User Manual

Axell Wireless Limited
Technical Literature
L.A. M.T.A. Remote Sites
Document Number 80-301401HBKM Issue No. 1 Date 13/06/2008 Page 102 of 148
4.9.5.1. Bandpass Filter (01-002503)
The bandpass filters are multi-section designs with a bandwidth dependent upon the passband
frequencies, (both tuned to customer requirements). The response shape is basically Chebyshev with
a passband design ripple of 0.1dB. The filters are of helical design, and are carefully aligned during
manufacture in order to optimise the insertion loss, VSWR and intermodulation characteristics of the
unit. The tuned elements are silver-plated to reduce surface ohmic losses and maintain a good VSWR
figure and 50ȍ load at the input and output ports.
Being passive devices, the bandpass filters have an extremely long operational life and require no
maintenance. Should a filter be suspect, it is usually most time efficient to replace the module rather
than attempt repair or re-tuning. No adjustments should be attempted without full network sweep
analysis facilities to monitor both insertion loss and VSWR simultaneously.
01-002503 Specification
SPECIFICATION PARAMETER
Downlink 154.0 MHz to 161.5 MHz
Bandpass
Frequency
Uplink 155.5 MHz to 161.0 MHz
Downlink 7.5MHz
Bandwidth
Uplink 5.5MHz
No. of sections 6
Insertion loss 1.2dB
VSWR Better than 1.2:1
Connectors SMA
Power handling 100W maximum
operational -20°C to +60°C Temperature
range
store -40°C to +70°C
Weight 3 kg
Size 384 x 82.5 x 56.4mm
4.9.5.2. Switched Attenuator 0.25Watt, 0 - 30dB (10-000701)
10-000701 provides attenuation from 0 to 30dB in 2 dB steps The attenuation is simply set using the
four miniature toggle switches on the top of each unit. Each switch is clearly marked with the
attenuation it provides, and the total attenuation in line is the sum of the values switched in. They are
designed to maintain an accurate 50ȍ impedance over their operating frequency at both input and
output.
10-000701 Specification
PARAMETER SPECIFICATION
Attenuation Values 0-30dB
Attenuation Steps 2, 4, 8 and 16dB
Power Handling 0.25 Watt
Attenuation Accuracy ± 1.0 dB
Frequency Range DC to 1GHz
Impedance 50ȍ
Connectors SMA
VSWR 1.3:1
Weight 0.2kg
operation -20°C to +60°C Temperature
range
storage -40°C to +70°C