10
applied (cold switching). Modern transceivers they have a time delay between PTT switching
and power output.
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 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)
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 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 speed is setting automatically according to the tube temperature. If the tube
temperature is below 40 deg. Celsius, the blower speed is minimal (abt. 18 %). Between 40
degrees and 80 degrees Celsius the speed is rising from 19% to 100% of maximal RPM.
Detailed view on the tube and blower
area. Antenna switch is installed inside
the metal box.
