Electronics & Innovation 1240L User manual

The material contained in this document is the property of Electronics & Innovation Ltd., it is subject to
change without notice.
January 2014 Revision E
1
1240L
Broadband Power Amplifier
HIGH RF VOLTAGES MAY BE PRESENT AT THE OUTPUT OF THIS UNIT. All
operating personnel should use extreme caution in handling these voltages and be
thoroughly familiar with this manual.
Do not attempt to operate this unit prior to reading this manual.

The material contained in this document is the property of Electronics & Innovation Ltd., it is subject to
change without notice.
January 2014 Revision E
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Warranty
Electronics & Innovation Ltd., (hereafter E&I) warrants for the period of three years from
the date of original delivery, each unit to be free of defects in materials and workmanship.
For the period of 36 months E&I will, at its option, repair or replace defective parts so as
to render the unit fully operational such that it performs according to the original
specifications; free of charge to the original purchaser.
Should warranty service be required, the unit must be returned to E&I, freight cost to be
borne by the owner. If, in our opinion, the unit has been damaged by use outside the
limits prescribed in this manual or by accident, then the warranty shall not be honored. In
such a case E&I will provide an estimate for repair, assuming repair is possible and
provide a quote at standard service rates.
Contents
Chapter 1
General Information……………………………………………………………3
Chapter 2
Operation………………………………………………………………………..4
Chapter 3
Technical Information………………………………………………………….7
Chapter 4
Maintenance……………………………………………………………………8
Chapter 5
Safety……………………………………………………………………………12

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change without notice.
January 2014 Revision E
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Chapter 1 Introduction
The 1240L is a broadband solid state amplifier covering the frequency spectrum from 30
KHz to 1 MHz. It is rated at 2000 watts of RF power with low harmonic and
intermodulation distortion. Over 2500 watts of saturated power can be produced with
increased distortion products from 100 KHz to 1 MHz. A quasi linear Class AB design, the
1240L will amplify inputs of AM, FM, SSB, pulse and any complex modulation signals.
The amplifier has 58 dB gain, it is unconditionally stable and will not oscillate even with
combinations of mismatched source and load impedance. It is protected against failure
due to output load mismatch and/or overdrive.
RMS forward and reverse powers are monitored by a front panel meter. An integral power
supply permits operation from 200-240VAC VAC 47-63 Hz.
1.2 INSTRUMENTATION IDENTIFICATION
Each amplifier is identified by a serial number tag on the back panel of the unit. Both the
model number and the serial number should be quoted to identify specific unit.
1.3 SPECIFICATIONS
Physical and electrical specifications are listed in Table 1-1 below

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subject to change without notice.
January 2014 Revision E
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Table 1-1. SPECIFICATIONS
FREQUENCY COVERAGE:
20 kHz to 1 MHz
GAIN:
58 dB min, ±1.5 variation
CLASS AB QUASI LINEAR OUTPUT:
2000 Watts min
SATURATED RF POWER OUTPUT:
1500W Min. from 10kHz –20KHz;
2200W Min. from 30KHz –100 KHz
2500W Min. from 100KHz –1MHz;
INPUT IMPEDANCE
50 ohms, VSWR, 1.5:1 Maximum.
OUTPUT IMPEDANCE:
50 ohms, VSWR, 2:1 Maximum
STs STABILITY:
Continuous operation into any load or
source impedance.
PROTECTION:
Unit will withstand a + 16dBm input
signal (1.0 Volts RMS) for all output load
conditions, without damage.
POWER OUTPUT METER:
True RMS power detection. ±5% of full
scale accuracy.
POWER REQUIREMENTS:
200-240VAC VAC 47-63 Hz.
30 Amps Max
SIZE:
24 X 16.75 X 20 inches
330 X 425 x 508 mm.
WEIGHT:
180 pounds 82 kg
CONNECTORS:
N
OPERATING TEMPERATURE:
0 –40 C
RACK MOUNTING:
Chapter 2 Operation
2.1 INTRODUCTION
The 1240L RF amplifier is used to amplify the RF level of signal sources in the 10
KHz to 1 MHz range to. No tuning or any other form of adjustment is required.
The 1240L produces a minimum 2000 watts output at its output connector into 50
Ohms and a minimum of 1,000 watts regardless of load impedance. Power
reflected due to output load mismatch is absorbed in the amplifier. If the reflected
power exceeds 1500 watts the unit will protect itself. Therefore, although the
output impedance is 50 ohms (maximum VSWR: 2.5:1), the amplifier will work
into any load impedance.

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subject to change without notice.
January 2014 Revision E
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2.2 RACK INSTALLATION
This unit is 14U high, 16.75” width. With the handles removed it will fit into a
standard rack.
2.2.1 Mains Voltage
The unit runs of 200-240VAC VAC 47-63 Hz. 30 Amps Max
2.3 OPERATION
A fixed line cord is supplied to form a connection between the mains supply and
the rear of the unit. This is configured from the factory with a 30A plug. Plug this
into the AC mains outlet.
2.3.1 Proceed as follows:
(i) Ensure that there is at least 3” or 7.5 cm clearance at the rear of the
unit for air flow.
(ii) Ensure RF input voltage is not excessive
a. The 1 V rms indicated maximum input voltage is 5 times the level of
the input signal required to achieve maximum output. Input voltages
in excess of 2 volts peak may permanently damage the instrument.
(iii) Connect the output via a 50 ohm coaxial lead and N plug to the load.
(iv) Connect the input signal via a 50 ohm coaxial lead and N plug to the
input connector.
2.3.2 Front Panel Display
The 1240L front panel has a passive LCD display designed for simplicity and
ease of use. During initialization, the LCD shows the software revision. After the
amplifier is initialized, the LCD indicates Forward Power, Reflected Power, and
amplifier status (see figure 2.1).
Pf:___W Pr:___W
Status:________
Figure 2.1 : Front Panel Display
Where Pf refers to forward power, Pr refers to reverse power, and Status
indicates “OK” unless there is a fault condition, such as:
Overheat (heat-sink temperature is too high for reliable operation)
PSU fault (internal fault in the main switching power supply)

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subject to change without notice.
January 2014 Revision E
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In the event of a fault, the unit may be reset by cycling the power. In the case
over an over temp fault, ensure that the air inlet and out let are not restricted. If
the fault persists, please contact Field Service.
2.3.3 RS 232 Interface
The 1240L features a standard RS-232 serial interface suitable for connection to
a PC or host system. The communication protocol is extremely simple to
facilitate readback and control with readily available terminal programs such as
Hyperterm. The RS-232 link has the following parameters:
Baud rate: 19200
Data bits: 8
Parity: none
Stop bits: 1
Flow control: none
An example configuration using HyperTerminal on a PC is shown in figure 2.2.
In the default state, the RS-232 port will echo the same information sent to the
front panel LCD display, allowing a running datalog to be stored to disk using the
capture feature of the terminal program.
Single character commands can be sent to the amplifier to achieve the following:
Figure 2.2: Example RS-232 setup using Hyper Terminal

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subject to change without notice.
January 2014 Revision E
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"1" key enables telemetry (readback similar to LCD display) - this is the default
mode at power up
“2” key clears any faults and tries to start the supply.
“0” key disables telemetry (Complement to “1” key)
Custom commands and display lists can be implemented upon customer
request.
Chapter 3 Technical Description
3.1 GENERAL DESCRIPTION
The 1240L is designed to amplify signals by 58 dB in the frequency band of 20
KHz to 2 MHz. The signal from the front panel N connector is fed via a length of
50 ohm coaxial cable into the input of the pre-amp splitter module. The signal
from the output of the splitter is coupled to the input drivers 1) - 4) the first stage
of each is the MMIC front end. The output signal of the MMIC is coupled to the
gate of transistor Q1. The further amplified signal appearing at the drain of Q1 is
coupled to the input of Q2. This is transformed to 50 and fed to the driver
output BNC port.
The driver output signal are fed through a length of coaxial cable to the input of a
power splitter, the outputs of this are fed to the power amplifier modules. In each
PA module the signal is split into two equal phase and amplitude signals. These
signals are fed to the inputs of transistors Q1 and Q2. The amplified signals
appearing at the drains of Q1 and Q2 are then fed to the output BNC port via the
impedance matching network. The output of the modules is then fed to a
combiner to produce a single signal.
The power signal is then fed into a length of 50 ohm coaxial cable to the RF bi-
directional coupler. The output of the coupler is then fed directly to the N
connector on the front panel, this is the unit output.
The forward and reverse coupled ports of the bi-directional coupler are fed to the
RF detector which is situated on the main control board. The RF detector feeds a
voltage, which is representative of the true RMS power to the control board
proper. The control board in turn drives the front panel display.
There are four switch mode power supply units three provide a 42 VDC 35
ampere source. The other provides 24 VDC outputs and provides 10 amps. The
main power supply also has a 5 VDC output which feeds the control board.

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subject to change without notice.
January 2014 Revision E
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Coupler
RF IN
RF OUT
To Page 2 c
RF Detect
1240L RF Amplifier
Splitter
Driver 1
24 Volt
To Page 2 a
To Page 2 b
To Page 2 b
42 Volt
42 Volt
2100L PA
2100L PA
2100L PA
Driver 1
Splitter
2100L PA
42 Volt
Splitter
Driver 1
24 Volt
To Page 2 a
To Page 2 b
To Page 2 b
42 Volt
2100L PA
2100L PA
2100L PA
Driver 1
Splitter
2100L PA
Combiner
Combiner
Combiner
1240L –SCH-01

The material contained in this document is the property of Electronics & Innovation Ltd., it is
subject to change without notice.
January 2014 Revision E
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Chapter 4 Maintenance
4.1 INTRODUCTION
The E&I 1240L RF amplifier requires no periodic maintenance. The instrument is
unconditionally stable and is fail-safe under all load conditions. Damage can only
be externally caused by the incorrect selection of the AC supply voltage or by an
input signal in excess of the specified 1 volt rms equivalent to a power level of
16dBm.
This chapter therefore, deals only with certain fundamental procedures for fault
location.
AC IN
SMPS 42 Volt
SMPS 42 Volt
SMPS 42 Volt
SMPS 48/24 Volt
To page 1 a
24 Volt
To page 1 b
Controller
To page 1 c
TTL Control
Front Panel LCD
To Rear
Panel RS232
Fans
CKT
BRK
Line
Filter

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subject to change without notice.
January 2014 Revision E
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Performance limits quoted are for guidance only and should not be taken for
guaranteed performance specifications unless they are also quoted in the
Specification Section 1.2.
4.2 PERFORMANCE CHECKS
To determine the amplifier’s performance carry out the following procedure.
4.2.1 Initial Check
The following check can be made after repair and adjustments or
whenever the condition of the unit is in question.
a. Connect AC power supply. Switch on power and observe that the
display initializes.
b. Connect a sweep generator (HP 8601 or similar) capable of sweeping
the frequency range 30 KHz to 1 MHz, to the input connector.
c. Adjust the output level of the sweep generator so that a 50 ohm video
detector connected at the output of the unit will not be damaged by
excessive power output. (Reference section 4.4.1 for set up.)
d. Observe the gain versus frequency ripple on an oscilloscope calibrated
in decibels. The gain variation must be not more than +/- 1.5 dB over
the frequency range.
e. Connect a calorimetric power meter (HP435B or equivalent) through a
30 dB 5000 watt attenuator to the output connector. Adjust the input
CW signal to any frequency between 30 kHz and 1 MHz for 2000 watts
output.
f. Observe the harmonic distortion of the output, properly attenuated, on
a spectrum analyzer. The harmonic components contributed by the
amplifier should be better than 10 dB down from the fundamental.

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subject to change without notice.
January 2014 Revision E
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4.3.1 Measurement of Gain
1. Equipment Required (or equivalent):
a) Osilloscope - Tektronix T921
b) Sweep/Generator - HP8601A
c) Signal Generator - Exact Model 7060
d) 50 ohm Detector - Wavetek D151
e) Attenuator, 30 dB, 5000 Watts Bird
Figure 4-1. Gain Measurement
2. Connect the equipment as shown in Figure 4-1, then proceed as follows:
a) Set the oscilloscope to DC, Time/cm to Ext. X, and gain to
l0mv/cm.
b) Set the sweep generator to the video sweep mode with the start
frequency at 30 kHz and the sweep width to 1 MHz.
c) Disconnect the 1240L from the set-up and connect the
sweep/generator RF output directly to the 50 dB attenuator.
50 dB Attenuator
RF Detector
Sweep Generator
RF Output
Sweep
Signal
Trigger
30 KHz –1 MHz
Input

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subject to change without notice.
January 2014 Revision E
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d) Adjust the output level of the sweep/generator for full vertical
deflection on the oscilloscope face.
e) Calibrate the scope face to show 3 dB in 1 dB steps by
attenuating the sweep/generator in 1 dB.
f) Return sweep/generator output level to full deflection. Rotate the
step attenuator (CCW) so that the output is reduced by 50 dB.
g) Reconnect the 1240L into the test set-up of Figure 4-1.
h) Place the 1240L power switch to the "ON" position.
i) Observe the gain versus frequency sweep on the oscilloscope.
The average gain should be greater 55 dB
The gain variation should be within the 3 dB as shown on the
oscilloscope.
4.4.2 Measurement of Harmonics
Figure 4-2.
1.) Equipment Required:
a) Sweep/Signal Generator
b) Calorimetric Power Meter HP435B
c) Spectrum Analyzer.
50 dB Attenuator
Sweep Generator
RF Output
30 KHz –1 MHz
Spectrum
Analyzer
Power Meter
30 dB
coupler

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January 2014 Revision E
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d) Attenuator (30dB)
e) Coupler (30 dB)
2.) Connect the Equipment as shown in Figure 4-2, then proceed as follows:
a) Adjust the signal generator to a CW center frequency of 30 kHz, for an
indicated output of 2000 watts on the power meter.
b) Using the spectrum analyzer, check that the level of the carrier
harmonics is less than -10 dB with respect to the carrier while manually
scanning the frequency band of 30 KHz to 1 MHz. An indicated power
output of 2000W should be maintained during this operation.
4.5 PACKAGING FOR RESHIPMENT
In the event of the equipment being returned for servicing it should be packed in
the original shipping carton and packing material. If this is not available, wrap the
instrument in heavy paper or plastic and place in a rigid outer box of wood,
fiberboard or very strong corrugated cardboard. Use ample soft packing to
prevent movement. Provide additional support for projecting parts to relieve
these of unnecessary shock. Close the carton securely and seal with durable
tape. Mark the shipping container FRAGILE to ensure careful handling.
Chapter 5 Safety:
Do not attempt to operate this unit with the cover removed. High AC and DC
voltages are present. The cover protects against electrical shock due to AC line
voltages, high DC and RF fields. Further the cover provides part of the cooling
system design. Components, specifically on the RF driver board are prone to
over-heat and eventual failure if the unit is operated without the cover in place.
Ensure that the load is connected to the output prior to connecting the RF input
to the unit. This will prevent high voltages being present and exposed at the
output connector.
Only use the AC cord provided or equivalent.
Ensure that the mains outlet is properly grounded.