User’s manual EXPERT 1K-FA
Pag. 28 of 76
11.2 Operating
You need few precautions when using the amplifier thanks its high level of automation.
SPE reminds you that it is better to lose a fraction of dB in transmitted power, by slightly
reducing the drive power, than to over-drive the amplifier and have a poor quality
transmission.
During transmission check the parameters on the display always, because SPE has
selected, designed and adjusted them with care.
SPE recommends (using the ALC link) that the transceiver should be set to its
maximum drive power.
To reduce the amplifier output, if required, it is then necessary only to set the amplifier
to “HALF” power state rather than changing the transceiver drive power.
Of course you may also regulate continuously the amplifier output power by changing
the level of drive power from your transceiver.
If less output power than 500 Watts is desired, it is preferable, for best efficiency, to
start to reduce drive from the “HALF” 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. Check the
“PW REV”. If it shows more than 120/140 Watts, decrease the power of
the transceiver until that value or less is noted.
When CW mode is extensively used, a
manual regulation of the exciter’s
output power is advisable to avoid improper ALC action if the transceiver
has an excessively slow ALC regulation. Poor ALC regulation could result
in overdrive, which in turn could result in damage.
c) RTTY, DIGITAL MODES, SSTV, FM: SPE recommends you operate in ‘HALF’ mode
because these types of transmission have a very high duty cycle. Check
“PW REV”, and if it shows more than 120/140 Watts, decrease the power
from the transceiver. In case of very heavy use, it is advisable to work in
“Contest” condition to take advantage of the greater efficiency of the fans.
d) AM This transmission mode radiates a continuous carrier which is 25 % of its
PEP value (400W PEP AM = 100W carrier power). SPE recommends you
always operate in ‘HALF’ 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, and no modulation. Set the
transceiver without exceeding 125W of 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 500W. Note that because of the
modulation characteristics of AM, the average value shown will normally
To Next Page
Loading...
