Seite 6
ROM-Elektronik GmbH
over the antenna. Do not be surprised when you hear the signals for the first
time. Here you get an impression that signals are in the "ether" that you do
not notice because none of your senses is able to register these.
A signal which is simple to identify is that of a DECT cordless telephone. The
base station constantly sends a 100 Hz tone whether telephoning or not! As
soon as the power plug is pulled on the base station, the hum tone disap-
pears.
Mobile telephones (cells), which communicate according to the GSM
standard, send a 217 Hz signal. However, this is sent only during telephon-
ing. The corresponding base stations, on the other hand, can be identified
through a high whistling tone with approx. 1733 Hz (8x217 Hz =1733 Hz).
Radar systems send signals from 600 Hz to 1200 Hz.
There are innumerable other, in-part "exotic" signals, which cannot all be
counted here. With time, you will gain your own experience.
Functions
The HFA-3 has a built-in filter bank in order to carry out the measurement for
individual frequency ranges only. The filters are set adjusted to fixed fre-
quencies. In the measurable frequency range, the 3 bands of the mobile
communications are offered (GSM900, GSM1800, 3G (UMTS)), cordless te-
lephones (DECT) and the services employed for computer networking,
such as WLAN and Bluetooth.
The pushbuttons located on the front side are employed to alternate bet-
Frequency designation
Frequenzbereich
All-pass network (no filter)
10 MHz to approx. 2500 MHz
GSM900
935 MHz to 960 MHz
GSM1800
1805 MHz to 1880 MHz
DECT (Digital Enhanced Cordless Telephone)
1880 MHz to 1890 MHz
3G (UMTS)
2110 MHz to 2170 MHz
WLAN, Bluetooth, Mikrowellenherde
2400 MHz to 2500 MHz
Designation and frequency range of the frequency filter of the HFA-3
Situation of the frequency filters on the HFA-3
Seite 47
ROM-Elektronik GmbH
After a click on OK, the first data can be sent to the PC.
If everything has proceeded successfully, data should now appear conti-
nuously on the screen in similar form as represented above. If a filter is selec-
ted, this is output behind the measured value.
Select 2400 baud, 8 databits, 1 stopbit, no parity
Data output of the HFA-3
