The Acoustimeter is our most versatile microwave detector. It presents RF measurements as an audio signal, with LEDs and accurate readings on an LCD screen. It also measures both the peak and average readings at the same time. It covers the spectrum from TETRA all the way up to and beyond the 5.6 GHz WiFi and WiMax frequencies, and is sensitive down to 0.02 V/m, making it a suitable instrument for those with severe electrosensitivity.
The Acoustimeter has been designed to enable you to make a quick and informed judgement regarding the level and nature of microwave signals in your environment. It is a broadband instrument that accurately measures the totality of the radiation in the range 200 MHz to about 8000 MHz (8 GHz), which covers the frequencies used by most modern communication systems encountered in our everyday environment. The Acoustimeter was designed using the experience gained from many years of practical RF and microwave measurements.
The readings are shown on both an LCD display and two series of graduated LED lights. The LEDs update rapidly, and allow you to quickly gauge the levels in an area and find any hot-spots. The LCD display offers high accuracy with a lower update speed, giving you time to take note of the readings. It also has a speaker (and audio output socket for headphones or to feed to an audio recorder), allowing you to determine, with a small amount of practice, what type of device is creating the levels that are present. Sound samples are available on this page to help you identify what kind of signal your Acoustimeter is measuring. The sounds made by different transmitters can change with time, so these are meant as a rough guide only. If you are subject to a number of sources of RF, the sounds may intermingle and be less easily identified.
In areas where there is virtually no modulated microwave radiation (below the level of 0.02 V/m that the Acoustimeter is designed to detect), it is possible, with the volume turned fully up, to hear faintly some background clicking. This is from internal workings of the Acoustimeter and is not related to any external signal, and is therefore of no concern.
The Acoustimeter reads differently from some meters as:
- It has a very fast response (up to over 8 GHz and reacts to very short pulses)
- Peak readings are what they say – the highest sampled reading – though the sampling and processing rate means that there are some gaps and it will not always react to a SINGLE VERY short pulse (less than about 5 microseconds duration) – though it will react correctly to much shorter pulses that are regularly transmitted (such as from WiFi). The peak-hold reading on the LCD screen can be higher for some types of signal than the highest LED seen flashing as the Peak LED display does not show all the pulses in order to make it easier to see. The LCD peak-hold is the highest measured since switch-on. It is cleared by switching the meter off and on again.
- The Average reading is a true mathematical time-averaged reading of about the last 1000 samples. This gives the correct reading for DECT and WiFi and is much lower (DECT average power is about 0.01 of the DECT pulse power) than many other instruments which use the highest peak reading and then translate that into an equivalent average power. That is not correct as power is measured as total energy used/delivered per second and not the energy in a short pulse of say 10 milliseconds followed by a 990 ms gap. It is important that we understand this as most international standards are based on true average power (actually usually averaged over 6 minutes!).
N.B. The internal antenna is at the top rear of the case. Signals are best measured when the source is behind the instrument, but also quite good with the source to one or other side (particularly the left side away from the switches and volume control). It under-reads if the source is in front of the meter as the LCD display acts as an RF screen.