E&I 3100LA User manual

3100LA
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.

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subject to change without notice.
May 2016 2 Revision G
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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Chapter 1 Introduction
The 3100LA is a broadband solid state amplifier covering the frequency spectrum
from 250 KHz to 150 MHz. It is rated at 100 watts of RF power with low harmonic
and intermodulation distortion. 150 watts of saturated power can be produced
with increased distortion products. A highly linear Class A design, the 3100LA will
amplify inputs of AM, FM, SSB, pulse and any complex modulation signals. The
amplifier has 50 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 115/230 single phase AC power.
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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Table 1-1. SPECIFICATIONS
FREQUENCY COVERAGE:
250 kHz to 150 MHz.
GAIN:
50 dB min, ±1.5 variation.
CLASS A LINEAR OUTPUT:
Nominal 100 watts.
HARMONIC DISTORTION:
> -25 dBc at 100 watts output.
SATURATED RF POWER OUTPUT:
150W Min.
INPUT IMPEDANCE
50 ohms, VSWR, 1.5:1 Maximum.
OUTPUT IMPEDANCE:
50 ohms, VSWR, 2.5:1 Maximum
STs STABILITY:
Continuous operation into any load or source
impedance.
PROTECTION:
Unit will withstand a + 13dBm input signal (1.0
Volts RMS).
POWER OUTPUT METER:
True RMS power detection. ±3% of full scale
accuracy.
POWER REQUIREMENTS:
100 –240 VAC 47-63 Hz.
SIZE:
5.3” 5.3”x 16.5” x 18.4”
134.134.5 mm x 420 mm x 467 mm
WEIGHT:
52 pounds 23.6 kg
CONNECTORS:
N
OPERATING TEMPERATURE:
0 –40 C
RACK MOUNTING:
Optional Rack Mount Ears
Chapter 2 Operation
2.1 INTRODUCTION
The 3100LA RF amplifier is used to amplify the RF level of signal sources in the
250 KHz to 150 MHz range. No tuning or any other form of adjustment is
required.
The 3100LA produces rated power output at its output connector, regardless of
load impedance. Any power reflected due to output load mismatch is absorbed in
the amplifier. Therefore, although the output impedance is 50 ohms (maximum
VSWR: 2.5:1), the amplifier will work into any load impedance.
2.2 RACK INSTALLATION
This unit is 5U high, 17” width. With the handles removed it will fit into a standard
rack.

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2.2.1 Mains Voltage
The unit accommodates AC line voltages from 100 TO 240 VAC 47 –63 Hz
2.3 OPERATION
A line cord is supplied to form a connection between the mains supply and the
rear of the unit. Plug this into the AC input at the rear of the unit and 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 3100LA 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)
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 Service Department.

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2.3.3 RS 232 Interface
The 3100LA 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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"1" key enables telemetry (readback similar to LCD display) - this is the default
mode at power up
Custom commands and display lists can be implemented upon customer
request.
Chapter 3 Technical Description
3.1 GENERAL DESCRIPTION
The 3100LA is designed to amplify signals by 50 dB in the frequency band of 250
KHz to 150 MHz. The signal from the front panel N connector is fed via a length
of 50 ohm coaxial cable into the input of the driver amplifier module. The signal
from the input of the driver is coupled to the input of 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 N port.
The driver output signal is fed through a length of coaxial cable to the input of the
splitter network. The two output signals are fed to the two power amplifiers. Each
amplifier has a four way splitter the outputs of which are fed to the individual PA
PCBs each containing an RF MosFet that is in a push-pull configuration. The
output of these are then fed to the combining network of the PA module.
The power amplifier module output is fed 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.
The main power supply unit provides a 24 VDC 12 ampere source. It is a switch
mode power supply unit. The output feeds the PA and the drive amplifier. The
main power supply also has a 5 VDC output which feeds the control board.

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subject to change without notice.
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Chapter 4 Maintenance
4.1 INTRODUCTION
The E&I 3100LA 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 13dBm.
This chapter therefore, deals only with certain fundamental procedures for fault
location.
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.

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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 250 KHz to 150 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 (HP434 or equivalent) through a
10 dB 200 watt attenuator to the output connector. Adjust the input CW
signal to any frequency between 250 kHz and 150 MHz for 100 watts
output.
f. Observe the harmonic distortion of the output on a spectrum analyzer.
The harmonic components contributed by the amplifier should be
better than 25 dB down from the fundamental.
(a) If the above items are found to be outside of the specification, check
the spectral content of the input signal. If this is a pure signal then
the unit needs to be returned to the factory for service.
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

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d) 50 ohm Detector - Wavetek D151
e) Attenuator, 30 dB, 200 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 150 kHz and the sweep width to 150 MHz.
c) Disconnect the 3100LA from the set-up and connect the
sweep/generator RF output directly to the 30 dB attenuator.
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 steps.
f) Return sweep/generator output level to full deflection. Rotate the
30 dB Attenuator
RF
Detector
Sweep Generator
RF Output
Sweep
Signal
Trigger
250 KHz–150 MHz
Input

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step attenuator (CCW) so that the output is reduced by 50 dB.
g) Reconnect the 3100LA into the test set-up of Figure 4-1.
h) Place the 3100LA power switch to the "ON" position.
i) Observe the gain versus frequency sweep on the oscilloscope.
The average gain should be greater 50 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.
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 250 kHz, for an
indicated output of 100 watts on the power meter.
b) Using the spectrum analyzer, check that the level of the carrier
harmonics is less than -25 dB with respect to the carrier while manually
scanning the frequency band of 250 KHz to 150 MHz. An indicated
power output of 100W should be maintained during this operation.
30 dB Attenuator
Sweep Generator
RF Output
150 KHz –150 MHz
Spectrum
Analyzer
Power Meter
30 dB
coupler

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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 prevents 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.