INDEX Page. 24 of 92
6. ANTENNA
Because this is a high-power amplifier, it is necessary to use properly rated antennas,
connectors and feed line cables.
Much care must be paid to the use of antennas with traps, BALUNs and impedance
transformers insufficient so that often, after continuous use at high power, these elements
exceed the Curie temperature degenerating irreversibly, resulting in a dangerous increase
in SWR during each transmission which could lead the linear to damage.
This dangerous situation is often not perceived by the operator because a normal measure
of SWR is made when a balun and antenna are not under stress or have cooled down.
Ensure that your baluns, impedance transformers or traps are appropriately rated !
A unique feature of this linear is that, measurements are made not only of the SWR after
the band pass filter matching, but also of the SWR of the system antenna and cable. This
allows the operator to always evaluate their antenna system despite the matching and the
power applied.
With the internal ATU, the amplifier is able to overcome mismatches up to 5:1 at full
power.
Be aware that, with the tuner, the PA is matched but with a high VSWR the cable is
mismatched and there can be consequent loss of power, heating and high voltages
present, therefore always try to use resonant antennas, avoiding non-resonant antennas if
possible for the reasons explained previously (insufficient impedance transformers).
Always operate with the best possible matching because, despite the amplifier’s protection
against high SWR, continuous use into a mismatched load (a bit lower than the protection
threshold) may lead to damage.
In the case of repeated "SWR EXCEEDING LIMITS" alarms while being protected,
the amplifier is still exposed to risk.
If you persist without investigating the causes, thus causing a failure, you will lose
the warranty.
It is suggested that suitable static protection be given to antenna feeder cables.
The software allows you to select up to two antennas for the same band.
Note: For a mismatch from 1.7:1 to 2:1 there is an alarm, above 2:1 the amplifier is switched to
STANDBY.
For setting, see chapter 10 "Programming", refer to the “ANTENNA” item on the main
menu.
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