OM POWER OM1002 User manual

Instruction Manual
OM1002
Solid State 145 MHz Power Amplifier
OM POWER, s. r. o. 930 30 Báč126
SLOVAKIA
E-mail: [e-mail]

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TABLE OF CONTENTS
1. GENERAL INFORMATION
1.1. Introduction ……………………………………………………………….. 4
1.2. Specification …………………………………………………………….... 4
1.2.1. Parameters …………………………………………………………………. 4
1.2.2. Protection Circuits ………………………………………………………… 4
1.2.3. Indicators ………………………………………………………………….. 5
2. SAFETY INSTRUCTIONS ……………………………………………… 5
3. GENERAL DESCRIPTION ………………………………………………. 6
3.1. HF part ……………………………………………………………………. 6
3.2. Power Supply …………………………………………………………….. 8
3.3. Safety Devices ……………………………………………………………. 8
4. INSTALLATION ………………………………………………………… 9
4.1. Grounding ………………………………………………………………… 9
4.2. Coaxial Cable …………………………………………………………....... 9
4.3. Control Cable ………………………………………………….…………... 9
4.4. Main Supply ………………………………………………………………. 11
4.5. Cooling ……………………………………………………………………. 11
5. OPERATION ……………………………………………………………… 11
5.1. Operation Elements ……………………………………………………….. 12
5.2. Preparation for operation …...……………………………………………… 13
5.2.1. Display Menu ……………………………………………………………… 14
5.2.2. Settings Menu ……………………………………………………………… 15
5.2.2.1. Own text editing ………………………………………………………….. 16
5.2.2.2. Display delay ……………………………………………………………... 16
5.2.2.3. Bias delay ………………………………………………………………… 17
5.2.2.4. Preamplifier delay ………………………………………………………… 17

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5.2.2.5. Bias SSB No.1 ………………………………………………………….. 18
5.2.2.6. Bias CW No.1 ………………………………………………………….. 18
5.2.2.7. Software version ……………………………………………………….. 19
5.2.3. Operating mode ………………………………………………………… 19
6. MAINTENANCE ………………………………………………………. 23
6.1. Indication of Fault Conditions …………………………………………. 23
6.2. Fuse Replacement . .………………………………………………….... 24
6.3. Cleaning ……………………………………………………………....... 25
7. APPENDIX ……………………………………………………………... 26
7.1. Block Diagram ………………………………..………................................ 26

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1. GENERAL INFORMATION
1.1. Introduction
The OM Power model OM1002 is a single band, solid state amplifier, designed for duty
operation on 2 meter’s amateur band with all modes and no time limit. It is equipped with
a new Freescale high rugged N-channel double MOSFET. This amplifier is characterized by
compact design, small size and a low weight.
1.2. Specification
1.2.1. Parameters
Frequency Coverage 144 – 148 MHz Amateur Band
Power Output 1000W in CW, 800W SSB (linearity), RTTY,
AM, FM and digi, 50% duty cycle.
Input Power 10 to 15 W for full output power 1000W
Input Impedance 50 Ohm, VSWR < 1.3 : 1
Power Gain Typically 19 dB
Output impedance 50 Ohm unbalanced
Maximum output SWR 1,9 : 1 for full output power 1000W
SWR protection: Automatic switching to STBY , when reflected power is
100W or higher
Intermodulation distortion - 32 dBc
Suppression of harmonics < -60 dBc
MOSFET MRFE6VP61K25HR6
Cooler 3 axial fans + 2 axial fans (power supply)
Supplying 100 – 250VAC , 50 – 60 Hz
Power Supplies inside 50V DC switch mode PS
12V DC for logic and protection circuits
Size 270 mm x 200 mm x 345 mm [10.6” x 7.9” x 13.6”]
(Width x height x depth)
Weight 12 kg ( 26.5 lb )
1.2.2. Protection Circuits
There is several special protection circuits used in the amplifier. They are activated when one
or more of next parameters exceed defined values or some unwanted occasion occurs.
·Output power too high
·Reflected power too high
·Drain current too high
·Gain to low
·DC voltage too low or DC voltage error
·Input power too high (hardware protection & software protection)
·Inside temperature too high
·Soft start for power supply protection (PS feature)

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1.2.3. Indicators
There are few visible LED indicators on the front panel for information on operating
condition, a few buttons and a graphic display.
LED Indicators STBY - Standby mode
OPERATE - Operation mode
CW - CW mode
PREAMP - Control voltage +12V DC for optional RX
preamplifier switching
FAULT - Failure
ON AIR - Transmit mode
Buttons UP – DWN - Listing in LCD menu
- Scroll trough the alphabet in edit mode
- Changing parameters
OPER - Operation mode
SET - confirms parameters
- Cursor to the right in edit mode
- Settings menu
PRE - Preamplifier ON
- Edit mode start, cursor to the left in edit mode
CW/SSB - mode switch
OSD Indicator 140 x 16 dot graphic display to view:
- Display menu
- Settings menu
- Warning & fault messages
2. SAFETY INSTRUCTIONS
WARNING! Before you will start to install and operate power amplifier, read carefully
next safety instructions!
WARNING! AVOID CHILDREN to play around PA or to touch power amplifier or
connected cables in working condition, or to push anything into the fan holes!
WARNING! Never turn the amplifier on without the upper lid in place.
WARNING! The OM1002 amplifier is neither to be used in a WET or HUMID
environment nor to be exposed to RAINFALL!

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WARNING! Do not turn the amplifier on without having connected the ANTENNA or
properly rated DUMMY LOAD! A hazardous HF voltage may build up on the antenna
connector after turning the amplifier on with no antenna or dummy load connected!
WARNING! Before opening the upper lid of the amplifier make sure that power supply
has been disconnected. Take out power cord from the outlet!
CAUTION! The amplifier must be installed in such a way that free flow of hot air from
inside is allowed. The amplifier must not be installed in a constrained surrounding (i.e.
tight shelves etc.)
CAUTION! The amplifier must be properly grounded during operation.
CAUTION! During operation the amplifier must be installed in such a way that the
rear panel will stay accessible.
CAUTION! The amplifier is an A category product. In a household it can influence
other electric appliances. In such cases the user is to take proper actions to mitigate this
disturbance.
CAUTION! Read this manual carefully. Follow all of instructions during installation
and operation to avoid damage to the amplifier not covered by manufacturer’s
warranty! Do not attempt to perform any change of hardware or software!
3. GENERAL DESCRIPTION
3.1. HF part
OM1002 power amplifier was designed to achieve the RF performance of the MOSFET,
when applied to the 144 – 148 MHz frequency band. Design was tuned for performance at
1000W CW output, 50VDC. It consists of „no tune“ distributed element matching circuits
designed to be as small as possible.
For operating it is important that adequate heat sinking was provided for the design.

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Look at the RF board
The coaxial transformer turns ratio was chosen to meet required impedance level and the
length of the coax was tuned to achieve maximum efficiency and maximum power transfer
between the device and its load impedance.
Top view on the opened OM1002
Input / Output Relay HF Board Output LPF
Supply Board for Control circuits Switch Mode Power Supply

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3.2. Power Supply
The amplifier uses two power supplies. A professional switch mode power supply 50V / 32A
for power amplifier, and small 12V power supply for logic and protection circuits.
Main power supply contains special soft start circuits, uses two fans, which are visible from
the rear side of PA. It has its own logic to control these fans speed.
Power amplifier should be connected to any external source of AC in the range from 100VAC
to 250VAC, 50 or 60 Hz. It can be powered by a portable generator, for example.
Switch Mode Power Supply and the
Supply Board. Two fuses are visible.
3.3. Safety Devices
Control and monitoring circuits ensure control and safety during malfunctions of the PA.
These are on the Control board and the Protection board. Control board is located behind the
front panel. Protection board is visible on the right hand side of PA, close to the input/output
relay.
Protection Board at the top
Input/Output Relay in the middle
Communication Board at the bottom
(LAN)

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4. INSTALLATION
NOTE
Read this chapter carefully prior starting with installation. Before unpacking inspect shipping
carton first, if it is not damaged. Keep all of packing parts for possible future shipment. Check
unpacked power amplifier. If you find some damaging, contact your dealer immediately to
keep full warranty.
During installation go step by step according to next parts.
4.1. Grounding
CAUTION
The amplifier has to be grounded properly! Connect the screw on the rear panel of the
amplifier to your local grounding system with a copper cable; use a cross-section of 4
mm2at least.
Connect your transceiver to the same grounding system of your shack carefully!
Use minimum length of cables and make sure that the connections are both physically and
electrically sound. With poor grounding, you may risk damaging to your equipment, having
problems with TVI/BCI or your transmitted signal may be distorted.
4.2. Coaxial Cable
The output of the transceiver is to be connected to the input of the amplifier via RG58 or
similar cable. For the connection between the power amplifier and the antenna, Belden 9913
or similar coaxial cable suited for high power is recommended. Both the INPUT and
OUTPUT N sockets with Teflon insulation are used.
4.3. Control Cable
Control cable maintains TX / RX switching of the PA (TX GND). The cable is shielded. On
the side of the power amplifier a CINCH-socket is used. On the side of your transceiver you
have to use a socket suitable for this transceiver. During transmitting the middle pin is
connected to the ground.
Amplifier uses one double coaxial relay for input and output (input and output are switched at
the same time). It has to be switched earlier than HF is applied (cold switching).
Modern transceivers have a time delay between PTT switching and power output.

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Rear view of the amplifier OM1002
RF Output RF Input AC Power Socket
PS Fans
LAN - Local Area Network connection for REMOTE CONTROL of PA (for future use)
PREAMP -RCA Phono, +12V / 100mA for an external RX preamplifier switching
CAUTION
If you are using an older transceiver or transmitters without time delay, we recommend
to connect the PA in such a way that the transmit/receive switch (foot switch for
example) is connected with the KEY IN socket of the amplifier. The KEY OUT socket is
to be connected with the PTT socket at the transceiver.
The amplifier is equipped with two safety devices, which ensure that the output relay is not
switched under power mistakenly (hot switching).
KEY IN - RCA Phono – Input signal PTT (switching voltage / current 5V /2 mA)
KEY OUT - RCA Phono – Output signal PTT (maximum switching of 50V / 100mA)

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4.4. Main Supply
CAUTION
Be sure you got PA with properly terminated line cable, corresponding with your power
system’s outlet. If not, contact your dealer. In such a case you should make the necessary
changes using a licensed electrician.
WARNING!
Be sure that your power system is correctly wired and properly rated! To use
adequately sized and connected grounding system is also very important.
4.5. Cooling
CAUTION
The amplifier must be installed in such a way that free flow of hot air from the amplifier
is allowed. Do not obstruct air intake and exhaust areas of the PA.
All of installed axial fans provide adequate cooling of the amplifier, even during long time
operation. Three upper fans they are activated, when inside temperature exceeds 40 deg.
Celsius. Their speed is gradually rising with increasing temperature. Two fans inside the
power supply start to operate depending on the current drawn by the MOSFET.
When the amplifier reaches inside temperature of 70 deg. Celsius, warning message
„Amplifier is too hot” appears on the display. At 75 degrees protection circuit will
automatically blocked transmitting.
5. OPERATION
WARNING!
Before switching PA on, make sure that amplifier is grounded, antenna or dummy load
is connected, and power cord is putted to the outlet.
CAUTION
Do not turn PA on for at least 2 hours after unpacking it and moving in its operating
location. Especially when amplifier was moved from a cold place to a warm one, because
not visible condensation may develop inside,and this could result in damage of the PA.
CAUTION
Before switching PA on, check connections between PA and TCVR.

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CAUTION
Never try to change antenna during a transmission to avoid warranty loss.
5.1. Operation Elements
There is couple of operational elements accessible and visible on the front panel.
STBY - Standby mode LED
OPERATE - Operation mode LED
CW - CW mode LED
PREAMP - Preamplifier „ON“ LED (+12V control voltage output)
FAULT - Failure LED
ON AIR - Transmitting mode LED

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OPER - short press to switch between Standby and Operation mode
SET -long press (about 2,5 seconds) to enter the Settings menu (green LED is ON)
-short press to release the Settings menu (green LED is OFF)
-short press to confirm parameters in the Settings menu
-short press to move cursor to the right in editing mode
-long press to release editing mode and confirms Own text
PRE - short press to switch preamplifier ON and OFF
-short press to start editing mode in the Settings menu
-short press to move cursor to the left in editing mode
CW/SSB - long press to change between CW (CW LED is ON) and SSB mode (LED is OFF)
UP–DWN - short press to list in LCD menu
- short press to change parameters
- short press to scroll trough the alphabet in editing mode
UP - long press to enter Hardware SETTINGS menu – not available for users
- short press to release the SETTINGS menu
5.2. Preparation for operation
After turning on the power switch on the front panel power amplifier will automatically go
into standby mode.
NOTE
Some of next preparation steps are accessible only in standby mode.

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5.2.1. Display Menu
The graphic display shows couple of parameters or texts. In every line user can select
different ones, using UP/DWN buttons (UP for upper line scroll, DWN for bottom line
scroll) :
OM POWER amplifier - Own text – Bar graph for output power – PWR in watts +
short bar graph - PWR in watts + REF in watts – PWR in watts + SWR – Pin in watts
+ SWR – T1 in deg C – Um1 in Volts + Im1 in Amps – OM POWER amplifier - ……..
Have a look at some of combination examples:

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5.2.2. Settings Menu
Press SET button for about 2,5 seconds to enter Settings menu. Green LED in the button’s
corner will light. The top line will display „Settings menu“, in the bottom line user can scroll
these parameters or texts:
Own text – Display delay – Bias delay – Preamplifier delay – Bias SSB No.1 – Bias CW
No.1 – Software version x.x – Own text - ………
Use UP/DWN button to select desired parameter for editing or viewing.

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5.2.2.1. Own text editing
„Settings menu“ appears in the upper line. Select „Own text“ in the bottom line. To open
editing mode press PRE.
Cursor will appear in the first position. You can move it to the right using SET, or to the left
using PRE. Insert proper letter or number in the chosen start position using UP/DWN keys.
Move cursor to the next position and then insert next letter, number, sign or space......etc.
Maximum 20 characters.
When you finish editing, press the SET button for about 2,5 seconds to confirm new text and
to leave editing . New text replaces the original „Own text“ in the Display Menu.
5.2.2.2. Display delay
Display delay is the period during which the display remains lit when the PA will remain at
rest (in standby mode for example). The default value is 140 seconds.
„Settings menu“ appears in the upper line. Select „Display delay“ in the bottom line. To open
editing mode press PRE.
To change time use UP/DWN keys. Value can be changed in 20 seconds steps. Confirm the
selected value by pressing SET.

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5.2.2.3. Bias delay
Electronic Bias Settings (EBS) is one of significant feature of the power amplifier. It allows to
set low drain current after pressing the PTT regardless of whether you have CW or SSB
mode, until RF signal is no present at the input. At the moment when RF signal comes to the
input of PA, bias will automatically change its value depending on the selected operation
mode. For CW it will stay low (Id = 200mA), for SSB it will move operating point to AB
class ( Id = 2,7A)...... EBS is default activated – Bias delay is set to ON.
To deactivate EBS you have to set Bias delay to OFF. I such a case bias value after pressing
the PTT will depend on the working mode.
„Settings menu“ appears in the upper line. Select „Bias delay“ in the bottom line. To open
edit mode press PRE. Use UP/DWN buttons to change status. Press SET to confirm new
value and to leave editing.
5.2.2.4. Preamplifier delay
You can control switching of an external RX preamplifier from the PA using PRE button in
operation mode. For reliable working condition and safety of preamplifier there is important
to set some delay of its switching according to the PTT. Possible range is from 0 to 255ms.
Default value is 20 ms.
„Settings menu“ appears in the upper line. Select „Preamplifier delay“ in the bottom line. To
open edit mode press PRE. Use UP/DWN buttons to change value. Confirm the selected
value by pressing SET.

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5.2.2.5. Bias SSB No.1
This parameter will be checked without the possibility to change it. When „Settings menu“
appears in the upper line, select „Bias SSB No.1“ in the bottom line. To view SSB Bias press
PRE. In couple of seconds you will see the value of drain current in the second line (about
2,7A). Do not leave this status active long time. Use the SET button to release checking.
5.2.2.6. Bias CW No.1
This parameter will be checked without the possibility to change it. When „Settings menu“
appears in the upper line, select „Bias CW No.1“ in the bottom line. To view CW Bias press
PRE. In couple of seconds you will see the value of drain current in the first line (about
0,2A). Do not leave this status active long time. Use the SET button to release checking.

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5.2.2.7. Software version
The last thing you can view in the Settings menu, is Software version, visible in the second
line of the display.
NOTE
Do not forget to leave Settings menu by pressing the SET button. Green LED in the button’s
corner turns OFF.
5.2.3. Operating mode
CAUTION
In STBY the amplifier is in bypass-mode and your transceiver is directly connected to
the antenna. Maximum allowed power in bypass mode is 100 Watts! Passing RF power
is not measured and displayed if PA is either in standby mode or turned OFF.
Push the OPER button to activate operation mode. At that moment 50V DC will be
connected to the MOSFET.
In the OPERATE mode you can select CW or SSB transmitting mode, you can scroll Display
menu and select switching of an external RX preamplifier. You can not activate Settings
menu.
NOTE
Setting of CW or SSB mode actually means only a bias adjustment (class C or class AB mode
of PA) and is not strictly tied to the operating mode of the connected transceiver.

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WARNING!
Before you push PTT for the first time, set the RF power in your transceiver to the
minimum (from 3 to 5 watts)!!!
Select parameters in the Display menu as is visible in the previous or next picture and press
PTT. You can check measured parameters of PA.