[SMCARA] New HF Antenna

[tomnd3n at MD.METROCAST.NET]

Laser Com, Inc. of Titusville, Florida recently announced their
development of an HF antenna system based on their proprietary
laser communications system.

Dr. Benjamin Dover, Laser Com’s chief engineer, cited their research
into laser-based space communications as providing the “happy
accident” that led to the discovery of the laser based HF antenna
system.

Dr. Dover said that an accidental connection of the wrong cable
led to the discovery. A cable that had been carrying HF signals was
inadvertently connected to the modulation input of the laser transmitter
that that Ben was testing. “Imagine our surprise,” said Dr. Dover,
“when we noticed that HF radio frequencies were being radiated all
along the laser beam. This is something we never expected. The
possibilities are endless.”

Laser Com plans to market the HF laser antenna not only as a
commercial product, but also as a low cost amateur radio antenna.
Dr. Dover set up the prototype as a demonstration of the product’s
simplicity.

The secret to the HF laser antenna is in the base unit’s modulation
transformer that directly modulates the Plesseo-Dyminium laser crystal.
The user simply places the laser box on the ground and adjusts the
laser beam straight up into the air. As the laser beam rises into the 
sky,
the HF signal travels up the laser beam and is radiated all along the
length of the optical beam.

The laser beam shines nearly a mile into the atmosphere. However,
due to path losses along the beam, the actual HF radiation is only
transmitted by the first few hundred feet of the laser’s beam. The
result is an omni-directional vertical HF antenna that is several 
hundred
feet high.

Acting like a co-linear antenna array, the over all antenna gain is
approximately 10 to 15 dB, depending on the actual HF frequency band.

Dr. Dover said, “We are really excited about this product. There are no
antenna restrictions on an invisible light beam, no lightning risks, and
no damage from wind storms. The only down side is signal attenuation
due to heavy fog, which can attenuate the HF signal by as much as 6 dB.
Otherwise, this is as near to a perfect antenna as you can hope for.”

Laser Com plans to introduce the amateur version of this antenna at the
Dayton Hamvention this May.