[Milsurplus] NVIS date of discovery

[aGEnuine Ham]

Group:

The last hot topic seems to have died down, so let me start a new one.  I
have seen numerous references, some on this reflector, to the "discovery"
by the military of NVIS in the late 60s - early 70s.  Let me provide a
couple of short quotes from a document I found in my library review:
Report No. ORB-2-3, "Measurement of Factors Affecting Jungle Radio
Communications", by the Operational Research Branch, Plans and Operations
Division, Office of the Chief Signal Officer, Room 3 D 320,  The
Pentagon, Washington, D. C.,  Dated Nov. 10, 1943.  (The report was
declassified on 15 April, 1946).

"Equipment Performance and Range Predictions":
Page 13:  "When using MF or HF equipment, such as the SCR 694, for
communication of more than 1 mile through heavy jungle, sky wave
transmission MUST BE employed (emphasis added).  This involves sending
the radio energy almost vertically upward and having it reflected back
down to the receiving location from the ionosphere."

"Conclusions":
Page 14:  "C.   Ranges greater than 1 mile with MF or HF sets require use
of sky wave transmission.  This involves the use of antennas radiating
energy almost vertically and the employment of ionosphere predictions for
optimum results."

It seems by 1965, the Army must have forgotten, so maybe it should be
"rediscovery" of NVIS.  And they had sent a team (size unrecorded) to
Panama for several months in 1943 to make extensive measurements in the
jungle at frequencies from 2 Mc. to 100 Mc., and then summarized the
data, drew conclusions, and published the data and recommendations in
late 1943.  The report includes a 15 page appendix from a 1943 Jansky and
Bailey report on "Radiotelephone Communication Between Mobile Units" with
extensive equations and graphs for calculating radio performance (outside
a jungle).  The initial distribution list for this document runs to over
200 copies, so that was a lot of forgetting.

"Nothing new under the sun."

73,
George
W5VPQ

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