Implantable VHF Systems (IMP)

Historically implants have been used to instrument animals to monitor physiological parameters such as core body temperature, subcutaneous temperature, and heart rate. In early studies there were many concerns over the potential adverse health effects of implant surgery and long term implantation of the system in the body of subject animals. Early reports and observations on several species of mammals, birds, and reptiles implanted for extended time periods indicated that implantation did not seem to adversely affect the behavior of the animal, induce a generalized inflammatory response, or prevent the reproduction of the species that were studied. It was noted that implants were "walled off" soon after implantation. Implants have been successfully removed from animals as long as 7 years after initial implantation surgery. In many instances animals carrying implants have successfully reproduced born and reared young. Although much of this information is anecdotal and has been collected as simply observations during studies specifically addressing other research topics, field reports on the health issues of implanted animals have been extremely favorable. If you choose to use an implant device in a study, Telonics recommends that you review the appropriate literature and consult with the appropriate oversight entities responsible for animal care, health, and treatment at your institution or agency.

Implants though initially used to monitor physiological parameters have more recently been used on numerous species which have a body morphology not suited to wearing external transmitting units. For example, otters simply do not wear collars well and harnessing techniques have been shown to be ineffective and in some cases dangerous to the animal's survival in its environment. Similarly snakes, lizards, and many species of fish are only instrumented using implant technology.

In other applications, the presence of an external device can influence the individual interaction with predators, conspecifics, or even offspring. Therefore in some behavioral studies implant technology is the preferred instrumentation technique because there are no external marks or devices.

Other applications include detection or parturition, the onset of disease processes, or estrous. Radio transmitter implant technology has developed steadily over the years and is today a mature technology for scientific research.

The first step in selecting an implantable transmitting subsystem is determining the appropriate size and weight for the configuration, which includes the transmitting electronics, power supply, and packaging. Often the size and weight of an implant can be greater than with configurations placed on the animal using an external attachment such as a collar. This is especially true with smaller subjects. This is not a recommendation to use the largest implant, but recognition that implants can often be positioned near the center of gravity of the animal, where more weight can be carried and the positioning of the unit is less likely to interfere with normal behavior.

Key Features

  • These implant systems have a dual water barrier. This double barrier system makes the implant less subject to mechanical damage and reduces the chance for long moisture penetration over the life of the transmitter. This approach represents the best and most reliable packaging available for implants.
  • All Telonics implants (with the exception of the CHP series) are microprocessor controlled.
  • Most configurations can be refurbished to the original configuration and returned to the user with a reinstated warranty.
  • Implants provide a great alternative approach for instrumenting smaller animals, rapidly growing young animals, or species with body forms that prohibit attaching external units.
  • Heart Rate units synchronize the transmitter pulse rate to the heart rate of the animal.
  • Although implants often have less range, as compared to externally mounted units, Telonics "tunes" the implant's antenna to match to the dialectic of the body maximizing range performance of the system.
  • Micro-miniature Implantable Subsystems are suited to implantation in smaller species

Standard Implantable Subsystems

Standard Implantable
Subsystems using Internal Antennas

Click here for
Micro-miniature Implantable Units


Config. Dimensions L x Dia (in, cm) Unit Weight (g) Operational Life
@ 60 BPM
Std. Pow (months)
Operational Life
@ 60 BPM
Low Pow (months)
Control Options
IMP-100-2 1.6 x 0.7
4.1 x 1.8
11 1.8 1.5 MK12 MS6, MA, MS9, MDC, MS4, MS5
IMP-130-2 2.1 x 0.75
5.3 x 1.9
19 4.8 7.1 MK12 MS6, MA, MS9, MDC, MS4, MS5
IMP-140-2 4.2 x 0.75
10.7 x 1.9
40 10.9 15.6 MK12 MS6, MA, MS9, MDC, MS4, MS5
IMP-150-2 2.1 x 0.9
5.3 x 2.3
21 4.8 7.1 MK12 MS6, MA, MS9, MDC, MS4, MS5
IMP-200-2 2.4 x 0.9
6.1 x 2.3
25 8.9 13 MK12 MS6, MA, MS9, MDC, MS4, MS5
IMP-210-2 2.9 x 0.9
7.4 x 2.3
38 8.9 13 MK12 MS6, MA, MS9, MDC, MS4, MS5
IMP-310-2 3.7 x 0.9
9.4 x 2.3
38.5 13.9 19.9 MK12 MS6, MA, MS9, MDC, MS4, MS5
IMP-400-2 3.8 x 1.3
9.7 x 3.3
~95 36 52 MK12 MS6, MA, MS9, MDC, MS4, MS5
IMP-700-2 6.0 x 1.3
15.2 x 3.3
~158 68.4 95.7 MK12 MS6, MA, MS9, MDC, MS4, MS5

Data Logging Option (Option 350)

The Data Logging Option for MK-11 and MK-12 transmitters (Option 350) allows sensor data from the MS6 mortality-motion sensor, MA activity sensor, and/or the MS4 temperature sensor to be stored in transmitter memory and made available for download if the transmitter is able to be retrieved at the end of a study. Additional information regarding how these sensors work is provided in the Sensor Options section below. This option requires use of Telonics Data Converter to download the stored data.

When this option is selected, data from any to all of the three sensors can be stored in internal memory in the transmitter. The sensors can either be directed to also control pulse period/rate or not, in the same way they would function without the data logging option. As one example, if all three sensors were enabled, either the MA activity sensor or MS4 temperature sensor could be used to control the transmitter’s active/alive pulse period, and the MS6 mortality-motion sensor would define the inactive/mortality pulse period after time-out without the required amount of motion.

For the MS6 motion-mortality sensor, the data logging records each date and time the sensor switches from active/alive to inactive/mortality or back. (The most recent 9-16 such transitions are recorded even without this option, but this option stores all such transitions).

For the MA activity sensor, the data logging option stores accelerometer data at user-defined intervals. These intervals may be the same throughout the anticipated life of the transmitter or they may change “seasonally”. The activity data recorded is the number of active seconds (or other defined classification interval) during a defined collection interval. For example the number of active seconds in a one hour collection interval would be saved as a number between 0-3600. User’s also select whether or not the collected activity data controls the transmitter’s pulse rate. If selected, the activity collection schedule for pulse rate control can either match the schedule for data which is logged, or it can be different.

For the MS4 temperature sensor, the data logging option stores temperature data at user-defined intervals (in 0.16oC increments). These intervals may be the same throughout the anticipated life of the transmitter or they may change "seasonally". User’s also select whether or not the collected temperature data controls the transmitter’s pulse rate. If selected, the temperature collection schedule for pulse rate control can either match the schedule for data which is logged, or it can be different. However, sampling to control pulse rate has a maximum interval of 18 hours and it remains constant for the life of the transmitter (no seasonal changes).

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 > -20°C) 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
MS6 Mortality - Motion Sensor
MA Activity Sensor
MS4 Temperature Sensor
MS5 Temperature-triggered Mortality Sensor
Sensor descriptions available separately

Sensor Options for VHF Transmitters using the MK-11 or MK-12 Electronics

MK-11 or MK-12 Sensor Options

Legacy Products

The information below is provided for individuals who are still deploying these older systems. Some of the system information or limitations, information on frequency allocation or usage, and/or comments made on "state of the art" may be time sensitive or even outdated. Please contact Telonics if you have any questions about the information provided in this section.

Telonics still supports and refurbishes the following products but no longer sells them new:

Micro-miniature Implantable Subsystems

Implantable Units

Click here for Standard Implantable Subsystems

Micro-miniature Implant Subsystems allow the instrumentation of smaller species of animals. The configurations are based on our CHP transmitter. To minimize the size of these configurations very small batteries are used. The smaller battery system limits the operational life of the configuration and also limits the radio frequency (RF) power that can be transmitted by the unit. The CHP electronics are matched to these small battery systems to avoid damaging the batteries yet provide as much range performance as is possible from the configuration. In order to further maximize range of these configurations, they are made with highly flexible external antennas that increase the radiated power. This common configuration is often used in fish and snake applications. Whenever this option is utilized, the implant is internally cast with a polymer and coated in physiological wax to minimize moisture penetration. However, this design is only water resistant - and the penetration of the wax coating by the antenna provides a potential moisture path that ultimately allows, in the long term, penetration of body fluids. The time-frame to moisture penetration is related to the type of external antenna structure selected as well as the flexation and strain placed on the antenna in the body. This technology is best suited to studies 3 to 6 months in duration.

Config Dimensions L x Dia (in, cm) Unit Weight (g) Transmitter Electronics Operational Life @ 60BPM (months) Operational Life @ 35BPM (months) Conventional Sensor Options
IMP-CHP-5P 1.44 x 0.62 x 0.37
3.66 x 1.57 x 0.94
6.8 CHP 8.5 13.6 conventional S2 temp
IMP-CHP-6P 1.0 x 0.62 x 0.37
2.54 x 1.57 x 0.94
3.7 CHP 4.2 6.8 conventional S2 temp
IMP-CHP-7P 0.83 x 0.45 x 0.37
2.11 x 1.14 x 0.94
2.2 CHP 1.6 2.7 conventional S2 temp
IMP-CHP-8P 0.90 x 0.42 x 0.25
2.29 x 1.07 x 0.64
1.2 CHP 0.7 1.1 conventional S2 temp

**Note: The CHP micro miniature transmitter is designed for use with a small battery system. The power output is matched to the power provided by the small battery. Therefore the standard power for an IMP/CHP is much lower than the standards power for a MK8 or MK9 subsystem. This is true of micro miniature transmitter technology in general and throughout the industry.

Specifications for Transmitter Electronics

CHP Conventional Control Options

OPT. S2 Temperature Sensor. Sensor provides pulse rate which varies according to temperature within the transmitting subsystem. User specifies desired pulse rate at anticipated median temperature and approximate range of temperatures to be monitored. Pulse rate increases at higher temperatures and decreases at lower temperatures.

Cautionary Notes for Implantable Subsystems

1. Most Telonics implantable telemetry transmitting subsystems utilize an internal transmitting antenna structure. The structure is contained inside the packaging of the implant. This type of antenna can be tuned to either air or the dielectric of the body. The tuning choice will affect where (in air or in the body) the maximum range performance will be achieved. If the unit is tuned to air, the unit's best performance will be achieved when air surrounds the implant. If the implant antenna is tuned to the dialectic of the body, the best performance from the implant will be achieved when the implant is actually inside the body cavity. Note: When testing, it is necessary to place the implant in the medium in which it will be expected to operate. This is particularly true when trying to obtain more accurate range performance test data.
For extremely large bodied animals (over 100 pounds), it should be noted that the large mass reduces the effective radiated power of the implant, thereby reducing the range performance of the system. When implanting small terrestrial mammals, the implant is often carried only a few inches off the surface of the earth and thus the range is reduced because line-of-sight range is also reduced under these conditions.

2. Cold method sterilization should be utilized when sterilizing units prior to implantation. The physiological wax can melt with hot method sterilization techniques compromising the units' moisture repelling properties. Also note, units should be stored in a cool environment (such as a cooler) during transportation in vehicles, or kept in a cool environment during periods of storage.

Technical Note about Sterilization Methods