Operating instructions

LOCAL OPERATION
3-20 46882-311D
Manual frequency setting
Range; 100 kHz to 1.05 GHz
With the
legend highlighted, data can be entered from the keyboard to the Tx FREQ
parameter. As the entry can only be a frequency setting, it is not necessary to select the orange
[FREQ] key. Enter the required frequency by using the digit keys and the decimal point key if
relevant. The resolution of the RF FREQ entry is 1 Hz, but it is not necessary to enter every digit
down to the least significant place if a ‘multiplier’ terminator key is used.
The entry is completed by pressing a terminator key. Using the [MHz], [kHz] or [Hz] key causes
the entered frequency to be displayed according to normal convention. The following examples
explain further.
Pressing:-
[1] [2] [5] [MHz] will display 125.000000 MHz
[1] [2] [5] [kHz] ” “ 125.000 kHz
[1] [2] [5] [0] [kHz] ” “ 1.250000 MHz
[1] [.] [2] [5] [MHz] ” “ 1.250000 MHz
[1] [2] [5] [0] [0] [0] [1] [Hz] ” “ 1.250001 MHz
Variable control
With the
legend highlighted, the Tx FREQ parameter can be adjusted by using the
variable control.
Frequency increment
The FREQ [
] and [ ] keys can be assigned to transmitter frequency adjustment. Refer to the
section on incremental adjustments which starts on page 3- 62.
Automatic frequency setting
Pressing the [Auto Tune] key causes the Service Monitor to sweep over the RF input range and
lock onto the strongest signal present on the selected RF input socket. The mean frequency of the
signal is displayed against the
Tx FREQ
legend, with
Auto tune
replacing
OFFSET.
SSB (if fitted). The autotune function may not operate when attempting to tune to an SSB
transmitter unless a steady tone is being used as a modulation source. The frequency to
which the Service Monitor will tune will be the true RF frequency of the sideband and not
that of the channel frequency.
Pressing the [Rx=Tx] key causes the RF generator used for the Rx TEST mode to be set to the
same frequency as the measured RF from the transmitter under test. A frequency offset facility
can be set up which gives a set difference between the frequency of the measured transmitter RF
and the set frequency of the receiver test generator. (Rx=Tx ± offset). See the option selections
within setup page 1, for more information.
After setting the Tx FREQ and any associated adjustments, use the [Return] key to revert to the
original TX TEST menu.
Tx power
The [Tx Power] key gives access to RF power measurement functions or associated functions.
Broad Band or Narrow Band power
The [Broad/Narrow] key selects which of the RF power measurement methods is operative. The
selected method is indicated on the display by the letters BB or NB to the right of the digital
power reading. The use of this facility is explained under Making measurements later in this
chapter, starting on page 3- 25.