166.5125 MHz Mysteries

For those who have been into federal monitoring for a while, the frequency of 166.5125 MHz should appear familiar. It has been long known as the White House Communications Agency SIERRA channel, (inside info seems to indicate this now may be known as ALPHA).  It always seemed to be used by the WHCA advance teams when they were in town getting ready for a visit from the VP or POTUS.

However, some reports have this channel active in areas and times when no VIP visits were planned or ever occurred. As I mentioned in my logs of Super Bowl XLVI in Indianapolis, local listeners heard encrypted traffic on this frequency several weeks prior to the Super Bowl. While I guessed that they have have been scouting locations for a possible Super Bowl visit from POTUS, I have heard a couple reports from the Dallas/Ft. Worth area of traffic on this frequency with more activity and longer operations that might be expected from the WHCA. One report heard some clear activity with what sounded like airborne surveillance operations, highly unlikely for the WHCA.

As far as I can tell, the frequency is an exclusive allocation to the WHCA and I've not logged any other agencies operations on this channel. But there might be a possibility that this frequency is in some Secret Service radios and they may just have decided to use it for some of their operations. There has long been an assumption that the Secret Service has some WHCA channels in their radios, as they two agencies often interact on many Executive Protection details.

Clearly, more information is needed. But keep an ear on 166.5125 MHz and see if it gets busy in your area.