ADJUSTMENT PROCEDURE

Table 6-1 VHF Test Frequencies

Test Channel

Tx/Rx Freq

Power

Call Guard

Bandwidth [1]

(MHz)

Squelch

 

 

 

 

 

 

 

 

1

174.050

Low1

None

Narrow or wide

 

 

 

 

 

2

146.050

Low1

None

Narrow or wide

 

 

 

 

 

3

160.050

High

None

Narrow or wide

 

 

 

 

 

4

160.050

Low2

None

Narrow or wide

 

 

 

 

 

5

160.050

Low1

None

Narrow or wide

 

 

 

 

 

6

160.050

Low1

007N DTCS

Narrow or wide

 

 

 

 

 

7 [1]

160.050

Low1

None

Alternate

 

 

 

 

 

8 [1]

160.050

Low1

007 DTCS

Alternate

 

 

 

 

 

[1] If the transceiver operates on only narrow or wide band channels, program only chan- nels 1-6, and program them for the type of channels used (narrow or wide band). If the transceiver operates on both wide and narrow band channels, program additional channels 7 and 8 for the other type of operation.

Table 6-2 UHF Test Frequencies

Test Channel

 

Model (see Section 1.4)

 

Power

Call Guard

Bandwidth [1]

400-430 MHz

450-470 MHz

470-490 MHz

488-512 MHz

Squelch

 

 

 

1

400.050

450.050

470.050

490.050

Low1

None

Narrow or wide

 

 

 

 

 

 

 

 

2

430.050

470.050

490.050

512.050

Low1

None

Narrow or wide

 

 

 

 

 

 

 

 

3

400.050

450.050

470.050

490.050

High

None

Narrow or wide

 

 

 

 

 

 

 

 

4

400.050

450.050

470.050

490.050

Low2

None

Narrow or wide

 

 

 

 

 

 

 

 

5

400.050

450.050

470.050

490.050

Low1

007N DTCS

Narrow or wide

 

 

 

 

 

 

 

 

6 [1]

400.050

450.050

470.050

490.050

Low1

None

Alternate

 

 

 

 

 

 

 

 

7 [1]

400.050

450.050

470.050

490.050

Low1

007N DTCS

Alternate

 

 

 

 

 

 

 

 

[1] If the transceiver operates on only narrow or wide band channels, program only channels 1-5, and program them for the type of channels used (narrow or wide band). If the transceiver operates on both wide and narrow band channels, program additional channels 6 and 7 for the other type of operation.

6.1.4 COMPUTER-AIDED TUNING

To make most adjustments described in the fol- lowing information, the computer setup used for pro- gramming (see Section 4) and special Adjust software are required. The Adjust software is included on the disk with the programming software in a separate sub- directory called ADJ. To set up the transceiver for use with this equipment, proceed as follows:

1.Copy the Adjust software to the hard disk or a pro- gramming disk as described in Section 4.1.3

2.Turn transceiver power on and connect the com- puter to the transceiver microphone jack using the programming cable and fabricated test cable described in the preceding section (see Figure 6-1).

3.Start the computer in the DOS mode. Make the cur- rent directory the ADJ subdirectory and start the program by typing the following:

ADJUST /X /Y

X = A - VHF (normal crystal), B - UHF (TCXO) Y = 1 - Serial port 1, 2 - Serial port 2

For example, if tuning a VHF transceiver and the programming cable is connected to serial port 2 of the computer, type ADJUST /A /2 (ENTER).

4.The tune data in the connected transceiver is then downloaded and the adjustment screen shown in Figure 6-2is displayed. The information displayed

 

November 1998

6-3

Part No. 001-7600-001

Page 58
Image 58
EFJohnson 764X, 761X service manual VHF Test Frequencies, UHF Test Frequencies, COMPUTER-AIDED Tuning