User's Manual

KAIROS User Manual - version 1.3
Radio Activity S.r.l. 12/11/2014 29 / 41
2. The transmitter might generate spurious radiations.
3. The transmitter might increase its floor noise; this can produce de-sensitivity on the receiver
path.
4. The transmitter output power might become erratic, either too high or too low as measured on
a wattmeter.
In case of a poor branching system, the use of a ferrite isolator at the output of the transmitter
should solve the reflected power problem.
∞ RX sensitivity; since KAIROS is a digital transceiver, the sensitivity should be measured in digital.
Anyway, considering that the digital demodulation is only a SW algorithm, it is enough to measure
the sensitivity in analog. The sensitivity should be measured on both channels, Main and Diversity,
with the branching filters. The S/N should be better than 20dB with a RF field of -110dBm
@12.5KHz of channelization.
∞ RX de-sensitivity; this measure verify the RF pollution that influences the antenna. Connect the RX
input to the antenna inserting a directional coupler. The sensitivity measured with the antenna and
substituting it with a dummy load should differ for few dB (typical value: 2-6 dB @160MHz, 1-3dB
@450MHz). If the measured value is not satisfactory, you can try to insert a band pass cavity filter.
∞ RX de-sensitivity when the TX is on; this measure verify the correct isolation of the TX/RX filter
system. Connect the antenna input to a duplex test set analyzer. The sensitivity with the TX on
respect when off, should differ for less than 3 dB (this value may vary with the TX/RX band
separation). ). If the measured value is not satisfactory, the TX/RX isolation of the branching filter
should be increased; the problem may be also in the noise of the power supply when the
equipment is in TX.
∞ Verify the IP network functionality (if the equipment is a part of a network); if the Master station is
present, a KAIROS slave should register itself to the master within 1 minute. The led “NETWORK” in
the frontal panel should blink green. Verify all the signal path: a signal received locally must arrive
to the Master (see its voter mask), must be selected in the master and must be transmitted locally.
Be sure that the signal re-transmitted is effectively the signal coming from the Master and not a
local copy.
∞ At the end remember to save on your PC all configuration parameters of the base station; these
parameters can be very useful to clone a substituting unit in case of fail.
4.10 IP discover
When KAIROS is placed in field or coming back from a site, maybe a problem to connect to it if the IP
address is unknown. A simple way to discover the IP is switching on KAIROS with the following procedure.
1. Switch off the equipment