Use and maintenance manual
Page 39
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E-Mail: support@elenos.com
3. USER INSTRUCTIONS
3.5.
Checking performance
Power developed Connect a high quality wattmeter (e.g. Bird mod. 43) to the unit, via a double, male
N-type connector. The wattmeter output is connected to a high quality dummy load (SWR
less than 1.05) capable of dissipating at least 500W continuously via a 50 Ohm coaxial
cable of appropriate cross section (e.g. RG213). Adjust the maximum range of the watt-
meter to correspond to the power generated (e.g. for a Bird mod. 43 wattmeter, use a
500W probe adjusted to measure direct power). Power up the unit and check that the
power shown on the display corresponds to the power displayed by the wattmeter. There
is a tolerance of upto 25W difference between the two.
It is of the utmost importance to use a wattmeter that is performing to its high precision
specification.
The measurement will be invalid if the wattmeter is connected to the unit via a coaxial
cable without the double connector as specified.
Connect the unit to a dummy load with a -30dB output capable of dissipating at least
500W of continuous power, via a 50 Ohm coaxial cable of appropriate section (e.g.
RG213). Connect the output of the dummy load, attenuted by another 20dB, to a fre-
quency meter which is known to be performing to its high-precision specification. Power
up the unit and check that the frequency shown on the display corresponds to the fre-
quency displayed by the frequency meter. There is a tolerance of upto 100Hz difference
between the two readings.
Connect the unit to a dummy load with a -30dB output capable of dissipating at least
500W of continuous power, with a coaxial cable of appropriate section (e.g. RG213).
Connect the output of the dummy load, attenuated by another 20dB to a modulation
analyser which is known to be performing to its high-precision specification. Connect the
MPX input to a 1KHz sinusoidal signal from a low-frequency signal generator, with the
amplitude adjusted for a level of 0dBm. Power up the unit and check that the deviation
displayed by the unit and by the modulation analyser fall within the range 75KHz -0.2dB
and 75 KHz.
Programmed frequency
Deviation
This procedure for checking performance should be carried out if there is any
doubt over the integrity of the unit or possible damage sustained during transport. It
should be performed by expert personnel capable of operating radiofrequency measure-
ment equipment.
The unit is calibrated using an FMAB modulation analyser (R&S) and so the per-
formance checking equipment must be high precision, analogue instrumentation.
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