AMERITRON AL-80 - Installation

VENTILATION
The back of the AL-80 must not be closer
than 4 n from a wall or other obstruction
to the air outlet of the blower. This is
essential for proper cooling of the 3-5G0ZJ
IMPORTANT: The AL-80 must be on a
clear flat surface to allow proper air in¬
take*
The AL~80 has been carefully tested to
maintain the tube seal temperatures safely
below the manufacturers ratings during a
7 5% duty cycle ( 10 minutes on, 5 minutes
off operation ) at 500 watts dissipation.
For longer duty cycle in high dissipation
operation (SSTV, AM, etc.) a higher fan
speed is recommended. Call or write the
technical department for our cooling re¬
commendations. Complete details of your
anticipated operation are necessary*
POWER CONNECTIONS
The AL-80 is shipped with the transformer
primary connected for 117 V.A.C. operation.
If 234 V.A.C. operation is desired the
primary connections must be changed on
the terminal board located on the rear of
the AL-80. Refer to the diagram shown
below. Remove the 15 ampere fuse and
replace it with a 7.5 ampere fuse.
117 VOLT OPERATION 234 VOLT OPERATION
CONNECT 1 TO 3 CONNECT 2 TO 3
2 TO 4
When the AL-80 is operated on 117 volts
A.C. be sure the wiring between the fuse
box and the A.C* outlet is of adequate
gauge to provide the current required
without a significant drop in line voltage.
No. 12 wire is recommended.
INSTALLATION
Connect the RF output of the transceiver
to the RF input connector on the rear of
the AL-80 with 50 ohm coax. Connect the
existing station antenna system to the RF
output connector on the AL-80 using RG8
type cable. The station antenna system
must be equipped with a watt meter or
SWR bridge for proper tuning of the
AL-80. A phone jack on the rear of the
AL-80 is provided for connection to a
pair of normally open relay contacts in
the transceiver which close on transmit.
Another phone jack for ALC is located on
the rear of the ALt80.
Connect as short a ground lead as possible
from a good earth ground to the AL-80
rear panel GND terminal.
ALC
A shielded audio type cable should be used
to connect the 0-30 volt negative ALC volt¬
age to the transceiver ALC input. Consult
your transceiver manual for proper attach¬
ment details*
Proper adjustment is obtained by watching
a monitor scope for flat-topping and ad¬
justing the ALC until peak clipping does
not occur with the AL-80 fully loaded into
a 50 ohm load with the audio control of the
transceiver on full.
A general indication that a peak clipping is
being approached occurs when the grid(Ig)
current reaches 50% of the single tone drive
level (normally 125-150 ma) on a speech
waveform.
QSK
The QSK functions with a controlled loss
feedback system. Receive attenuation will
be - 20 db on 10 meters and increase a
few DB per octave as the frequency is re¬
duced. A few seconds after transmitting
the attenuation is removed. No special
hook-up is required for use with a QSK
transceiver.