INTRODUCTION
Thanks for the preference granted us in the purchase of our solid state HF/VHF linear amplifier
model HVLA700AY (in succession called amplifier). The professional construction, the use of selected and
oversized components and the technical solutions adopted make it a high quality product, accurate and reliable
during the time. We recommend a suitable use of this amplifier and only for high distance links.
Finally, we advise to read this manual before operating this equipment.
GENERAL DESCRIPTION
The amplifier covers all amatorial bands from 1.5MHz to 55MHz and all operative modes. Its peculiarities can be
summed up in: immediate operativity, no tuning operations, low consumption, quitness and reduced weight. It
can be automatically controlled by any type of YAESU and ELECRAFT transceiver equipped with “BCD DATA”
output. The absence of a software does not reduce the quality of the amplifier, on the contrary, it protects it
from all the problems due to the software time response, however short they are, are sometimes source of
serious damage.
It is composed by these circuits:
-Activ input match/attenuator able to match perfectly the output impedance of the transceiver with the
input impedance of the amplifier and to protect, in a very effective way, the amps in case you exceed the drive
power.
-Power amplifier stage push-pull AB class type composed by 4 X VRF151 RF Power Vertical Mosfet chosen
for their robustness, resistant to high impedance mismatches and low Intermodulation Distortion (IMD).
-Output filters it is the only amplifier, built with high quality components planned for having an high
suppression of the unwanted emissions (harmonics and spurios).
-ALC circuit essential for reduce the drive power level in the case the output power of the amplifier get to
values that produce distortion. It works also when we are in the presence of an excessive level of antenna
SWR.
-Protections that, thanks to the high quality of the “directional couplers” used, protect the amplifier in case of
wrong change of the filter band, excessive VSWR, open antenna and short circuit antenna. The temperature
sensors preserve the RF power Mosfet from excessive thermic stress and “shift” in the working class of the
amplifier.
-Power supply of switching type, oversized, no “noise” and equipped with “Power Factor Corrector” circuit
according to the new European Rules on energetic efficiency.
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