11
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 OM4001A 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 20-21 for more details.
