2015-05-27 19:50:08 -04:00
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// Status=review
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.Receiver Noise Level
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- If it is not already highlighted in green, click the *Monitor*
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button to return to normal receive operation.
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- Be sure your transceiver is set to *USB* (or *USB Data*) mode.
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- Use the receiver gain controls and/or the computer's audio mixer
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controls to set the background noise level (scale at lower left of
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main window) to around 30 dB when no signals are present. You may
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find it best to reduce the RF gain control so as to minimize AGC
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action. If necessary you can also adjust the slider next to the dB
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scale, but note that the overall dynamic range will be best with this
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slider not too far from its mid-point.
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.Bandwidth and Frequency Setting
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- If your transceiver offers more than one bandwidth setting in USB
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mode, you should normally choose the widest one possible, up to about
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5 kHz. This choice has the desirable effect of allowing the *Wide
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2015-05-31 11:58:33 -04:00
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Graph* (waterfall and 2D spectrum) to display the conventional JT65
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and JT9 sub-bands simultaneously on most HF bands. Further details
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are provided in the <<TUTORIAL,Tutorial>> section. A wider displayed
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bandwidth may also be helpful at VHF and above, where usage of JT65
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and JT4 is found over a much wider range of frequencies.
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2015-05-27 19:50:08 -04:00
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- If you have only a standard SSB filter you won’t be able to display
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more than about 2.7 kHz bandwidth. Depending on the exact dial
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2015-05-31 11:58:33 -04:00
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frequency setting, on HF bands you can display the full sub-band
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generally used for one mode (JT65 or JT9) and part of the sub-band for
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the other mode.
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2015-05-27 19:50:08 -04:00
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- Of course, you might prefer to concentrate on one mode at a time,
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setting your dial frequency to (say) 14.076 for JT65 or 14.078 for
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JT9. Present conventions have the nominal JT9 dial frequency 2 kHz
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2015-05-31 11:58:33 -04:00
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higher than the JT65 dial frequency.
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2015-05-27 19:50:08 -04:00
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.Transmitter Audio Level
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* Click the *Tune* button on the main screen to switch the
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radio into transmit mode and generate a steady audio tone.
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* Listen to the generated audio tone using your radio’s *Monitor*
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facility. The transmitted tone should be perfectly smooth, with no
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clicks or glitches.
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* Open the computer’s audio mixer controls for output (``Playback'')
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devices and adjust the volume slider downward from its maximum until
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the RF output from your transmitter falls by around ten percent. This
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will be a good level for audio drive.
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* Alternatively, you can make the Tx audio level adjustment using the
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digital slider labeled *Pwr* at the right edge of the main window.
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* Toggle the *Tune* button once more to stop your test transmission.
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