Electromagnetic field monitors measure the exposure to electromagnetic radiation in certain ranges of the electromagnetic spectrum. This article concentrates on monitors used in the telecommunication industry, which measure exposure to radio spectrum radiation. Other monitors, like extremely low frequency monitors which measure exposure to radiation from electric power lines, also exist. The major difference between a "Monitor" and a "Dosimeter" is that a Dosimeter can measure the absorbed dose of ionizing radiation, which does not exist for RF Monitors. Monitors are also separated by "RF Monitors" that simply measure fields and "RF Personal Monitors" that are designed to function while mounted on the human body.

Introduction

RF monitor comparison

Electromagnetic field monitors, as used in the cellular phone industry, are referred as "personal RF safety monitors", personal protection monitors (PPM) or RF exposimeters.[1] They form part of the personal protective equipment worn by a person working in areas exposed to radio spectrum radiation. A personal RF safety monitor is typically worn either on the torso region of the body or handheld and is required by the occupational safety and health acts of many telecommunication companies.

Most of the scientifically proven RF safety monitors are designed to measure the RF exposure as a percentage of the two most common international RF safety guidelines: International Commission on Non-Ionizing Radiation Protection (ICNIRP) guidelines[2] and the U.S. Federal Communications Commission (FCC).[3] The ICNIRP guidelines are also endorsed by the WHO.[4] RF personal safety monitors were originally designed for RF Engineers working in environments where they could be exposed to high levels of RF energy or be working close to a RF source, for example working at the top of a telecommunication tower, or working on the rooftop of a building where transmitting antennas are present. Most international RF safety programs include the training and use of RF personal safety monitors and the IEEE C95.7 specifies what is a RF Personal Monitor.[5]

In some cases the RF safety monitor comes in a version or mode for the general public.[6] These meters can then be used to determine areas where the public might be exposed to high levels of RF energy or used to indicate the RF level in areas where the general public has access.

Specification

The specifications of a RF monitor determines the work environment where could be applicable. Wideband RF monitors can be used at a broader variety of base station sites than for example a narrowband, cellular RF monitor which is designed only to be used in the mobile telephone- and data networks. IEEE Std C95.3 states that "In the region between 1-100 GHz, resistive thermoelectric dipoles are used as sensors with a background of lossy material to reduce the effect of scattering from the body. Electrically short dipoles with diode detectors as sensors may cover a portion of this range". The results of monitors which do not incorporate "lossy material" to reduce the effects of scattering, are questionable on the body.

The type of response is a basic feature of any RF personal monitor and can be expressed in two basic parameters:

  • Directivity: Some of them have an isotropic response, which means that they are able to measure RF fields from any space direction. Others, like radial field monitors, have a partial space coverage, and have to be worn in a specific way in order to provide a correct reading.
  • Frequency response:
    • Flat response: units that have a flat response for all the frequency range covered, i.e. the response does not change with frequency.
    • Shaped response: contain frequency dependent sensors that automatically weight the detected RF fields in accordance with frequency-dependent RF exposure limits.

It is common that RF personal monitors provide results as a percentage (%) of frequency-dependent limit values of a specific standard (sometimes called reference levels or MPE, maximum permissible exposure). It is important to be careful interpreting exposure during an alarm condition based on a % result; shaped response RF personal monitors will provide a result as a % of the standard, independently of the frequency, while flat response monitors will provide a result as a % of a particular value (not frequency-dependent), so it is important to know which is the particular value this % is referring to.

Some RF personal monitors have different versions, shaped to each standard, so they will be more accurate, but can be used only for that standard. Others have a single version, so will be less accurate, but can be used for different standards.

Usually, the alarm of most RF personal monitors is triggered by instant values, however, standard limits are specified as time-averaged values. Some RF monitors have the possibility to trigger alarms based on average values, which is a better indication of the real exposure situation (as an example, an instant value can be at 200% while the average being below 100%).

As they are typically small, portable units, they are usually equipped with only a few LEDs for a rough field level indication (50%, 100%, etc). Nevertheless, some of them have a datalogger that allows to download the measurements, check for the exact values, and keep a history record of the exposures. Wavecontrol's WaveMon has available a GPS and altimeter to include position information to the data records.

Other specifications that may be relevant, depending on the application are battery characteristics (lifetime, ways to change or recharge), dimensions, weight, and operating temperature.

The following table shows different basic specifications of some RF monitors:

SpecificationEME Guard XS[7]Narda RadMan XT[8] Narda RadMan 2LT[9] Narda RadMan 2XT[9] WaveMon RF-8[10]SafeOne[11]FieldSENSE60[12]EME Guard Plus[13] WaveMon RF-60[14]Nardalert S3[15] EME Guard XS 40GHz [16]
Frequency Range80 MHz – 6 GHzE-Field

1 MHz - 40 GHz (ICNIRP)

3 MHz - 40 GHz (FCC)

10 MHz - 40 GHz (SC6)

H-Field

27 MHz - 1 GHz (ICNIRP,

SC6)

3 MHz – 1 GHz (FCC)

 E-Field

50 MHz – 8 GHz

H-Field

50 MHz – 1 GHz

 E-Field

900 kHz – 60 GHz (ICNIRP models)

3 MHz – 60 GHz (FCC models)

10 MHz – 60 GHz (SC6 models)

H-Field

27 MHz – 1 GHz (ICNIRP, SC6 models)

3 MHz – 1 GHz (FCC models)

 E-Field: 300 kHz - 8 GHz

H-Field 3 MHz – 1 GHz

10-10000 MHz E-Field 50 MHz - 60 GHz

H-Field 50 MHz – 1 GHz

1 MHz- 40 GHz E-Field: 100 kHz - 60 GHz

H-Field: 3 MHz - 1 GHz

100 kHz – 100 GHz 1 MHz – 40 GHz
DirectivityIsotropic (Tri-axial)Isotropic (Tri-axial) Isotropic (Tri-axial) Isotropic (Tri-axial) Isotropic (Tri-axial)Isotropic (Tri-axial)Isotropic (Tri-axial)Isotropic (Tri-axial) Isotropic (Tri-axial)Radial and Dual-polarized Isotropic (Tri-axial)
Frequency Response Flat Shaped Shaped Shaped Shaped Flat Shaped Flat Shaped Shaped Flat
50/60 Hz immunityN/A1 kV/m 10 kV/m 10 kV/m 30 kV/mN/AN/AN/A 30 kV/m100 kV/m N/A
Designed to be worn on the Body (per IEEE C95.3)NoYes Yes Yes YesNoYesNo YesYes No
Reference standardICNIRP 2020

FCC

Safety Code 6 2015

User-definable

2004/40/EC

ICNIRP

FCC

Safety Code 6

ICNIRP General Public

(separate model)

 ICNIRP

FCC

Safety Code 6

ICNIRP General Public (separate model)

 ICNIRP

ICNIRP General Public

FCC

Safety Code 6

 FCC

EU Directive (2013/35/EU)

ICNIRP

Safety Code 6 (2015)

 ICNIRP

FCC

IEEE

NCRP

Safety Code 6

ICNIRP

FCC

IEEE

NCRP

Safety Code 6

ICNIRP 2020

FCC

Safety Code 6 2015

User-definable

 FCC

EU Directive (2013/35/EU)

ICNIRP

Safety Code 6 (2015)

NATO

 FCC

IEEE C95.1

Safety Code 6 (2015)

ICNIRP

 ICNIRP 2020

FCC 96-326 Safety Code 6 2015 2013/35/UE

Exposure level indicators 1 X LED => 1%

2 X LED => 5%

3 X LED => 20%

4 X LED => 100%

5 X LED => 225%

6 X LED => 500%

7 X LED => 2000%

(Broadcast 100 MHz: Visual & Audio Alarms

Activated 5 to 350 V/m

User-definable at factory)

 1 X LED => 12.5%

2 X LED => 25%

3 X LED => 50% (Buzzer alarm)

4 X LED => 100% (Buzzer alarm)

 1 X LED => 5%

2 X LED => 10%

3 X LED => 25%

4 X LED => 50%

5 X LED => 100%

6 X LED => 200%

=> 50%: visual, audible and vibration indicators
=> 100%: strong visual, audible and vibration indicators
 1 X LED => 5%

2 X LED => 10%

3 X LED => 25%

4 X LED => 50%

5 X LED => 100%

6 X LED => 200%

=> 50%: visual, audible and vibration indicators
=> 100%: strong visual, audible and vibration indicators
 1 X LED => 10%

2 X LED => 25%

3 X LED => 50%

4 X LED => 75%

5 X LED => 100%

6 X LED => 200%

Visual, Audio & Vibration Alarms.

Adjustable by user.

 1 X LED => 2%

2 X LED => 5%

3 X LED => 10%

4 X LED => 25%

5 X LED => 50% (0.75 Hz buzzer alarm)

6 X LED => 100% (1.5 Hz buzzer alarm)

7 X LED => 200% (3 Hz buzzer alarm)

 1 x LED=> 6%

2 x LED=> 12%

3 x LED=> 25%

4 x LED=> 50%

5 x LED=> 100%

6 x LED=> 200%

(Visual, Audio and Vibration alarms adjustable )

 1 X LED => 10%

2 X LED => 25%

3 X LED => 50%

4 X LED => 75%

5 X LED => 100%

6 X LED => 200%

Visual, Audio & Vibration Alarms.

Adjustable by user.

 LED Display of the Actual Value

Two LED Alarm Indicators (Visual)

Two Audio Alarm Indicators

Vibration Alarm Indicator

User Variable in 50% increments

Defaults are 50 and 200%


 1 X LED => 0.4%

2 X LED => 2%

3 X LED => 10%

4 X LED => 40%

5 X LED => 100%

6 X LED => 200%

7 X LED => 800%

Data loggerNoYes Yes Yes YesNoYesYes YesYes (Option) No
GPS No No No No Yes No No No Yes No No
Altimeter No No No No Yes No No No Yes No No
Battery life>100 hours200 hours 800 hours

(Rechargeable via USB)

 800 hours

(Rechargeable via USB)

 >200 hours (Rechargeable via USB) 2,000 hours6-12 months average use Recording mode:

>300 hours

Non-recording mode: >3 months (8 hours/day)

 >200 hours (Rechargeable via USB)25 hours (Rechargeable via USB) > 1000 hours
Dimensions132.5 x 48.5 x 28.7 mm163 x 41 x 37 mm 165 x 47 x 31 mm 165 x 47 x 31 mm 174 x 42.5 x 33 mm 58 x 105 x 23 mm146 X 42 X 26 mm172.6 X 59 X 35.5 mm 174 x 42.5 x 33 mm117 x 83 x 32 mm 132.5 x 48.5 x 28.7 mm ( LxWxH)
Weight120g130g 185g 185g 190g88g115g275g 190g230g 120 g
Operating temperature-10°C to +50°C-10°C to + 55°C -10°C to + 55°C -10°C to + 55°C -20 °C to +50 °C-10°C to +40°C-20°C to +50°C-20°C to +55°C -20 °C to +50 °C-10°C to +50°C-10°C to +50°C
Calibration interval24 Months36 months 36 months 36 months 24 Months24 Months24 Months24 Months 24 Months48 months 24 Months
NIST/ILAC Traceable CalibrationNoYes Yes Yes YesNoNoNo YesYes No
Fall Detection AlarmNoNo No No YesNoYesNo YesNo No
Approx. price USD$550$1000 $600 $1200 $900$700$799$999 $1400$1700 $799

Operating instructions

Each specific personal RF safety monitor has its own operating instructions. And most of the monitors have different operating modes. For instance, the Narda Radman has a mode in which it can be body worn by the operator, but it also has a probe mode where the operator can scan certain areas to find accurate exclusion zones.[17] The FieldSENSE on the other hand has a monitor and measure mode.[18] The measure mode is similar to the Radman's probe mode, but the monitor mode is used by mounting the FieldSENSE onto an inactive antenna and then it is safe to work on the antenna until the FieldSENSE raise an alarm to warn RF technicians that the antenna is live and that any work on the antennas should be ceased until deactivation is confirmed. The Wavecontrol's WaveMon[19] and Narda's RadMan 2[29] can be body-worn, and used off the body as a probe or as a monitor. Most of the RF monitors such as the FieldSENSE, EME Guard, WaveMon and the RadMan 2 also have a data logging functionality that can log the RF exposure of a worker over time.[20][21] The RadMan 2XT's RF detection mode with its tone search feature can locate leaks in waveguides and verify that an antenna is turned off. [30]

List of personal RF monitors

  • EME Guard Plus[22]
  • EME Guard XS[23]
  • EME Guard XS 40 GHz[24]
  • EME SPY Evolution[25]
  • Narda Radman XT[26]
  • Narda RadMan 2LT[9]
  • Narda RadMan 2XT[9]
  • Nardalert S3[27]
  • FieldSENSE60 [28]
  • FieldSENSE 2.0[29]
  • Public FieldSENSE[6]
  • SafeOne Pro SI-1100XT[11]
  • WaveMon RF-8[30]
  • WaveMon RF-60[31]

References

  1. ↑ Williams, Edmund A.; Jones, Graham A.; Layer, David H.; Osenkowsky, Thomas G. (2007). National Association of Broadcasters Engineering Handbook. Taylor & Francis. ISBN 9780240807515.
  2. ↑ "OSHA Technical Manual (OTM) | Occupational Safety and Health Administration".
  3. ↑ "Equipment Authorization - Measurement Procedures". 19 December 2014.
  4. ↑ "WHO/ICNIRP Conference on EMF Biological Effects" (PDF). World Health Organization. 2001-12-10.
  5. ↑ http://ieeexplore.ieee.org/xpl/login.jsp?tp=&arnumber=1611107&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Farnumber%3D1611107%7Ctitle"IEEE Recommended Practice for Radio Frequency Safety Programs, 3 kHz to 300 GHz," IEEE, International Committee on Electromagnetic Safety, New York, IEEE Std C95.7, 2014
  6. 1 2 "Public product info". FieldSENSE. Retrieved 2012-04-02.
  7. ↑ "EME Guard XS". RF Monitors EME Guard XS. mvg-world.com. Retrieved 2020-06-11.
  8. ↑ "Narda STS RadMan XT Datasheet" (PDF). Narda-sts.us. Retrieved 2012-06-06.
  9. 1 2 3 4 "Narda Radman 2". Narda-sts.com. Retrieved 2023-08-11.
  10. ↑ "WaveMon RF-8. Broadband Personal monitor". Waveconrol.
  11. 1 2 "SafeOnePRO Personal RF Safety Monitor PPE: Light, Tuff, All Cell Band".
  12. ↑ "FieldSENSE" (PDF). FieldSENSE. Retrieved 2012-04-02.
  13. ↑ "EME Guard Plus". RF Monitors EME Guard Plus. mvg-world.com. Retrieved 2020-06-11.
  14. ↑ "WaveMon RF-60 - 60 GHz RF Personal Monitor". Wavecontrol.
  15. ↑ "Narda Safety Test Solutions Nardalert S3 Datasheet" (PDF). Narda-sts.us. Retrieved 2016-06-06.
  16. ↑ "MVG OCCUPATIONAL RF SAFETY-EME Guard XS 40GHz". mvg-world.com. Retrieved 2021-05-05.
  17. ↑ "Radman - Measure and probe mode".
  18. ↑ "FieldSENSE - Measure and monitor mode".
  19. ↑ "WaveMon RF personal monitors". Wavecontrol.
  20. ↑ "Narda Safety Test Solutions" (PDF). Narda-sts.us. Retrieved 2012-04-02.
  21. ↑ "EME Guard". RF Monitors EME Guard. mvg-world.com. Retrieved 2020-06-11.
  22. ↑ "EME Guard Plus - MVG (Satimo)". mvg-world.com. 2020-06-11. Retrieved 2020-06-11.
  23. ↑ "EME Guard XS - MVG (Satimo)". mvg-world. 2020-06-11. Retrieved 2020-06-11.
  24. ↑ "EME Guard XS 40 GHz- MVG (Satimo)". mvg-world. 2020-06-11. Retrieved 2020-06-11.
  25. ↑ "EME SPY evolution - MVG (Satimo)".
  26. ↑ "Narda Radman XT" (PDF). Narda-sts.us. 2011-06-06. Retrieved 2012-06-06.
  27. ↑ "Nardalert S3 - Narda STS". Narda-sts.us. 2016-06-06. Retrieved 2012-06-06.
  28. ↑ "FieldSENSE 60 | Fieldsense". Retrieved 2021-09-28.
  29. ↑ "Occupational product info". FieldSENSE. Retrieved 2012-04-02.
  30. ↑ Broadband Personal Monitor. "Data Sheet WaveMon RF-8" (PDF). Wavecontrol.
  31. ↑ 60 GHz RF Personal Monitor. "Data Sheet WaveMon RF-60" (PDF). Wavecontrol.{{cite web}}: CS1 maint: numeric names: authors list (link)
This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.