Offset calibration for LDR

XDR is the dB value of the relative gain between the co- and cross-receiver channels for LDR measurements. Analogous to GDR, it is defined as the dB value of the ratio of the vertical to horizontal receiver gains, for example:

$X D R = 10 L O G \frac{g_{v}^{r}}{g_{h}^{r}}$ and $x d r = \frac{g_{v}^{r}}{g_{h}^{r}}$

The following techniques are available for calibrating XDR:

Using the Sun to Measure LDR
Using a Signal Generator to Measure LDR
Using a linear feed horn to measure LDR

For all these calibration methods, Vaisala recommends that you

Turn the transmitter off.
Set XDR to 0 dB in the application user software
Configure the RVP10 TTY setups as follows:
- Noise correction enabled for LDR and noise sample taken prior to the measurements (with care not to sample with a test signal turned-on or while looking at the sun).
- Clutter correction disabled for LDR.