QCX assembly Rev 1.08
99
8.9 Phase Lo
Press Select!
Pressing the left (select) button activates the signal generator on the configured frequency with an
offset to put the received signal in the unwanted sideband at the audio frequency configured (for
example, 600Hz). It displays a bar on the screen showing the measured audio amplitude. The Low
frequency phase adjustment trimmer potentiometer should be adjusted for minimum measured
amplitude. This process is described in the earlier section “Adjustment and alignment” at the end
of the assembly part of the manual.
8.10 Phase Hi
Press Select!
Pressing the left (select) button activates the signal generator on the configured frequency with an
offset to put the received signal in the unwanted sideband at the audio frequency configured (for
example, 800Hz). It displays a bar on the screen showing the measured audio amplitude. The
High frequency phase adjustment trimmer potentiometer should be adjusted for minimum
measured amplitude. This process is described in the earlier section “Adjustment and alignment”
at the end of the assembly part of the manual.
8.11 Cal ref osc
Press Select!
If you have connected a GPS receiver module such as the QRP Labs QLG1 GPS receiver
http://qrp-labs.com/qlg1
with a one pulse per second (1pps) output signal, then when you press
the left (select) button the microcontroller uses the 1pps as a frequency counter gate. The 27MHz
reference value is divided by 4 and routed to the Timer1 input of the microcontroller, where it is
counted for 4 seconds to obtain a frequency count. This value is stored in the EEPROM in the
configuration parameter editable in menu item “8.5 Ref frq”.
The firmware calculates compensation adjustments to correct for the frequency error and ensure
an output frequency precisely on target (typically with sub Hz accuracy). Naturally changes in
ambient temperature will also cause the crystal oscillator frequency to change somewhat.
Using the GPS to calibrate the reference oscillator, system oscillator, or GPS info display (see
later section), also automatically parses the serial data stream and sets the real-time clock and the
Maidenhead Locator square (computed from latitude and longitude); these are used by the
Beacon mode when using the radio as a WSPR beacon.
Summary of Contents for QCX 5W CW
Page 9: ...QCX assembly Rev 1 08 9...
Page 10: ...QCX assembly Rev 1 08 10...
Page 12: ...QCX assembly Rev 1 08 12...
Page 50: ...QCX assembly Rev 1 08 50...
Page 105: ...QCX assembly Rev 1 08 105...
