Asymod BT-HPSA V2, Instruction Manual

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The HPSA V2 allows the operator to compensate for the high and low frequency rolloffs
of typical AM receivers when using an equalizer to provide high and low frequency
boost to produce the required pre-emphasis that is appropriate for very narrow-band
receivers. Using a parametric low and mid frequency equalizer allow
you to tailor your
air
sound and rolloff to your precise requirements and desires. On board passive and
active selectable low pass filters provide preset rolloff points that can adjusted by
changing the filters’ capacitor values.

The HPSA V2 can deliver up to 300W of audio modulator power sufficient to drive a
100W+ PA. The modulator stage provides 12 volts to the transceiver RF final stage when
in other modes other than AM thus allowing the transceiver to be typically operated
from a ~1 amp supply.

The HPSA V2 is a station monitor that provides the operator functional simplicity by
providing the operator the ability to monitor, mix, record and playback the transmit and
receive audio.

LED indicators show power on, mode selected, audio peaks and TX.

The HPSA V2 is a self-powered standalone unit and operates on 100-240VAC.
A Word about the AM Transmitter and Antenna
The performance of an AM station is highly dependent upon the high-power RF sections of the
transmitter, and upon the behavior of the antenna system. The high average power and the
pre-emphasized high-frequency component of processed audio puts great demands upon the
performance of the transmitter and antenna system. While improved results can be expected
from most configuration and settings of a less sophisticated audio process chain, outstanding
results can only be achieved by a properly tuned audio process chain with the minimal
components necessary such as multiband compressor, limiter, gates, and equalizer comparable
to that of a AM broadcast audio processor.
If the antenna system, whether directional or omni-directional exhibits inadequate bandwidth
or a mismatch, often, the system will exhibit both problems simultaneously, the system will
couple RF energy into space with progressively less efficiency at higher sideband frequencies
(corresponding to higher modulation frequencies). It reflects these higher-frequency sideband
components back into the transmitter or dissipates them in the tuning networks. This not only
causes dull sound on the air which defeats the Asymod’s principal advantage which its ability to
pass a highly pre-emphasized audio signal without undesirable side effects but it also wastes
energy, causes distortion, and can shorten the life of transmitter components.