R.V.R. Elettronica PJRL250, Техническое руководство

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PJRL250 Technical and Maintenance Manual
R.V.R. Elettronica S.r.l. (Bo) Pag. 31
6) Slowly increase the drive power to obtain 250W of output power.
7) Check with a spectrum analyzer connected to a suitable directional
coupler (e.g. the BIRD tap) that the harmonics level is be -75dB.
8) Adjust the trimpot TR1 in the L.P. Filter until you obtain a slight
output power drop in the PJRL250 amplifier. This power drop tells
us that the power limit system is acting.
9) Now increase again the drive until "V" decrease and you obtain a
lock condition of the amplifier due to the Overdrive Protection;
this protection is adjustable by means of trimpot R26 on the Alarms
Card.
This protection must come on when "V" voltage is at about 48VDC.
10) Verify that for an output power of 250W the readings on the internal
wattmeter (9 Fig.1) and the external wattmeter coincide (if not,
adjust R11 on the Alarms Card).
11) ANTENNA S.W.R. CALIBRATION
11A) Reduce the drive power to the minimum value, switch off the amplifier
and the exciter.
11B) Connect two paralleled 50Ohm P>300W dummy loads to the RF OUTPUT
connector of the amplifier as in schematic SETUP4 (Fig.7).
11C) Switch on the amplifier and the driver and wait for the PLL to lock.
11D) Select REF with the meter selector, and set the external wattmeter
for reflected power reading.
11E) Increase the output power to obtain a reading of 25W REF on the
external wattmeter. Now adjust trimpot R13 on the ALARMS CARD to
obtain the same reading on the PJRL250 meter.
11F) Increase again the power, until you read 30W of reflected power,
adjust R56 on the Alarms Card (remove the metallic shield that covers
the alarm cards) until the SWR ANTENNA protection acts.
SETUP 4 / FIG. 7