416.500 mHz?

[dannyg]

I usually have a near-field receiver running here, and today a strong signal appeared out of the blue on 416.5. I verified on my scanner that it was a real signal (not an image), and it was blasting in at over +40dB. This was mid-afternoon, but I remember encountering this late one evening many months ago. The signal had no modulation I could hear in AM or FM (various IF bandwidths), and stayed solid (just a few dB of signal strength variation over time) for about 20 minutes, and then abruptly disappeared.

Any help in identifying the source or agency would be appreciated.

I'm located on the San Mateo Country coast, within view of the Pillar Point tracking station, if that's any help.

 

[kb5udf]

Possibility

Found a document referring to a steady carrier on this frequency being used for rocket launch command destruct systems: http://www.fas.org/spp/guide/usa/facility/wallops.pdf