4
BASIC OPERATION OF THE AMPLIFIER
4.1
Applying The Mains Supply
Before applying the mains supply to the amplifier, the operator must be satisfied that:
*
both the RF input and RF output connections are correctly terminated (see
section 3.2),
*
safety and cooling requirements are complied with (see safety notes and section
3.3),
*
the correct type of mains cable is in use (see section 3.4).
Once the above has been verified apply the mains supply to the amplifier. The fans
will be heard to start.
It is good practice to allow the TWT to cool for three to four minutes after leaving the
transmit mode, before disconnecting the amplifier from the mains supply.
4.2
Mains Supply Interruptions
It is common on some mains or local generator derived supplies, for the supply to be
temporarily interrupted. This section details the behaviour of the amplifier under
these conditions when it is transmitting.
Interrupt
5
30 ms - the amplifier will continue to operate normally.
Interrupt
4
30 ms
5
5 seconds - a degradation of RF performance can be expected,
the amplifier will leave the XMIT mode. When the mains supply returns, the amplifier
will automatically re-enter the XMIT mode within 1 second. All operating parameters
will be as previously set.
Interrupt
4
5 seconds - a degradation of RF performance can be expected, the
amplifier will leave the XMIT mode. When the mains supply returns, the amplifier will
remain in the OFF mode until the user selects another mode of operation either
manually or automatically.
4.3
Functions
As the amplifier has no direct human interface for control or monitoring, the 41-pin
control connector is used to effect control either via the serial communications bus or
the discrete control connections.
This section describes the control functions available to the user.
4.3.1
Amplifier OFF mode
Applying prime power to the unit results in the amplifier entering the OFF mode until
another mode is selected. In this mode, only the Amplifier control, auxiliary circuits
and fans are operational, the main cooling fan operating at half speed.
Following transmission, the OFF mode can be requested to remove the amplifier from
the XMIT mode.
HBN63xx-1, Issue 8, Page 17
