R1.1
Copyright © 2016 SDRplay Limited
19
SDRuno User Manual
-
SLOW: this is definitely the DX choice; lock time is slower and the PLL is much more immune to
noise. This mode combined with a narrow PLL BW filter setting gives exceptional lock stability on
very noisy signals.
Locking range is limited with this setting: if this is a problem, first select FAST mode then switch to SLOW
if required.
The pre-PLL pass-band filter can be adjusted from +/- 50 Hz to the full bandwidth available. Please note
that this setting also limits the range in which the PLL can achieve lock: for example if you are using a 500
Hz setting (default) and you tune outside the +/- 500 Hz from the carrier, the PLL will never lock as the
carrier is filtered out.
All the PLL AGC parameters are pre-fixed for best results minus the release time. This parameter can be
optimized for the specific reception condition; usually the default value works well.
All the SAM settings are available in RX Control->Settings->SAM/HP Tab.
6. Frequency calibration
In SDRuno the hardware frequency calibration can be done manually in Main Window->Settings->Cal or
automatically in the VRX Control Window->Settings->Cal. For manual calibration, you can input a value in
Parts Per Million; that value will be positive if the hardware oscillator is lower than its nominal frequency or
negative otherwise. You can do the calculation of the compensation value at any frequency but best
accuracy is achieved using the upper tuning range of the hardware. You need a reference signal whose
frequency is known and accurate (for example in HF could be WWV on 15000 KHz).
Let’s see an example using CHU (14670 KHz) as reference:
-
Using the Aux Spectrum window with a high zoom factor tune carefully the reference signal until
you have the carrier at 0 Hz in the spectrum.
-
Read the frequency indicated on the dial. In this example it is 14670082: this means that the
reference oscillator in your hardware is lower than its nominal value.
-
Compute the error as 14670082
– 14670000 = 82 Hz.
-
Compute the PPM compensation value as 82 * 1000000 / 14670000 = 5.590
-
Insert the above value in the HW LO Freq. Calib. edit box and press the Enter key.
-
Retune the reference frequency and check that the calibration is effective.
For automatic calibration, follow the instructions within the VRX control window->Settings->Cal panel.
7. S-Meter calibration
SDRuno automatically calibrates both the power measurement and the S-Meter for the RSP device.
Additional external gain or loss can be set in Main Window->Settings->CAL->EXTERNAL FRONT END
GAIN.
