Avionics Bending: VHF/HF COM Radio Integration with X-Plane (Part 8)

As you probably know, navigation aids, such as VOR, DME, ILS and ADF, are identified by Morse code (CW). Typically they are identified by a 3 or 4 letter identifier like: PDK, JFK, CHA, etc. The standard frequency for the CW signals is 1020Hz. However, in some cases NAV aids also carry a voice signal that can give weather or AWOS or other information. In the case of ADF stations, that signal can also be co-located with AM radio stations. So most audio panels provide the ability to "filter" out Morse code to provide a clear and uninterrupted voice signal. To enable this filter most panels, like the one that I use from Gables Engineering, have a "VOICE ONLY" type setting. The audio panel that I am intending to use for the L-1011 simulator has a large orange momentary switch that toggles the CW filter on and off. The video below shows the Voice Only filter for CW in action:

I used the Kennedy VOR (JFK) as the Morse code and the Kennedy International D-ATIS information as the voice ... this is a combination that does not really exist in reality and I just combined them for this demonstration. Just doing a rough measurement it appears the filter covers a frequency range between about 920 - 1120Hz. The filter has very little to no impact on the voice signal, however, the effect on the CW is very obvious.

Below is a quick refresher on Morse Code:

International Morse Code