Datastorm Users

Turning Cross-Pol on and off with the Datastorm

by Don Bradner

Some starting points:

1. Cross-Pol is very important, because a badly aligned transmitter will cause undue interference. Cross-Pol measurements are a good thing.

2. The Datastorm does such a good job of aligning skew that it would be very unlikely for a Datastorm to be very far out of alignment.

3. The Cross-Pol servers at Direcway are a weak point in the system. They are frequently overloaded, and that is the case at the time of this writing (5/31/2005).

4. When the servers are overloaded, you wind up in a queue that can add very long times to the pointing process. That includes both manual and automatic cross-polling.

For the Datastorm D2 controller, there is a documented method for controlling whether the controller calls for a cross-pol or not. It is found in Configuration, and is a setting for "Optimization." Values possible are None, Partial, and Full. Partial is the default, and in this setting the controller will try a couple of Automatic tests and only go to manual if the tests don't pass. Full will always start with a manual test, and None will turn control over to the modem as soon as pointing is completed.

There is no documented method for turning off cross-pol on the D1 controller, but there is an undocumented one that involves a registry change. Not being subject to the constraints that Motosat must work under, I'm releasing here a couple of .REG files that will turn off (disable) and turn on (enable) cross-pol. You can download them here:
disable_x_pol.reg
enable_x_pol.reg

Save these files to your computer for use as needed.
Instructions: Before you can disable cross-pol, you must be in a cross-pol completed situation, which means you are online. Click the disable_x_pol file, and then reboot your computer to get the Datastorm software to recognize it.

Notes: It is entirely possible (but not frequent) that the modem will choose to cross-pol on its own. If that happens and you don't pass, you will want to use the enable_x_pol file, reboot the computer, and click Find Satellite again to get the Datastorm software to perform a cross-pol.

It is also strongly advised that you enable cross-pol when there are not known problems at Direcway.