Quick Installation Guide
Document
WERA4-Quick-US-200917
Page 40 of 73
If one voltage is higher, check if the PA is really operating with lowest gain. If the power
need to be further reduced, connect a 20 dB N-attenuator (enclosed in the tool box) at the
input of the PA
and run the test again.
Now the voltage must be smaller than 7 volts but maybe now it is lower than 1 volts. In that
case you may need to increase the gain of the PA (1 step of the knob to the right is +3
dB).
The voltage level for the Rx antenna that is closest to the Tx should have the highest
signal. The le
vel should decrease with increasing distance to Tx. If there is a strong “jump”
in the signals level behaviour, something with the Rx array is not normal (cable, VSWR,
resonance, strong reflections, dunes). If the reason might be environmental conditions, this
effect can be accepted. Mismatching or wrong tuning needs to be corrected.
If the voltage is correct, keep this setting and write down the
rms voltage
of that antenna
closed to the Tx array in the “Installation Check List”.
Now Start a
Single Acquisition
, don’t forget to set the frequency offset to 0Hz
512 samples, 0.260 sec sweep, no frequency offset
Check the results using “Plott_WERA_Sort_RCs_Beam_rfi
”
according to the description
in pos. 11.5.
From the Range Doppler plot the range can be estimated. Please write down this
estimated range at 0° in the “Installation Check List”.
After these first tests with a single Tx antenna (with an omni-directional beam pattern) the
remaining Tx antennas need to be installed and tuned, see chapter 5.6
Important: Because the 4 Tx antennas are located quite close to each other, the individual
characteristic is affected by their neighbours. For that reason please carefully follow these
instructions:
Mount all antennas and connect all cables. Layout all cables in their final position. The
cables should not be moved again. The cable layout should be similar to the sketch below.
Ocean this direction
The cables should be laid out as sketched. The coax cables should run in parallel with the radials
and the left over coax cable should be placed as coil next to the 1:4 splitter which is placed behind
the array. The splitter can be buried in the ground.
1:4 Splitter
Radials
Antennas
Long
Phase
cable
Long
Phase
cable
short
Phase
cable
short
Phase
cable
Tx cable
