// Status=review
.Receiver Noise Level

- If it is not already highlighted in green, click the *Monitor*
button to start normal receive operation.  

- Be sure your transceiver is set to *USB* (or *USB Data*) mode.

- Use the receiver gain controls and/or the computer's audio mixer
controls to set the background noise level (scale at lower left of
main window) to around 30 dB when no signals are present.  It is
usually best to turn AGC off or reduce the RF gain control to minimize
AGC action.  If necessary you can also adjust the slider next to the
dB scale, but note that the overall dynamic range will be best with
this slider not too far from its mid-point.

.Bandwidth and Frequency Setting

- If your transceiver offers more than one bandwidth setting in USB
mode, you should normally choose the widest one possible, up to about
5 kHz.  This choice has the desirable effect of allowing the *Wide
Graph* (waterfall and 2D spectrum) to display the conventional JT65
and JT9 sub-bands simultaneously on most HF bands.  Further details
are provided in the <<TUTORIAL,Basic Operating Tutorial>>.  A wider
displayed bandwidth may also be helpful at VHF and above, where JT4
and JT65 signals are found over much wider ranges of frequencies.

- If you have only a standard SSB filter you won’t be able to display
more than about 2.7 kHz bandwidth.  Depending on the exact dial
frequency setting, on HF bands you can display the full sub-band
generally used for one mode (JT65 or JT9) and part of the sub-band for
the other mode.

- Of course, you might prefer to concentrate on one mode at a time,
setting your dial frequency to (say) 14.076 for JT65 or 14.078 for
JT9.  Present conventions have the nominal JT9 dial frequency 2 kHz
higher than the JT65 dial frequency.  

.Transmitter Audio Level

* Click the *Tune* button on the main screen to switch the
radio into transmit mode and generate a steady audio tone. 

* Listen to the generated audio tone using your radio’s *Monitor*
facility. The transmitted tone should be perfectly smooth, with no
clicks or glitches.

* Open the computer's audio mixer controls for output (``Playback'')
devices and adjust the volume slider downward from its maximum until
the RF output from your transmitter falls by around ten percent.  This
will be a good level for audio drive.

* Alternatively, you can make the Tx audio level adjustment using the
digital slider labeled *Pwr* at the right edge of the main window.

* Toggle the *Tune* button once more to stop your test transmission. 

IMPORTANT: Windows Vista and later incorrectly configure audio devices
using the Texas Instruments PCM2900 series CODEC for microphone input
rather line input.  (This chip is used in many radios with built-in
USB CODECs, as well as various other audio interfaces.)  If you are
using such a device, be sure to set the mic level in the Recording
Device Properties to 0 dB.
