Just found this on the web, the Navy funded a research project for " very low 
frequency (VLF) covert acoustic communications". I know that this is for acoustic, 
not rf waves, but the project description reads like the proposed experimental program 
for my Part 5 experimental license!

73 Warren

http://www.nttc.edu/resources/funding/awards/dod/dod971sel/absnavy.asp

DELPHI COMMUNICATION SYSTEMS
30 North Avenue
Burlington, MA 01803
Phone:
PI:
Topic#:         (617) 221-2200
Dr. John G. Proakis
NAVY 97-087
Title:   Covert Underwater Communications
Abstract:   The objective of this project is to develop adaptive channel 
characterization algorithms for very low frequency (VLF) covert acoustic 
communications between submarines and other platforms. Technical issues that 
are addressed are channel propagation conditions in the VLF band and channel 
characterization; the impact of submarine motion on the signals transmitted in 
this band; and determination of optimal propagation conditions. On the signal 
and system level, consideration is given to determining a suitable covert 
signaling strategy; determination and implementation of adaptive signal 
processing methods for use at the receiver, including system initialization and 
tracking aspects.
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73 Warren K2ORS/WD2XGJ
FN42hi