Comparison between antenna amplifiers
512F (China), Microampl. (Triax, DK) and DIGI-YAGI 16 U (Iskra, Slo)
04 / 11 / 2010
512 F
(China)
Technical Specification :
DIGI-YAGI 16 U
(Iskra)
Microamplifier
No. 340012 (TRIAX)
Number of inputs
1
1
1
Frequency range
40 - 862 MHz
470 - 862 MHz
470 - 862 MHz
Gain
14 - 18 dB
16 dB
12 dB
Noise figure
3.0 dB
2.0 dB
2.3 dB
Number of outputs
1
1
1
Max. output voltage 60 dB, IMA
90 dBµV
98 dBµV
95 dBµV
RF shielding
Yes
Yes
Yes
Notch filters for GSM and TETRA fr.
No
Yes
No
Power consumption
24 mA
22 mA
10 - 22 mA
Power supply
5 - 12 V DC
5 - 24 V DC
5 - 12 V DC
Connector
F connector
F connector
F connector
Dimensions L x H x W (mm)
80 x 25 x 17
44 x 30 x 27
47 x 20.5Ø
Sources of interferences (short explanation):
• FM – UKW Radio : Radio Transmitters usually have (very) strong signals. They are
working on following frequencies: 76 ~ 84 MHz (OIRT) and 88 ~ 108 MHz (CCIR).
• TETRA : Emergency Services : 380 ~ 430 MHz band for public safety users.
• EX. NMT : Several countries still use ex. NMT freq. band for Wireless Internet
communications on: 430 ~ 450 MHz
• GSM 900 : Downlink frequencies ( 925 ~ 960 MHz = E + P band )
For undisturbed reception of TV signals, filters need to cut all mentioned
frequencies!
All Iskra’s amplifiers have notch filters for TETRA 400, GSM 900, FM and 1,1 GHz frequencies.
Joco Lazić, e-mail: jovan.lazic@iskra-tela.si
The importance and usefulness of
notch filters in antenna amplifier
Antenna amplifiers built–in balun or in LOG antennas (Iskra)
DIGI-YAGI 16 U / DIGI-LOG 15R SWITCH SYSTEM …
9 / 2010
Real life situation :
←
Klagenfurt, Austria
Sources of interferences:
• TETRA. UK Emergency Services : The
British Home Office has chosen TETRA as a
communications system for emergency
services including police, fire and
ambulance. Within Europe and the UK,
these services will operate in the 380 ~
400 MHz band for public safety users.
• EX. NMT : Several country use ex. NMT
freq. band for Wireless Internet
communications on: 430 ~ 450 MHz
• GSM 900 : Downlink frequencies (925 ~
960 MHz – ext. band) are strong and very
close to TV channels.
• For undisturbed reception of TV signals,
filters need to cut all mentioned
frequencies!
Band
Measured
Signal Levels
( dBµV )
1
TETRA 400
2
3
4
GSM 900
Amplified signal levels ( dBµV )
Amplifiers - With notch filters
DIGI-YAGI 16 U (Iskra)
DIGI-LOG SWITCH (Iskra)
Amplifier
Without notch filters
( Es. AM 8000 Engel )
85
79
! 103 !
UHF 1
45
61
59
UHF 2
68
84
82
104
99
! 120 !
Important ! All Iskra’s amplifiers have notch filters for TETRA 400, GSM 900 and 1,1 GHz frequencies.
DIGI - YAGI 16 U
DIGI-LOG 15 R – U
SWITCH SYSTEM
Interferences are consequence
of non cutting strong
TETRA and GSM signals
( more than 100 dBµV )
in antenna amplifier
Interferences on analogue TV signal
Interferences on digital TV signal (freezing)