To enter Manual mode of the PA please press MAN. By pressing MAN repeatedly you select
BAND and band’s segment You can control the segment or band by scrolling the UP / DWN
buttons.
TUNE
OM2500A 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.
Entering the TUNE mode is done by pressing the TUNE button. OM2500A then switches the
TRX to RTTY and sets the frequency to corresponding segment. By changing the values of
TUNE and LOAD capacitors we tune the PA as per manual tuning instructions (below in next
part of manual) Optimally tuned PA delivers full output without reaching maximum Screen
Current of 30mA!!!
After tuning the PA we save the settings by pressing SET and PA will automatically tune
frequency of TRX to next band segment. Follow the same procedure for all bands and
segments if needed.
By pressing MAN or AUTO buttons PA and TRX will return to standard operating mode.
Deviding of bands into segments
Band (MHz)
1,8 3,5 7
10 14 18 21
24
28
Width of the segments (kHz)
30 40 40 50 50 60 100 100 200
TUNING
The OM2500A 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.
Summary of Contents for OM2500 A
Page 1: ...Instruction Manual OM2500 A SHORTWAVE POWER AMPLIFIER OM POWER s r o 930 30 B 126 SLOVAKIA...
Page 12: ...Example of AUTO mode using ICOM TRX Example of AUTO mode using Kenwood TRX...
Page 15: ...Example of connection for Icom...
Page 16: ...Example of connection for ELECRAFT...
Page 17: ...Example of connection with Yeasu...
Page 19: ...Example of connection with antenna switch and BPF...
Page 24: ...Example of connection PA with Microham MKII MK2R etc with CI V output...
