TKR-750
45
Item
Condition
Measurement
Adjustment
Specifications/Remarks
Test-
equipment
Unit
Terminal
Parts
Unit
Method
ADJUSTMENT
Confirmation and Alignment of Set-up to
Prevent Receiver Desensitization
1.
Confirmation of Duplexer alignment
The duplexer allows the Repeater to simultaneously trans-
mit and receive. To accomplish this, in the programmed re-
ceive frequency, the transmit frequency must be notched or
suppressed by 75dB or more. Additionally, on the pro-
grammed transmit frequency, the receive frequency must be
notched or suppressed by 75dB or more. The following fig-
ures are examples of Duplexer alignment using a spectrum
analyzer.
Ref –10dBm
# Peak
Log
10dB/
Atten 5dB
V1 V2
V3 FC
AA
#Res BW 30kHz
VBW 30kHz
Span 20MHz
Sweep 50ms (401 pts)
RX
TX
75dB or more
2.
Confirmation of Repeater Desensitization
The following figure is a Test set-up for Repeater Desensi-
tization.
After this Test set-up is completed, confirm the Repeater
Desensitization as mentioned below.
1) Disable the repeater mode.
2) Adjust the level of the RF generator until 12dB SINAD is
reached.
3) Increase the output of the RF generator by 1dB. (This in-
creases the SINAD.)
4) Enable the repeater mode.
5) Read the SINAD level. It should not drop below 12dB
SINAD. If the SINAD is less then 12dB, check the tight-
ness of the connectors and the tuning of duplexer.
50
Ω
dummy
RF signal
generator
Duplexer
Repeater
Attenuated
port
35. Repeat
1) VCO-A CH (TX VCO A center) SSG
Rear
RX ANT
PC adj.
±
0.1kHz
gain level
VCO-B CH (TX VCO B center)
1kHz
(Wide)
SSG output : –53dBm
MOD ANA
TX ANT
SSG MOD : 1kHz
or
SSG DEV : 1kHz
Deviation
Deviation meter filter
meter
HPF : OFF
Oscilloscope
LPF : 15kHz
De-emphasis : OFF
Transmission
(Narrow)
2) VCO-A CH (TX VCO A center)
VCO-B CH (TX VCO B center)
Transmission
When “RF Power Down Detect” is programmed in the AUXO function, threshold of transmission output is set with the following menu.
36. Power
1) CH : 2 (High power)
Power meter Rear
TX ANT
PC adj.
down detect
About 20W
(High)
(Factory-default)
(Low)
2) CH : 2 (Low power)
PC adj.
About 10W
(Factory-default)