HELZEL Messtechnik WERA User manual

Tune –up Instructions
Document
WERA4-Tune-up-Instruction-200919
Page 1 of 4
Tune –up Instructions
Version 1.0 September 2020
HELZEL Messtechnik GmbH
Carl-Benz-Strasse 9
24568 Kaltenkirchen, Germany
www.helzel.com
e-mail: [e-mail]
Tel.: [phone] - 95 20 –0
Fax: + 49 (0) 4191 - 95 20 –40

Tune –up Instructions
Document
WERA4-Tune-up-Instruction-200919
Page 2 of 4
1. Calculate the maximum permitted output power of the power amplifier
The radiated HF power must be kept below the defined maximum radiation power
for Ocean Radar of 50 WERIP (47 dBm).
Please note that the WERA power amplifier is capable to provide up to 49 dBm to
compensate for cable losses for cases with the Tx antenna system installed in a
distance of several 100 Meters.
The maximum permitted output power for a specific installation can be calculated:
max PA output level = max radiation –antenna gain + cable loss
If the radiation can’t be measured in the field, the antenna gain should be assumed
as best case which is 6 dB.
The cable loss depends on the cable length and the attenuation of the used cable
type. Please contact the manufacturer to get the according value for your site
specific set-up.
2. Adjust the output power of the power amplifier
The output power can be set in steps of 3 dB and must always be adjusted to be
below the calculated permitted radiation level.
The output power of the power amplifier, see picture below (Fig. 1), is normally
adjusted via remote control. If for any reason the remote control is not available the
power can be adjusted manually by means of the black knob at the front. This
manual setting is accessible when removing the plastic cover at the front.
Figure 1: Power Amplifier

Tune –up Instructions
Document
WERA4-Tune-up-Instruction-200919
Page 3 of 4
Please ensure that the Tx antennas are tuned correctly and all cables are
connected.
It is strongly recommended to start the tune-up procedure with lowest output power.
The output power can be adjusted manually or via remote access. The remote
access is the preferred option. It accessible via the “Remote Control” program, the
window below (Fig. 2) will show up and gives the user access to the settings and
displays the measured values.
Figure 2: Remote Control Interface
Please click on “Settings” to access the “PA” window, see figure 3.
Figure 3: PA setup window
Forward Power
Reflected Power

Tune –up Instructions
Document
WERA4-Tune-up-Instruction-200919
Page 4 of 4
As a first step the output power need to be adjusted to a minimum, that means the
PA gain should be set to 20 dB. Click on “Submit” and “save + close” to active the
setting and return to the initial window (fig. 2).
-Now run a short calibration measurement (80 Hz frequency offset).
-Click on “check system now” to get the power amplifier output power reading.
-Check the results using “Plott_WERA_Cal_lsq” according to the description of
chapter 11.7 of the Quick Installation Guide.
-All “rms voltages” are expected to be below 7 Volts
-Increase the gain by one step using the PA setting window and run a calibration
again.
Attention: Always check the output power value to ensure that the
level is kept below the calculated max PA output power limit.
-If no antenna has reached the 7 volts limit the gain (=power) can be increased by
one step again.
The optimum is reached as soon as one Rx antenna
voltages reaches a value close to the 7 Volts limit.
-If this optimum output power is more than 4 dB lower as the calculated max PA
output power, the receiver sensitivity can be reduced, please refer to chapter 7.1.5
of the Quick Installation Guide.
-After increasing the “Receiver Attenuation” by 4 dB the power can be increased by
another step and the output power and the rms voltages should be checked again.
This procedure can be repeated until the Receiver Attenuation reached a
value of 12 dB.
Attention: Always check that at the PA no red LED is on.
In that case reset the PA before the next calibration cycle is started.