On 9/8/2010 10:50 PM, Richard Clark wrote:
On Wed, 08 Sep 2010 21:35:19 -0700, Roy
wrote:

so either my (and Frank's) calculations are grossly incorrect
or SPAWAR thinks there's a market for such inefficient antennas.

The point I caught, and apparently was not modeled, was the discussion
of antenna height for any particular band. Albeit, such mention was
fleeting, but it sounded suspiciously like half wave, not quarter wave
dimensions.

Aside from that speculation, power specs for military usage are
appropriate for theater operations, not global communications. When I
taught UHF/VHF in the Navy, 10% efficiency was considered perfectly
acceptable as point-to-point communications was the only expectation
and that was rarely as much as 20 miles at best. Experience teaches
that even that only takes 100s of milliwatts.

73's
Richard Clark, KB7QHC

That's still an order of magnitude better than what this antenna seems
able to do at VHF, although the demonstration clearly showed it to be
adequate for working a local repeater with an HT.

But what about HF, which the video clearly mentions? Is a fraction of a
percent efficiency adequate for typical communication needs? I know that
some military HF use is NVIS, for which a vertical antenna is poorly
suited to begin with, so that probably wouldn't be an application. Are
milliwatts of radiated HF used and useful for theater communications?

Roy Lewallen, W7EL