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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. The relays
of the OM2501A have to be switched earlier than HF is applied (cold switching). Modern transceivers
they have a time delay between PTT switching and power output.
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. If there is possible to adjust TX delay
in your TCVR, set the delay to 15ms, please.
The amplifier is equipped with 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 /2mA)
KEY OUT
RCA Phono - Output signal PTT (maximum switching of 30V / 50mA)
See section 7.9. for Control and ANT/BPF connector PIN-OUT.
Be sure that your power system is correctly wired and properly rated! To use an
adequately sized and connected grounding system is also very important!
4.4. Cooling
The amplifier must be installed in such a way that free flow of hot air from the tube is
allowed. Do not obstruct air intake and exhaust areas of the PA.
The centrifugal blower provides the necessary cooling of the amplifier, even during long contests. The
blower is activated by switching the PA on and it is turned off when cooling is finished (approx. 1-5
min after switching off the PA depending on the temperature of the tube). Blower working mode is
programmable (3 modes). See page 19 for more details.
