Codan Radio Communications VT-3-150-SN User Manual
Enhanced AM/FM Synthesizer Instruction Manual OS(R/T)-3(A/H) 29 - 470 MHz
2-7
In transmitters, the synthesizer operating frequency is the transmitter operating frequency; however,
for receivers, an IF Offset correction factor must be added to or subtracted from the synthesizer
operating frequency in order to determine the actual receive frequency. For VHF and UHF
Receivers, the IF Offset correction factor is 21.4 MHz, while for 800 and 900 MHz Receivers it is
45 MHz. Refer to Channel Designation Table documentation for simplified channel number and
frequency information.
for receivers, an IF Offset correction factor must be added to or subtracted from the synthesizer
operating frequency in order to determine the actual receive frequency. For VHF and UHF
Receivers, the IF Offset correction factor is 21.4 MHz, while for 800 and 900 MHz Receivers it is
45 MHz. Refer to Channel Designation Table documentation for simplified channel number and
frequency information.
2.4.2
Frequency Select Handle Frequency Control
In AM Receiver and Transmitter modules so equipped, the Frequency Select Handle (FSH)
replaces the normal Front Panel handle and allows direct Front Panel selection of the operating
frequency. Operation of the FSH is enabled by setting all external CHANNEL SELECT lines to
‘1111’ (i.e. all lines jumpered to +9.5 Vdc). The FSH user interface consists of three pushbuttons
plus an 8-digit dot matrix display. The FSH module communicates with the synthesizer through a
standard 2-wire serial interface (9600 Baud, 8 bits, no parity, 1 stop bit) using simple ASCII
command protocols. On power up or on any key press, the synthesizer is interrogated by the FSH
for the current channel number and corresponding channel frequency, and this information is then
briefly displayed on the FSH display. The frequency may be either incremented or decremented
from the displayed value by pressing the Frequency Increase È or Frequency Decrease Í
button, as appropriate. For more detailed operating information, refer to the "Frequency Select
Handle Instruction Manual".
replaces the normal Front Panel handle and allows direct Front Panel selection of the operating
frequency. Operation of the FSH is enabled by setting all external CHANNEL SELECT lines to
‘1111’ (i.e. all lines jumpered to +9.5 Vdc). The FSH user interface consists of three pushbuttons
plus an 8-digit dot matrix display. The FSH module communicates with the synthesizer through a
standard 2-wire serial interface (9600 Baud, 8 bits, no parity, 1 stop bit) using simple ASCII
command protocols. On power up or on any key press, the synthesizer is interrogated by the FSH
for the current channel number and corresponding channel frequency, and this information is then
briefly displayed on the FSH display. The frequency may be either incremented or decremented
from the displayed value by pressing the Frequency Increase È or Frequency Decrease Í
button, as appropriate. For more detailed operating information, refer to the "Frequency Select
Handle Instruction Manual".
2.5
Synthesizer Base and Frequency Increment Table
The OS-3A/H Synthesizer operates in frequency increments of 5.0/6.25 kHz, 12.5 kHz or 25 kHz
depending on the particular model and band of operation. The Base Frequency for any given
synthesizer model is the lowest frequency generated.
depending on the particular model and band of operation. The Base Frequency for any given
synthesizer model is the lowest frequency generated.
Model Number
Freq. Range
Base Frequency
Freq. Increment
OST-3H035
29 - 38 MHz
29 MHz
5.0/6.25 kHz
OST-3H045
38 - 50 MHz
29 MHz
5.0/6.25 kHz
OSR-3H061
50.4 - 71.4 MHz
50.4 MHz
5.0/6.25 kHz
OST-3A128
118 - 138 MHz
118 MHz
25/8.333 kHz
OSR-3A149
139.4 - 159.4 MHz
139.4 MHz
25/8.333 kHz
OST-3H141
128 - 152.6 MHz
128 MHz
5.0/6.25 kHz
OST-3H162
150 - 174 MHz
150 MHz
5.0/6.25 kHz
OSR-3H141
128 - 153 MHz
128 MHz
5.0/6.25 kHz
OSR-3H162
150 - 174 MHz
150 MHz
5.0/6.25 kHz
OST-3H418
406 - 430 MHz
406 MHz
12.5 kHz
OST-3H460
450 - 470 MHz
406 MHz
12.5 kHz
OSR-3H440
427.4 - 451.4 MHz
427.4 MHz
12.5 kHz