TBT-550-3 VHF Trapsite Transmitter

Dimensions L x W x H (in, cm) Unit Weight (g) Notes Life @60BPM
Std Pow (months)
Life @60BPM
High Pow (months)
4.7 x 1.45 dia
11.94 x 3.68 dia
230 Designed primarily for monitoring leg hold traps. Whip antenna. 90 50

Lifetime estimates are based on continuous operation.

Telonics VHF Trapsite Transmitters are installed at the trapsite to signal triggering of a trap. After the trap has been set the transmitter continuously reports a "not triggered" condition (a specified pulse rate) to verify proper operation. When triggering has occurred the unit sends a faster pulse rate indicating the trap is sprung. The trapsite transmitter is supplied with a flexible "whip" antenna. This unit is typically attached to the trap "drag" and if the animal moves from the trapsite, the VHF signal can be used to locate the trapped animal.

Key Features

  • Hermetically sealed case allows for extended deployments at the most extreme temperatures and most humid/wet environments
  • Lithium power packs support operation from +70°C to -40°C but using these batteries necessitate shipping the entire unit as hazardous goods
  • Duty Cycling options are available on these units, but are seldom employed since the operational life of the trapsite unit is very long and the unit can be shut off when not in use
  • Continuous VHF operation lets the capture personnel know that the unit is functional and whether it is in triggered or not triggered mode
  • A special feature of the TBT series is the time since trap triggered option. This feature allows researchers to know how long it has been the trap was triggered, and in conditions where an animal is captured, how long the animal has been in the trap. This feature is optional and must be requested at the time of order
  • Units can be shut down with a magnet for storage and turned on for redeployment next trapping session or season
  • Units are refurbishable to original condition at the factory

Data Decoding for Time Since Trap Triggering

The Time Since Triggering event uses a variable pulse period to transmit the elapsed time since the trap was triggered. The user specifies:

  • A pulse period indicating the trap is operational but has not been triggered
  • A pulse period to be transmitted immediately after the triggering event
  • The maximum elapsed time of concern since occurrence of the event (1 second to 1000 days)
  • A pulse period that corresponds to the maximum time of concern after the event occurs

Time since event example:

  • Event type: Time since input triggered
  • Time scale: Linear
  • Pulse period at input trigger: 600 ms (100 BPM)
  • Pulse period 3 days since input trigger: 1500 ms (40 BPM)
  • Equation: Elapsed seconds = Pulse Period * 288.0209 - 172814
  • Resolution: 00:04:48 (per 1 ms change in pulse period)

The beacon can vary the pulse period with either a simple linear scale or a segmented scale of 2-8 pieces. Linear scale provides constant resolution. Segmented scales allow finer resolution of elapsed time immediately after the event occurred and coarser resolution later on. Each segment has resolution that is twice as coarse as the segment before it. Telonics provides a graph and linear equations to convert an observed pulse period into an elapsed time.

Specifications for Transmitter Electronics

MK11/12 Transmitter General Specifications

MK-11 and MK-12 beacons are microprocessor controlled pulsed-CW transmitters, designed for operation within the 137 - 225 MHz frequency range. Each MK-11 beacon transmits on a single, field-programmable frequency (within the frequency range that is ordered). MK-11 beacons also support 3 field-programmable power levels. The MK-12 beacon is crystal based, and therefore each beacon is built to operate on a specific frequency and with a specific power output (four power levels to choose from when ordering).

Frequency Range MK11:
137 - 143 MHz (option 700),
143 - 156 MHz (option 710),
154 - 164 MHz (option 720),
162 - 174 MHz (option 730),
164 - 182 MHz (option 740),
182 - 201 MHz (option 750),
201 - 222 MHz (option 760)

140 - 225 MHz
Frequency Tolerance MK11:
Calibration: ±3 ppm max at room temperature / ±5 ppm from -40° to +70°C
Aging: <1ppm/yr
Shock: <1ppm 3000g x 0.2ms x ½ sine x 3 directions

Calibration: ±17 ppm at room temperature / ±25 ppm from -40° to +70°C
Load: <7ppm typical for VSWR < 6:1
Supply Voltage: <3ppm typical over supply voltage range at 25°C
Aging: <1ppm/yr
Shock: <1ppm 3000g x 0.2ms x ½ sine x 3 directions
VSWR Stability MK11: RF output stable to 10:1 VSWR, all phases.
Radiated harmonic levels are degraded with poor load VSWR.
Spurious emission specification maintained for > 10:1 VSWR.

MK12: RF output stable to 5:1 VSWR, all phases.
Radiated harmonic levels are degraded with poor load VSWR.
Spurious emission specification maintained for > 5:1 VSWR.
Output Power
MK11: Field Programmable using TPP
Transmit Power Peak Power Output
Relative to Medium Power
Low 0.5 * Medium Power
High 2.0 * Medium Power

MK12: Ordering Options for Power Level
Option Transmit Power Peak Power Output Levels
Relative to Standard Power
200 Low (Temperature > -20C) 0.5 * Medium Power (Higher efficiency)
202 Low 0.5 * Medium Power
204 Medium  
206 High 2.0 * Medium Power

Output power is measured into 50 Ω load. Effective Isotropic Radiated Power (EIRP) varies, depending on packaging, antenna configuration, and immediate environmental conditions.
Emission Designator MK11: 2k00P0N -
California users: These transmitters meet the California requirement of EIRP < 0.009 W for all conditions.
MK12: 1k00P0N -
California users: These transmitters exceed the emission designator requirement of 2k00P0N for operation in California. The 1k00P0N emission designator is identical to the 2k00P0N except that it occupies only half of the 2 kHz bandwidth allowed by the State of California for wildlife tracking.
Harmonic and Coherent Spurious Suppression MK11: <-30 dBc into 50Ω load
MK12: Coherent Spurious <-10 dBc
Spurious Suppression MK11: <-35dBc typical at > 10kHz offset from carrier
MK12: Non-Coherent Spurious <-50 dBc
RF Pulse Width 15 msec standard
Can optionally be configured from 10 - 250 msec
Pulse Period Configurable from 250 - 5000 msec (12-240 Bpm)
RTC Accuracy / Seasonal Timing Temperature Compensated:
± 12min/yr max
Temperature Range -40°C to +70°C (Note: Temperature range is for the transmitter only. The power supply must provide the required peak current and voltage requirements for the transmitter over the expected temperature range.)
Shutdown Component Externally shutdown by presence of a small magnet
Available Sensors
• Motion Sensor (3-axis accelerometer) - Option 500

- Activity - Used to determine the level of activity of the study animal. The animal's motion is sensed once each second to determine "active" Classification Periods (programmable in length). At the end of a programmable Update Period, the number of "active" Classification Periods is used to establish either: a) one of two programmable, fixed pulse periods (i.e., Low activity level, or High activity level), or b) to control a variable pulse period that defines the measured amount of activity.

- Mortality - Provides an "active/alive" or "inactive/dead" pulse period depending on the activity level of the study animal. Motion is sensed once each second and a tally is made of "active seconds" over a programmable period of time (the Mortality Period). If the count of "active seconds" over this period of time is below a programmable threshold, the animal is deemed dead and the unit transmits a programmable, fixed pulse period. Otherwise, the animal is considered alive, in which case, the unit transmits according to its normal programmed behavior. This can alternatively be used to trigger the "Time Since Event" function.

• Temperature Sensor

- Temperature measurement - Temperature is measured via the sensor specified when the unit was ordered/built (see table below). The temperature is measured at a programmable time interval, and is used to control a variable pulse period.

- Mortality - Temperature is measured via the sensor specified when the unit was ordered/built. (Default is Opt. 400, centered at 37°C.) When the temperature is below a programmable value, the animal is deemed to be dead, causing the unit to transmit at a programmable, fixed pulse period. Otherwise, the animal is considered to be alive, in which case, the unit transmits according to its normal programmed behavior. This can alternatively be used to trigger the "Time Since Event" function.

Temperature sensor specs:
Sensor Type Range Resolution Accuracy (uncal) Accuracy (calibrated*) Opt #
Thermistor Center temp = 14°C -40 to +70°C 0.390° @ -40°C
0.076° @ 14°C
0.342° @ 70°C
±0.39°C typ
±2.0°C max
  401 - Onboard
406 - Remote
-10 to +32°C <=0.1°C ±0.28°C typ ±0.08°C + CalErr** typ. (Cal @ 14°C)
Thermistor Center temp = 37°C -40 to +70°C 1.041° @ -40°C
0.087° @ 37°C
0.162° @ 70°C
±0.47°C typ
±3.35°C max
  400 - Onboard
405 - Remote
+14 to +47°C <=0.1°C ±0.28°C typ ±0.09°C + CalErr** typ. (Cal @ 37°C)
Digital -40 to +70°C 0.0625°C ±1°C max ±0.0625°C + CalErr** typ. (Cal @ any temp) 410 - Onboard

* Calibration is the responsibility of the user, consisting of a 1-point calibration at the listed temperature.

** CalErr is the Calibration Uncertainty which is the error inherent in the calibration procedure. This value is dependent on the end user's calibration procedure and equipment accuracy.

Related Products

HD 009245-001 Magnet Pull Lanyard for use with TBT and TBTR series units
HD 009245-001 Magnet Pull Lanyard for use with TBT and TBTR series units

Length 20.5 in (52.07 cm)

One HD 009245-001 is included with each trapsite transmitter.

TAS-1 Telonics Armor Shell for TBT-550-3

Click a thumbnail for a larger view.

Lithium Battery Shipping Regulations

Telonics, Inc. ships all systems containing lithium batteries in accordance with United Nation and US Federal regulations for shipping hazardous materials.

49 Code of Federal Regulations

IATA Dangerous Goods Regulations (current year)

Service Commitment

Since 1970, Telonics has built a reputation based on product quality, product support, service, and customer satisfaction. Telonics strives to produce the highest quality products, and to support those products accordingly.

Because of extreme conditions and the unpredictable nature associated with most telemetry applications, problems occasionally arise. Most problems can be resolved quickly. In all cases, we hope to be able to work in partnership with users to resolve problems to the user's satisfaction and to uphold our demonstrated commitment to excellence. If problems should arise, all products must be returned to our factory for failure analysis.

Warranty: VHF Transmitting Subsystems

The VHF Transmitting Subsystem includes the following main components: internal digital and radio frequency electronics comprising the transmitter, power supply (battery), exterior packaging, transmitting antenna and attachment. A refurbished Subsystem is warranted as if the Subsystem was purchased new, unless otherwise stated.

Telonics warranties only the following with respect to the Subsystem:
1.1 The internal electronics (excluding batteries) are warranted to be free from defects in materials and workmanship and to perform to the operational specifications over the specified operating temperature range as published by Telonics for the rated operational life of the Subsystem (as recorded on the final test data sheet accompanying the unit), up to a maximum of three (3) years from the date of initial shipment of the Subsystem by Telonics.
1.2 The exterior packaging integrity of hermetically sealed subsystems are warranted for the full operational life of the Subsystem, up to a maximum of three (3) years from the date of initial shipment of the Subsystem by Telonics.
1.3 The exterior packaging integrity of polymerically sealed subsystems are warranted for the operational life of the Subsystem, up to a maximum of one (1) year from the date of initial shipment of the Subsystem by Telonics.

Although each Subsystem is supplied with a power supply in the form of a battery, Telonics does not manufacture batteries (electrochemical cells), and therefore cannot warranty the battery lifespan, mechanical integrity or other battery performance issues. However, Telonics conducts extensive testing of all types of electro-chemical subsystems to determine suitability to the application. Once an electrochemical system is chosen for a configuration, testing procedures are employed at Telonics to evaluate every individual battery that is installed in each transmitting subsystem. Even using these advanced testing procedures it is not possible to determine a specific battery's lifespan or mechanical integrity.

Telonics conducts tests to assure that each unit is transmitting at the power level selected by the user. Actual range performance is a system characteristic dependent upon numerous conditions including receiver sensitivity and noise figure, receiving antenna tuning and pattern, transmitter antenna integrity, line of sight conditions in the field, and vegetation and habitat conditions and other factors specific to individual study sites. Therefore it is not possible to warranty a minimum range that will be achieved for units deployed in the field.

"Packaging integrity" as applicable to 1.2 and 1.3 above, is limited to normal wear as encountered on the animal.

It is the purchaser's obligation to make certain that it orders the correct size and type of Subsystem for the particular type and size of animal that the Subsystem will be applied to, and no warranty is expressed or implied for any failure to meet operational specifications due in whole or in part to use of an incorrect size or type of Subsystem.

No warranty is expressed or implied with regard to abnormal events or damage due to human actions such as gunshot damage, vehicle encounters, etc. Further, no warranty is expressed or implied with regard to damage resulting from misuse, accidents, unauthorized service, extreme conditions, or other causes not specifically enumerated herein.

The entire risk, as to the results and performance of the Subsystem, is assumed by the customer. Neither Telonics, nor its suppliers, shall have any liability to the customer or any other person or entity for any indirect, incidental, special, or consequential damage whatsoever, regardless whether Telonics has been told of the possibility of such damages or that such damages might be foreseeable. Telonics has no responsibility or liability for the claims of any third party. Telonics' and its suppliers' maximum aggregate liability shall not exceed the amount paid by the customer for the Subsystem.

Exercising the Warranty
If a defect occurs, return the Subsystem to Telonics within the applicable time frame noted above at the following address: TELONICS, 932 E. IMPALA AVENUE, MESA AZ USA 85204-6699. Telonics does not assume responsibility for loss or damage to equipment during shipment. Telonics does not assume responsibility for delays resulting from shipment on commercial or private carriers. We insure all equipment shipped from our facility and suggest that shipments to Telonics also be insured. Customer shall arrange for and pay all shipping, insurance and related charges incurred in the shipment of Subsystems to and from Telonics under this warranty.

Upon the timely return to our facility within the applicable time frame noted above, if the exterior packaging integrity and/or internal electronics (excluding batteries) are defective, the Subsystem will be replaced or repaired, at Telonics' sole discretion, at no cost to the customer, other than shipping charges. This remedy is the exclusive remedy. This product is supplied without any further warranties or conditions, expressed or implied, including warranties of merchantability, quality or fitness for particular reason or those arising by laws, statutes or trade usage or course of dealing.

The above warranty extends only to the original purchaser and does not cover any Subsystem which is resold or otherwise transferred from the original purchaser to another party. The warranty will be extended to customers who purchase the Subsystem directly from a Telonics-authorized distributor.