 4. HM-100 Behind-the-neck directional boom microphone with 1/4” phone jack plug 5. RMK 75-4 Quad rack-mount face plate 6. RMK 75-2 Double rack-mount face plate 7.
BST 75-216 SPECIFICATIONS Audio Inputs: • Line level balanced input 0 dBm for 80% modulation (+20 dBm max, XLR-3F) • Unbalanced input (+5 dBm Max) or two wire electret microphone with bias voltage for electret microphone (-35 dBv at 5 K ohms) with 1/4” phone jack. Connectors: • XLR-3F Combo with 1/4” phone jack • Barrel type 5.5mm X 2.
WARRANTY AND SERVICE Warranty COMTEK transmitters and receivers are warranted to be free from defects in workmanship and material under normal stand-alone use and conditions for a period of two years from date of original purchase. Items such as headphones, earphones, neckloops, and cords are warranted to be free from defects in workmanship and material for a period of 90 days from the date of original purchase. Batteries are not covered by this warranty.
357 West 2700 South • Salt Lake City, Utah 84115 • Phone: (800) 496-3463 • Fax: (801) 484-6906 • www.comtek.
