Related Manuals for OM POWER OM3500A
Summary of Contents for OM POWER OM3500A
- Page 1 Instruction Manual OM3500A SHORTWAVE POWER AMPLIFIER OM POWER, s. r. o. 930 30 Báč 126 SLOVAKIA...
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Page 2: Important Safety Instructions
• The amplifier contains high voltage circuits. Never turn the amplifier on without the upper lid in place. • The OM3500A amplifier is neither to be used in a wet or humid environment nor to be exposed to rainfall. • The amplifier must be installed in such a way that free flow of hot air from the tube is allowed. - Page 3 The linear amplifier OM 3500A is designed for all short wave amateur bands from 1.8 till 29 MHz (including WARC – bands ) and all modes . It is equipped with a ceramic tetrode GU78b. The OM3500A is automatically tuned to operating frequency of your TRX.
- Page 4 The output of the amplifier is a Pi-L circuit. The ceramic capacitor for TUNE and LOAD are divided. This enables the amplifier to be tuned exactly and makes it possible to easily return to the previously set positions after band change. Top view on the opened OM3500A GU78B PWR meter...
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Page 5: Power Supply
POWER SUPPLY Power supply of the amplifier is effected by two 2,5 kVA toroidal transformers. A soft start is realized with the help of relays and resistors. The high anode voltage consists of 8 times 420V and 2A. Each of them has its own rectifier and filter. In the high voltage circuit safety resistors are employed to protect the amplifier against overload. -
Page 6: Main Supply
MAIN SUPPLY: The amplifier is connected to the mains with 2 cables with a EURO end. Each cable is to be switched to another phase of your main supply system! Both of them have to be able to deliver a power of 2.5 kVA ! If you use only one phase, you have to connect both cables to this one phase ! Your main supply has to be able to deliver 5 kVA on this one phase! In this case the power amplifier can’t deliver... -
Page 7: Control Cable
During transmitting the middle pin is connected to the ground. The relays of the OM3500A have to be switched earlier than HF is applied (cold switching). Modern transceivers have a time delay between PTT switching and power output. - Page 8 CI-V - Mono 3.5mm Jack for connection of ICOM TRXs. For successful operation selection of ICOM radio and correct baud rate is important (9600 default) TCVR - DB-9 -serial port RS232 for YAESU, KENWOOD, ORION ELECRAFT TRXs. Correct baud rate and TRX type is a must for successful operation.
- Page 9 ANT & BPF SW - r DB-25 is used for switching of external HP BPF or external Antenna Switch. Maximum switching of 30V / 0.5A is possible. PIN OUT: 1. antenna port 1 2. antenna port 2 3. antenna port 3 4.
- Page 10 Operation Operating elements (see photo) TUNE - Anode capacitor for tuning, tuning of higher frequencies to "0", Lower frequencies to „100“. LOAD Output capacitor tunes antenna load resistance to amplifier. Capacity is low at „100“ and high at "0" on the scale. OFF - You switch off the amplifier by pressing this button.
- Page 11 INHIBIT – indicates interruption of operation during the tuning process of the PA. If indicated by RED LED then PA is in STBY mode. If retuning within same BAND then PA will retune according to QRG of TRX. When changing the BAND –...
- Page 12 PA will be connected in the following configuration: JST-245<>= DB37- JST-245 cable <> MKII ( or other device from microHAM , which has a CI-V output ) <> PC , OM3500A is connected to the CI-V output of a microHAM device. Example of communication...
- Page 13 If TRX is not connected or communication settings are incorrect the message COMMUNICATION LOST will be displayed. You can still use PA by entering MANUAL mode (MAN Button) or by fixing the communication problems Example of Communication loss message TRX support settings Press SET button and scroll using UP / DWN to CHOOSE TCVR...
- Page 14 Confirm CHOOSE TCVR by pressing SET again and scroll UP / DWN to desired TRX Type. Confirm the selection by pressing SET Continue by selecting Baud Rate Below – Baud rate for TRX – PA communication displayed by OSD By scrolling UP / DWN select desired Baud Rate which must be same as baud rate used by connected TRX.( please refer to your TRX user guide)To confirm your selection press SET.
- Page 15 Example of connection for Icom...
- Page 16 Example of connection for ELECRAFT...
- Page 17 Example of connection with Yeasu...
- Page 18 Example of connection TCVR with Microham MKII, (MK2R+ etc )
- Page 19 Antenna Switching Menu If you have 3 party external antenna switch connected to PA ( i.e. Microham TEN SWITCH) you need to configure assignment of each port to specific band/antenna. By pressing SET and scrolling to ANTENNA SETTINGS and confirming by SET you get current band and its antenna selection.
- Page 20 Example of connection with antenna switch and BPF...
- Page 21 Bandpass filter switching Switching of external band pass filters is automatic and needs to follow pin out of BPF connector. For more see section ANT & BPF Switching Loading factory default settings In rare case of need to restore factory default settings press SET and scroll using UP / DWN to LOAD DEF VALUES and confirm by SET.
- Page 22 Example for connection with another accessories , for example USB micro KEYER II with IC7800 and IC7700...
- Page 23 Example for connection with another accessories , for example USB micro KEYER II with another Icom’s...
- Page 24 Example for connection with another accessories , for example USB micro KEYER II with Yeasu and ELECRAFT...
- Page 25 TX while tuning using ALC control.(mainly while operating FM /RTTY/ AM) ALC Input of your TRX needs to be connected to ALC Out of OM3500A. Using SET and scrolling UP / DWN we select SET MUTE and confirm it by SET. Then we configure MUTE LEVEL for each band so it results in no power being transmitted by TX when performing TUNE procedure.
- Page 26 BAND and band’s segment You can control the segment or band by scrolling the UP / DWN buttons. TUNE OM3500A has been design to deliver maximum output power at 50 Ohms load. To deliver maximum output to real load you need to adjust the tuning according to your real antenna impedance.
- Page 27 TUNING The OM3500 A amplifier is operated in class AB. Thus it’s possible to obtain a maximum output power at an excellent linearity. For this purpose the amplifier has to be tuned carefully. The operation of a mistuned PA will cause malfunctions, the increase of grid current (the GRID- MAX-LED will light up) and problems with TVI/BCI.
- Page 28 Tuning the amplifier to an output of 3000 W OM3500A will tune automatically to either TRX frequency via CAT interface or by frequency sampled by PA. . Reduce the power output of your transceiver to the 0. 2. Switch OPR/STBY to „OPR“ position (OPR LED lights up) 3.
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Page 29: Indication Of Fault Conditions
Should a fault condition appear during the tuning or operation of the amplifier the safety circuits of OM3500A will react. The amplifier will be turned to STBY mode. After approx. 1 sec the control circuits will switch the amplifier back to OPR. If the fault will repeat 3 times after each other the control circuits will turn the amplifier to STBY.
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