eb104 EB500 User manual

eb104.ru™
User's manual
Transistor linear
VHF power amplifier 500 W
Model EB500

Contents
Introduction ………………………………………………..3
Precautions for use with the E 500 ……………………3
Functional features of the E 500 amplifier ……………4
Characteristics of the E 500 amplifier .........................4
Front Panel Description ………………………………….6
Description of the rear panel …………………………....6
Connecting the control cable ……………………………7
E 500 Power Amplifier Protection Circuits ...................7
Application …………………………………………………9
Warranty ......................................................................11

Introduction
efore using the E 500 Power Amplifier, carefully read this manual and other
documentation that came with your amplifier. This will allow you to reduce the risk of failure
of this product.
E 500 is a transistor linear VHF power amplifier designed for use with amateur radio
stations. Distinctive features of the E 500 amplifier:
–instant availability for operation;
–compact size, light weight;
–no need to replace components due to wear;
–increased service life;
–lack of high voltage in the high-frequency part;
–the ability to automate operation.
Operating Precautions EB500
For the power amplifier to work properly, you must follow some precautions:
–The operation of the amplifier without an appropriate electrical grounding
s stem is required;
–If possible, organize the chassis grounding of the radio-transmitting device, which
will ensure the most efficient and stable operation of all the equipment of the
amateur station, and will reduce the level of possible interference and RF
interference; ground all station equipment to a common ground.
–If the protection systems of the amplifier are repeatedly activated, it is necessary to
stop the operation of the amplifier until the causes of the emergency shutdown are
eliminated. Multiple tripping of protection systems can damage expensive LDMOS
transistors;
–Do not drop, or damage the case, or allow foreign objects inside - this may lead to
the failure of the electronic components of the E500 power amplifier.
–Do not operate the power amplifier with the covers removed to avoid overheating of
the device. The absence of covers disrupts the cooling system.

Functional Features of the EB500 Amplifier
The built-in potentiometers in the protection circuit and the IAS voltage control circuit are
set to the correct position during setup and testing of the equipment. Any change in the
position of these potentiometers will result in the need to reconfigure the amplifier using
accurate measuring instruments.
efore operating the power amplifier, it is necessary to connect a load equivalent of 50
ohms, minimum 500 watts or a matched antenna with known low SWR to the output
antenna connector. The operation of the amplifier without load negatively affects the
operation of the output RF transistors.
To obtain an output power of 500 watts, the input power level should be no more than 50
watts. It is not recommended to use transmitters with an output of more than 50 watts with
an amplifier.
The amplifier is designed for an impedance of 50 ohms. If the antenna-feeder devices are
matched to a resistance of 50 Ohms, and the SWR on all operating ranges does not
exceed the value of 1.5 to 1, then the amplifier can be operated without additional
coordination. If the SWR is greater than 1.5 to 1, then the use of additional matching
devices is recommended.
In the output stage of the power amplifier, two high-quality LDMOS transistors MRF300AN
and MRF300 N are used.
The rated power of each MRF300 transistor is 300 watts. The use of high-linear transistors
also allowed to obtain IMD3 -30 dbC.
The process of switching the transmission in the amplifier allows the TIAN O relay a
switching time of 30ms. Insure your transmitter delay is set to allow amplifier adequate
time to change over to avoid hot switching.
The power amplifier is equipped with special high-speed protection circuits. For example,
from excess of output power, high value of SWR in the antenna, high drain current of
output transistors and overheating.
To control the operating parameters of the power amplifier, a digital measuring device is
used, on which the output power level and the SWR value are displayed.
Frequency range
Types of radiation
Input power
output power
Maximum SWR in the antenna
Supply voltage
Consumption current
Input impedance
Output impedance
Input / output connectors
Amplifier circuit
Output Stage Transistors
Dimensions - W x H x D (mm)
Weight (gr.)
144-148 MHz
SS , CW, DIGI, RTTY
50 watts
500 W (SS / CW, DIGI, RTTY)
1.5: 1
30 ... 53V
15A max (53V each)
50 ohm (unbalanced)
50 ohm (unbalanced)
UHF SO-239
push-pull class A
MRF300AN, MRF300 N
290x140x205
3900

Front Panel Description
1. Key switch on and off the power amplifier.
2. Digital power indicator and SWR.
3. Green LED - indicates transmission mode.
4. Over current protection indicator
5. Protection indicator for excess SWR
6. Protection indicator for exceeding the maximum permissible output power
Turn the amplifier off and on again to reset the protection circuit.

Back panel description
OUT - RF connector for connecting the antenna.
CONTROL - connector for PTT signal.
IN - connector for connecting a coaxial cable from the transceiver.
53V - connector for connecting a 30-53V power supply.
Control cable connection:
15 pin - PTT, connection to the housing enables transmission mode
22-25 pin - GND, common wire.

EB500 Power Amplifier Protection Circuits
1. Overheat protection.
If the temperature of the transistor case exceeds + 70 ° C, the bimetallic thermal switch
located on the transistor case will be triggered and transmission becomes impossible, until
it cools down to + 65 ° C.
2. Protection against exceeding the maximum permissible output power.
If the output power level exceeds the permissible threshold, a protection will be activated
that disconnects the power from the output transistors. The P LED lights up on the front
panel. A power cycle is required to reset the protection.
3. Protection against high SWR.
If the SWR in the load exceeds the value of 1.5: 1, then the protection system will trigger.
The SWR LED on the front panel lights up. To reset the protection, turn off the power. In
case of protection operation, we recommend checking the SWR antenna and feed line.
Insure feed line and connectors are adequate for handling 500 watts
4. Protection against exceeding the maximum permissible current.
If the current value of the output transistors exceeds the permissible threshold, a
protection will be activated that disconnects the power from the output transistors. The
LED I on the front panel lights up. To reset the protection, turn off the power.

Application