Specifications

5
DOCNUMBER 9500
Document Issue 1, Revision 7
June 2009 Page 5–9
Alpha Radio Products Alpha 9500 HF Linear Amplifier Operating Manual
Product Release 1 Setting Up the Amplifier
Step 4 Place the amplifier in its operating position on a stable surface with
sufficient space to the rear, sides, and top to allow good air flow and safe
placement of cables.
Step 5 Connect the amplifier RF INPUT to the transceiver RF OUTPUT.
Use 50-ohm coaxial cable-RG-58C/U or equivalent. A 6-ft. cable is
supplied for this purpose.
Step 6 Connect the amplifier RF OUTPUT to the antenna.
Use RG-8A/U, RG-213/U, or equivalent high-quality cable with a PL-259
UHF-type plug on the amplifier end. Do not use RG8X cable, because it
is not rated for 1500 W.
Step 7 Connect the transceiver (T/R) control cable to the amplifier.
HINT: The T/R control cable is also known as the keying cable.
The amplifier has a full break-in vacuum relay QSK system that requires
only the normal interconnection when used with a modern QSK
transceiver. The amplifier requires a contact closure (short circuit) on
transmit from its RELAY jack center pin to the chassis. This function is
supplied by the transceiver, usually from a dedicated relay that is
normally open in receive and closed in transmit.
7a Use shielded wire for the T/R control cable. Fit the amplifier end with
a common phono (RCA-type) plug and the transceiver end with a
suitable connector.
7b Ensure that the T/R relay contact closes. Protection circuitry prevents
hot-switching when RF drive is applied. Modern transceivers have
the proper time delay between key-up and the start of the transmitted
signal to allow the amplifier to follow the CW keying.
If you suspect a T/R timing problem:
1. Connect the CW keyer to the RELAY jack on the amplifier.
2. Connect a cable from KEY OUT on the amplifier to the keying
input of the transmitter.
3. Ground the key cable (they should key up).
4. Apply power from the transmitter. The amplifier should respond
with power out to the antenna.
NOTE: The amplifier does not generate or use Automatic Level
Control (ALC) voltages to control an exciter.