Some words about GSM-antennas:


At first: a long antenna is the result of a low frequency. An antenna for 145 MHz is longer
than an antenna for 900 MHz.

The lenght of an antenna can be different at the same frequency. This depends on the gain
(dB) of it.

Gain-antennas are mostly shorter than they have to be naturally because they contain hidden coils.
Because of this you can use GSM-900 0-dB-antennas for GSM-1800, but not 3-dB-antennas !

The highest mounting-point is the best mounting-point for the antenna. Groundplane
(car) antennas must be mounted vertically. Otherwise they cannot send the whole signal
horizontally about wide ranges. And they do not receive signals very good !


Loss of signal is growing with the lenght of the cable. So it ist useful to use cable with the
exactly needed lenght.

Example:
Signal-loss/m 450 MHz 900 MHz 1800 MHz
LowLoss RG 58 (ca. 5.5 mm diam.) 0.23 dB 0.35 dB 0.54 dB
RG 58 (ca. 5.5 mm diam.) 0.33 dB 0.49 dB 0.73 dB
RG 174 (ca. 3 mm diam.) 0.7 dB 1 dB 1.5 dB

The cable with the less signal-loss is the best one (here LL-Rg 58) !
Much less signal-loss you can get with RG 213 or so called Aircell 7.
But you can get problems with the correct connectors.


Frequencies:
NMT-450 453-467 MHz
GSM-900 880-960 MHz
GSM-1800 1710-1880 MHz
GSM-1900 1850-1990 MHz



smiline.gif

back.gif back to the antenna page

back.gif back to my AEG/GSM page

back.gif back to my homepage

© by Dirk Salva