Product manual

Setting FFSK Levels in a Radio-based System
117
Model 6 FFSK Transmit Level
Set the Model 6 Transmit level by performing the following steps. The jumpers on the
Model 6 should be verified initially, prior to setting up the system. See
Table 8 for initial
jumper settings. See
Figure 29 for jumper locations.
♦
Setting the Model 6 transmit FFSK level:
1. At the Model 6, connect the laptop (or PC) to the serial programming port of the
Model 6. Set SW1-8 to ON (places unit in programming mode). Hit the SPACE
bar three times to open the Model 6 Main menu.
2. Enter an “8” to start the FFSK LEVEL SET test tone sequence. The Model 6
should key its radio and transmit for 30 seconds and then unkey. If you finish
making before 30 seconds is up, you can cancel the test by hitting any character
key on the computer keyboard. If you require more time, enter an “8” again.
3. While the FFSK test tone is being transmitted by the Model 6, use the service
monitor to measure the deviation of its radio transmitter. Adjust the R108 pot
(FFSK OUT) on the motherboard of the Model 6 for a deviation of 2.5 kHz
(assuming wide band operation with a full channel deviation of 5 kHz). If the
signal cannot be set low enough, move JP5 in the Model 6 from position TEL to
RAD. If the signal cannot be set high enough, move JP5 from position RAD to
TEL.
4. When finished making adjustments, let the test signal time-out or stop the test.
5. Leave the laptop attached to the Model 6203 and leave it in the programming
mode for now.
Please see the note on radio gain (volume) and roll off (frequency response) on page
113.
Model 26 Receive Sensitivity
Set the Model 26 FFSK Receive sensitivity by performing the following steps. Refer to
Figure 28 for locations and Table 7 for descriptions.
♦
Setting the Model 26 FFSK receive level:
1. Attach an oscilloscope to the FFSK test point (TP6) on the back of the Model 26.
The signal to be measured will be approximately 1.0 Vp-p.
2. On the back panel of the Model 26, turn the 4W RCV pot (R69) fully clockwise
and the 2W RCV pot (R81) fully counterclockwise.
3. Turn the FSK POST RCV pot (R78) fully counterclockwise and set the VOX
pot (R31) to its mid-position.
4. At one of the Model 6 sites that has had its FFSK transmit level set, hit the
SPACE bar on the computer keyboard three times to open the Model 6 Main
menu. Then enter an “8” to start the FFSK LEVEL SET test tone sequence.