2015-05-27 19:50:08 -04:00
|
|
|
|
// Status=review
|
|
|
|
|
.Receiver Noise Level
|
|
|
|
|
|
|
|
|
|
- If it is not already highlighted in green, click the *Monitor*
|
2015-11-15 19:11:40 -05:00
|
|
|
|
button to start normal receive operation.
|
2015-05-27 19:50:08 -04:00
|
|
|
|
|
|
|
|
|
- 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
|
2015-11-09 12:21:05 -05:00
|
|
|
|
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.
|
2015-05-27 19:50:08 -04:00
|
|
|
|
|
|
|
|
|
.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
|
2015-05-31 11:58:33 -04:00
|
|
|
|
Graph* (waterfall and 2D spectrum) to display the conventional JT65
|
|
|
|
|
and JT9 sub-bands simultaneously on most HF bands. Further details
|
2015-11-16 15:13:47 -05:00
|
|
|
|
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.
|
2015-05-27 19:50:08 -04:00
|
|
|
|
|
|
|
|
|
- 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
|
2015-05-31 11:58:33 -04:00
|
|
|
|
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.
|
2015-05-27 19:50:08 -04:00
|
|
|
|
|
|
|
|
|
- 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
|
2015-05-31 11:58:33 -04:00
|
|
|
|
higher than the JT65 dial frequency.
|
2015-05-27 19:50:08 -04:00
|
|
|
|
|
|
|
|
|
.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.
|
|
|
|
|
|
2015-11-20 21:34:20 -05:00
|
|
|
|
* Open the computer's audio mixer controls for output ("`Playback`")
|
2015-05-27 19:50:08 -04:00
|
|
|
|
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.
|
2015-11-15 10:01:57 -05:00
|
|
|
|
|
|
|
|
|
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
|
2015-11-16 15:13:47 -05:00
|
|
|
|
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.
|