User manual

ManualsBrandsGIGAHERTZ SOLUTIONS ManualsRadiation MeasurementHF 38B High frequency (HF)-Analyser, Electric smog meter, 800 - 2500 MHz (3300 MHz/-3 dB), includes

Digitaler Hochfrequenz Analyser HF38B

cially in the near range), the value itself has

no meaning.

Polarization

When RF radiation is put on the airwaves, it

is sent off with a „polarization.“ In short, the

electromagnetic waves propagate either ver-

tically or horizontally. Cellular phone technol-

ogy, which is of greatest interest to us, is

usually vertically polarized. In urban areas,

however, it sometimes is already so highly

deflected that it runs almost horizontally or at

a 45-degree angle. Due to reflection effects

and the many possibilities a cellular handset

can be held, we also observe even other po-

larization patterns. Therefore it is highly rec-

ommended to always measure both polariza-

tion planes, defined by the orientation of the

antenna.

Fluctuations with Regards to Space and

Time

Due to reflection, also depending on the

respective frequencies involved, amplification

or cancellation effects can occur in certain

spots, especially within houses. Furthermore

most transmitters or cellular handsets emit

different amounts of energy during a given

day or over longer periods of time because

reception conditions and network usage

change constantly.

All the above-mentioned factors affect the

measurement technology, especially the

testing protocol, which is why in most cases

several testing sessions become necessary.

Introduction

to RF Measurement Tech-

nology

The supplied, logarithmic-periodic antenna

has an exceptional directionality. Thus it

becomes possible to reliably locate or „tar-

get“ specific emission sources in order to

determine their contribution to the total RF

radiation level. To know exactly the direction

from where a given RF radiation source origi-

nates is a fundamental prerequisite for effec-

tive shielding. The missing directionality of

standard telescope antennae is one of the

reasons, why they are not suited for reliable

RF measurements in building biology EMR

surveys.

The values shown on the display always re-

flect the power density of the ambient levels

in reference to the spatial integral of the „an-

tenna lobe„, that is to the direction the an-

tenna is pointing towards. In addition to ave-

rage measurements, this RF analyzer also

offers an particularly important technical

specification: true peak measurements.

With regards to pulse-modulated RF radiati-

on not only the average value is calculated,

but the total maximum value of each single

pulse can be detected. In the case of a 2.4-

GHz cordless phone base station, the peak

value can be 100 times higher than the ave-

rage value.

The frequency range of this RF analyzer co-

vers cellular phone frequencies (e.g.

GSM800, GSM1900, TDMA, CDMA, AMPS,

iDEN), 2.4-GHz cordless phones, frequencies

of third generation technologies such as

UMTS, WLAN based on bluetooth as well as

other commercial frequency bands and mic-

rowave ovens. All the frequencies inbetween

are of course also included. This is the fre-

quency range within which you find the pul-

se-modulated signals concerned scientists

are most worried about.

In the vicinity of radio and TV towers, major

transmitters as well as strong private sta-

tions, the RF radiation levels of those lower

frequencies can also be the cause of major

exposures. From a technical point of view,

the use of low-cost telescope antennae to

measure their power density levels has to be

looked at with a critical eye. For those lower

frequency bands, Please ask us for specific

solutions for those lower frequencies sup-

plied by GIGAHERTZ SOLUTIONS.

A Special Case: Radar

For air and sea navigation a radar antenna

slowly rotates around its own axis, thereby

emitting a tightly bundled „radar ray“. Even at

a sufficient signal strength, this ray can

therefore only be detected every couple of

seconds for a few milliseconds, which re-

quires a special measurement technology.

Due to the rectifier circuit we use, weak

radar

signals are slightly underrated. We approve

of this fact because for this price range our

circuit design offers a pioneering high sensi-

tivity level for all continuous as well as con-

tinuously pulsed signals (from GSM to 2.4

GHz).

Important Note: Because of the longer signal

duration at shorter distances from an RF

source as especially found in stronger radar

signals, this quite slight underrating will then

even be considerably less of an inconven-

ience.