I have been working on creating a TACAN navigation module for FSX. I'm using a very simple method, simply mapping TACAN channels to VOR frequencies. This allows the use of the existing FSX system and existing VOR navaids. Another benefit is additional navaids could be added by using existing scenery tools. What I am creating is the underlying system and not the gauges. The module is a FSX dll that is loaded at start-up through the dll.xml file. It provides the following variables to a gauge programmer: Code: C:TACAN:Channel C:TACAN:XYMode C:TACAN:SignalStrength C:TACAN:Bearing C:TACAN:Distance Channel (000 - 126) and XYMode (0 or 1, where 0=X and 1=Y) are writeable values and specify the TACAN channel to be tuned. SignalStrength, Bearing and Distance are read-only vars that provide the navigation information. These values are simply re-routed from the NAV2 data. This provides gauge creators with a simple interface to implement TACAN navigation in military aircraft for FSX. I'd welcome any suggestions to improve the system, and any gauge creators to help test it. You can see by my test gauge I'm no artist! Thanks to Bill Leaming for the radio tuning code!