Elecraft P3 High-Performance Panadapter Manual - Manual (Page 31)

31
Calibration Procedures
Frequency Calibration
The P3 requires no calibration for normal
panadapter operation. However if additional
frequency accuracy is desired, you can perform the
following calibration procedure.
Turn the transceiver and P3 on and allow
them to warm up for 30 minutes, minimum,
before performing the calibration.
 If the transceiver has a calibration procedure to
correct its frequency errors, perform that
procedure first.
 Using a well-calibrated signal generator or an
on-the air carrier signal of known frequency,
tune in the signal on the transceiver. An A.M.
broadcast station can serve as a suitable test
signal.
 Adjust the transceiver frequency to the known
frequency of the test signal. Depending upon
the modulation mode of the transceiver, the
signal may not be audible.
 Set the P3 to tracking mode via
MENU:FixTrack, set the span to minimum, and
adjust the reference level and scale so you can
easily see the signal.
 Hold
C E N T E R
twice to remove any center
frequency offset that may have been introduced.
 Select
MENU:Ref Cal
, tap the
SELECT
knob, and adjust the frequency calibration until
the carrier is centered horizontally on the
display. If the required correction is more than a
few hundred units, it may be that the I.F.
frequency is set incorrectly. That can be
adjusted via
MENU:Xcvr Def
.
Amplitude Calibration
The P3 comes with a default amplitude calibration
that works well with a K3 transceiver. Note: If your
K3 was manufactured before September 2009, it
must have the “I.F. Output Buffer Gain
Modification” for the default value to be accurate
(see the note at the top of page 5).
If you have an older K3 without the modification or
you are using another type of transceiver, or if
you’d simply like to optimize the calibration, you
can perform the following calibration procedure.
You will need a signal generator with a calibrated
output level. The recommended frequency is 7040
kHz with an output level of 50 microvolts (-73
dBm). The Elecraft XG2 signal generator will
provide the recommended output and frequency.
Other power levels and frequencies within range of
your transceiver may be used. You’ll need to make
suitable adjustments to the frequencies and levels
given in the following procedure.
 Connect the P3 IF IN to the transceiver’s
i.f. output.
 If using a K3, connect the RS232 cable
between the K3 and P3, turn the
preamplifier OFF, the attenuator ON and be
sure the sub receiver is not enabled.
 Connect the signal generator to the
transceiver antenna input. If using a K3
with the KXV3 option, it is best to use the
RX ANT IN connector to eliminate the
possibility of damaging your signal
generator if you accidentally put the K3 in
transmit. If you use the main antenna
connector and have the KAT3 option
installed, put it in bypass by holding
AT U
until BYPASS appears on the LCD display.
 Set the signal generator for 7040 kHz at a
signal level of 50µV (-73 dBm).
 Put the P3 in tracking mode via
MENU:FixTrack, set the span to 100 kHz ,
and tune the transceiver to approximately
7015 kHz so the signal is centered on the
right half of the display.
 Set the P3 Scale to maximum expansion
(10 dB) and adjust the Ref Lvl to about -78
dBm in order to place the signal peak about
half way up the screen. You may notice a
slight variation in the peak signal level with
small adjustments in the transceiver
frequency as the signal moves from pixel to
pixel on the screen. Adjust the frequency
for maximum reading.