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If the new frequency is out of the range admissible for the amplifier (S. 8-1(a)), the transmission request is denied
and the following fault message appears on the screen:
“FREQUENCY OUT OF RANGE”
The standard frequency bands within which all amplifier parameters are guaranteed are listed in S. 8-1(a)).
Extension or changes of the bands could be negotiated with the manufacturer.
4-3.
Change of antennas and operation with an external antenna tuner
At a band change or moving frequency from one to the other end of the band it may be necessary that you change
the antenna and eventually retune the antenna tuner (unless your antenna is a multibander and / or is broadband
enough).
At antenna SWR over 1.5:1, it is preferable that you use an external tuner. Usually the procedure for retuning the
tuner requires a continuous carrier signal and small power. In such a case, go to the STBY mode of the amplifier
and feed the power necessary for tuning from the transceiver only. After you have retuned the antenna tuner on
the new operating frequency or with the new antenna, return to the Operate mode and adjust again the drive
power according to the operating mode used – S. 3-6(f)).
4-4. Cooling and fans operation; modes with increased heat loading
During operation in modes with increased heat loading (continuous carrier, RTTY, SSTV, some digital modes, and
others), the amplifier itself will monitor its temperature regime, automatically increasing or decreasing fans velocity
depending on the loading and ambient conditions (temperature, humidity, atmospheric pressure etc.).
4-5.
Monitoring the amplifier operating regime
Because of the availability of a continuously operating protection system in the amplifier (S. 4-6), the operator is
not required to monitor its regime regularly. However, whenever he wishes, he can digitally measure the 11 most
important parameters connected with the amplifier operating regime. Besides this, the operator can select two of
them arbitrarily for indication also in the basic screen (Fig. 3-2, S. 5-1).
4-6.
Automatic protection system
The control unit (S. 7-3(b)) keeps track with most amplifier analogue and logic signals in all modes. Monitored are,
for example, the control signal receive / transmit, the output relay contact status and switching times, the RF drive
frequency and drive power (the input power), the DC current and the DC voltage on the drains of the final
transistors, the bias voltage of their gates and the temperature of their heat sink, the temperature of the main
components in the power supply unit, the forward and reflected power at the RF output, and others. Besides this,
monitored and assessed are some derivative parameters, such as the power gain, the SWR, the heat power
dissipated by the final transistors dynamically etc.
If anything abnormal has been found out in an arbitrary moment, the amplifier will assess the risk of the situation
and can use three levels of protection according to the problem nature and seriousness, as described in items (a)
to (c) below. Every event is accompanied by a warning text on the screen (Fig. 4-1), which is blinking to attract the
operator’s attention. Besides this, a sound signal is produced, whose volume, can be reduced by the operator if he
so wishes – menu “USER PREFERENCES” – Fig. 5-4.