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- check the good working order of the coaxial cables, connectors, and feed lines from the
transceiver antenna jack through the amplifier, the antenna switch or external tuner (if there is
one) to the BALUN transformer, and the antenna itself (S. 2-3(e)).
If the power and SWR are as expected, transmit again and while watching the power and the SWR
readings, increase transceiver power gradually from minimum to maximum (but not more than 200W in
order to not overload the RF by-pass circuit of the amplifier).
If SWR remains below 2:1 (preferably below 1.5:1) at the last test, decrease the power from the
transceiver to minimum again and continue with the next check-up.
b) Check-up in Stand-by mode.
Turn the amplifier on, as described in Sections 3-1 to 3-4 (Fig. 3-2).
Make sure that the amplifier is in Stand-by mode. Push the OPR/STB button if needed.
Repeat receive and transmit tests as it was done with the amplifier turned off. During these tests note
also whether the forward and reflected power bargraph and digital readout (S. 3.4(e),(f)) show respective
RF power presence. If the reflected power exceeds the forward power, verify that the input and output
coaxial cables to the amplifier are not interchanged (S. 2-3(d),(e)).
N O T E
The power indication accuracy is optimized around the 700W level and
usually it is unreliable below 40W.
c) Entering Operate mode.
At Operate mode the transceiver receiving should not suffer. If it worsens and together with this the
indicator RX changes into TX although the transceiver is in receive mode, check the control cable
connected to the KEY-IN input – S. 2-3(b) for a short. The connection to the transceiver could be
wrong too.
d) Test transmission.
Switch to the same band as the transceiver and antenna.
Set the transceiver to a continuous carrier and minimum power. In Operate mode choose a free frequency
and push the PTT or CW key briefly, while watching the amplifier’s behavior:
- RX mode must has changed to TX;
- the reflected power must read below 20W;
- the forward power must read between 20 and 150W with minimum drive power from the
transceiver (between 1 and 5W);
If the above test goes normally, push briefly the PTT once again, this time watching the transceiver’s
SWR reading (i.e. the input SWR of the amplifier) – this must be below 1.2:1.
e) Setting of drive level and typical operation.
After the successful passing of the above tests push PTT or CW key for several seconds, watching
the forward and reflected power. Increase the drive power until the forward power at the amplifier’s
output reaches 700W.
Summary of Contents for 700S
Page 1: ...OPERATING MANUAL ...