User manual
EXPERT 2K-FA
Pag. 31 of 31 Issue 2 – May 2011
Of course you may also regulate continuously the amplifier output power by changing
the level of drive power from your transceiver (also with the ALC connected).
If less output power than 2KW, 1KW or 500 Watts is desired, it is preferable, for best
efficiency, to start to reduce drive from “MAX”, “MID” or “LOW” power state.
Setting Drive Levels
a) SSB: Regulate the “MIC GAIN” of the transceiver until, speaking normally into
the microphone, the signal peaks on the display don't quite reach the
maximum rated output power. Monitoring the transmission is a good way
of checking your settings. If there is however some distortion, decrease the
“mic. gain” or decrease the power of the transceiver until a small reduction
of the output power of the amplifier is seen.
b) CW:
In key down, you get the maximum output power automatically.
c) RTTY, Digital modes, SSTV, FM: Because all of these types of transmissions have
a very heavy duty cycle, you should not operate in 'MAX' but only in "MID"
and "LOW ".
An appropriate SW ensures this requirement.
d) AM: This transmission mode radiates a continuous carrier which is 25% of its
PEP value (e.g. 400W PEP AM = 100W carrier power). SPE recommends
you always operate in ‘MID’ or “LOW” mode for AM.
To get an output signal without distortion, proceed as follows:
transmit the AM carrier only, with your transceiver “MIC GAIN” set to zero,
set the transceiver without exceeding 25% of the maximum carrier output
from the amplifier.
Then, speaking into the microphone normally, set the” MIC GAIN” of the
transceiver until the peak output power, on speech peaks, as shown on the
amplifier display, is no more than 1 KW or 500W. SPE suggests you
monitor your transmission to check that the “MIC GAIN” setting is correct.
Note:
if you choose to set the output power of the amplifier by varying the output power of
the transceiver, the ALC connection is not strictly required.
In this case
you
must be careful not to overdrive the amplifier to avoid distortion
and broadening of the channel (with the ALC, adjustment is automatic for
maximum linearity and Pout).
All functionalities remain the same protections included, the only feature that is
less is the return to full power to the transceiver when it returns to STANDBY.
Note: ATTENTION
,
never stress the amplifier with long periods in key-down transmission, as
this can stress the amplifier components. An appropriate SW
avoids transmitting a
continuous signal in the "MAX" condition for a long time by switching to "MID".
Note:
in SSB use a compressor only when necessary; this strongly reduces the temperature
increase.