Table of Contents
Advertisement
7. Transmit operation
ATTENTION !
This device is for split line operation only. There is no
output relay inside. Separate cables for TX and RX must be used. An
external output relay can be used with the internal sequencer. SEE Chapter
Remote control for more details.
The RX/TX-switching is activated by applying zero volts or ground to the
"PTT" or pin 6 of the "CONTROL"-jack on the rear panel and will be
indicated by the illuminated green "PTT"-LED. On most transceivers this
voltage is supplied separately by an accessory output on their rear panel.
The internal input coaxial relays is controlled with a different time delay to
allow for it's specific switching time and achieve zero power switching.
The internal control circuit also provides a sequence controlled switching of an
external antenna relay instead of the missing output relay inside. On pin 2 of the
"CONTROL" jack a voltage of 14 VDC is provided. It is short circuit protected
by use of a 1,25A PTC-fuse.
The PTT line is also used to generate the bias voltage to run the MOSFETs in
class AB. Without RF input the total idle current is 4 A, equivalent to dissipating
200 watts. An internal generated and delayed PTT- function is available at the
inner contact of the rear sided "AUX"- jack to reliably control a connected
transceiver. Any potential at the inner conductor is switched to ground.
In essence, your amplifier provides a built-in multi-level sequencer which
provides an alternate means to key your radio last.
When the amplifier PTT is activated usually via a foot switch, the preamp
voltage is dropped first, internal relays are switched, the RF amplifier section is
turned on and finally via the AUX jack a ground on transmit is available to key
your radio.
When using SSB you should not exceed 2,5 watts of input power to achieve best
spectral purity with low inter-modulation distortion. A red LED indicator
integrated in the front panel power meter indicates the 1 dB compression point
limit at 800 watts. Exceeding this limit will cause harmonic distortions to be
transmitted. An integrated peak-hold function provides a more effective
indication of the output power.
10
Advertisement
Table of Contents
