User's Manual

12 Tuning the Receiver Front End © Tait Electronics Limited 2005
6. Click Finish. The icon on the Frequency Setup tab indicates that this
task is complete.
Tuning a VHF Receiver Front End
To tune the receiver front end, follow these steps.
1. Ensure you are already connected to the reciter (see “Connecting to a
Reciter Outside the Subrack” on page 5).
2. Select the Frequency Setup tab, and double-click Tune Receiver Front
End. The Tune Receiver Front End Wizard appears.
3. Connect the CTU’s noise source to the receiver input, turn the noise source
on, and then click Next.
4. Click Coarse (fast) and use the tuning tool to roughly adjust the four
front-end trimmers on the receiver. You can do this in any order. As you
do so, observe the graphical RSSI readings across the lock band. Adjust first
for maximum RSSI, and then for flatness.
Note: As the response gets flatter, you may find it helpful to select a
more sensitive scale, so that you can see the graphical reading in
more detail.
5. Once you have roughly tuned the trimmers, click Fine (slow). Repeat the
above procedure until the response is flat in the middle of the lock band and
not more than -1 dB at the ends of the band.
Note: When using the Fine (slow) setting, you may notice a slight
delay as the reading from tuning the trimmers takes approximately
one second to appear on the graph.
6. Click Finish. The icon on the Frequency Setup tab indicates that this
task is complete.
VHF
trimmer holes