User's Manual

ALPHA 9500 Interim OPERATING MANUAL
www.alpharadioproducts.com
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Yeasu RF –
T/R – Connection with the RCA “TX GND” connector. Also with the
DIN “Band Data” connector. See the transceiver User’s Manual for
information.
Kenwood RF –
T/R – See the transceiver User’s Manual for information on
connecting to external amplifiers.
Older Transceivers See the transceiver User’s Manual for information on connecting
to external amplifiers.
6.3 Initial Setup & Tuning
The Alpha 9500 (like its predecessor the Alpha 87A) requires careful initial setup in order for the
unit to function in an optimum fashion. When the amplifier is first keyed and RF is sensed, the
frequency of the signal is measured and the ampflier then moves to the appropriate band and
segment and sets the tune and load capacitor positions to the values that were saved for that
frequency. If a different antenna was saved for that band, then the new antenna position will be
selected. At the factory the amplifier is tested and tuned into an Alpha 2100, 50 ohm dummy
load and the correct tune and load capacitor values are stored into the default memory segment
positions. The user is expected to retune the amplifier for their particular station setup and to
save those settings to the user memories. Once the ampflier has switched to the correct tune
and load settings for that particular frequency, the user may choose to “touch up” , the capacitor
settings to achieve maximum output. The output tuning on the amplifier is set to be broadband
and changing frequencies by up to 100 kHz, should not normally require retuning.
The one-pass auto-tune functionality of the amplifier is engaged whenever the Auto button is
pressed on the front panel and the output power is above 150 watts. The auto-tune algorithm
varies the capacitor tune and load settings while paying attention to grid and plate current to
achieve maximum efficiency. The amplifier is designed to operate most efficiently at 1500 watts
of output power, although it can easily be used at lower power levels.
When you first install the Alpha 9500 in your shack, you should save the tune and load settings
for your setup and antennas to the User 1 memory. Note that for each band, there are 5 segment
values, representing 5 different frequencies across that band. The tune and load settings that are
saved in each location provide a good starting place for the auto-tune algorithm to begin. You
may choose any “favorite” frequencies to use as the saved value for each segment as long as they
increase monotonically from segment 1 through segment 5. The frequencies for each segment
and band in the factory default memories are listed in Appendix.