Japan Radio Co. JSS-2150, Service Manual

Page: 77 / 160

SETUP AND ADJUSTMENT
2-17
2.2.5.5 Tx power adjustment per band
The Tx power for each band (1 MHz to 27 MHz bands) is preset to a rated value with a dummy load
when shipped. After installation check the Tx power for each band and, adjust it if necessary.
z
Pressing ENT on "1. TX band power adj."
displays a popup screen for adjusting the Tx
power as shown on the left.
Remark: Inaccessible in AM mode.
z
Mode
Select from TEL, DSC, CW or TLX.
Remark: Used to select a TX type.
Tx power is saved for the band,
regardless of the communication
mode.
z
PWR
Select either High (rated power) or Low* to
adjust the Tx power.
* Low power is 50W for HF and 33W for MF.
z
Frequency
Input a frequency for each band.
* if not tuned,
TUNE is displayed at PWR.
Press the ANT TUNE key at that time.
z Type
Select a TX type for the communication mode.
‚
TEL: Test tone/MIC
‚
DSC: 1615Hz/1785Hz/Dot
‚
TLX: 1615Hz/1785Hz/Dot
‚
CW: (setup unnecessary)
z TX power
Can be set between 0.5 to 200.0% of
typical (100%).
Note1. The upper and lower limits might be
refused by the PA limiter.
Note2. TX power can be set at 0.5% steps.
z
[TX]
Starts transmitting by the conditions above.
‚ During the transmission, this handling
menu changes to [Stop]. Press ENT
again to stop the transmission.
‚
According to the communication mode,
the PTT or CWKEY is available.
‚
During the transmission, PA voltage (Vc),
PA current (lc), antenna current (la), and
standing wave ratio (SWR-P) are
displayed.
z [Save]
Saves the TX power of the band.
ENT ↓
Note: Based on the PA voltage (Vc)
and PA current (lc) checked here
and the efficiency
η written in
the inspection data attached to
the equipment, the Tx power
(antenna power) P is calculated
as follows.
P = Vc x lc x
η
So check that P is within ±20%
to the rated power.
Additionally, when Tx power is
adjusted to an over-power, the
circuit protection may reduce the
Tx power to low. In this case,
press ANT TUNE key to retune
and adjust the Tx power again.