[Laser] New San Diego optical beacon

[Kerry Banke]

Art - Thanks for asking as your timing was perfect:)    Over 
the  weekend we installed a new 180 degree optical beacon which is a 
surplus  red FAA radio tower beacon we happened to obtain and made 
functional.  The original unit was a 360 degree beacon with about 300 
LEDs but we have split it in two as the location only needs to 
service 180 deg.  Right now the beacon draws 17 Volts at 4 amps and 
is producing a 450 Hz crystal controlled tone (50% duty cycle square 
wave). We made a screen capture and .wave file recording at 8 
miles  using my 4" optical receiver and Spectrum Lab. Spectrum lab 
shows the signal as about 50 dB above the noise in a 1 Hz BW.    I'll 
be happy to send it to anyone interested.  The scintillation was 
about 50% which is not bad compared to some previous attempts with a 
single high output LED beacon. Some of it I'm sure is the  time of 
year but also probably the fact that the beacon now is not quite such 
a point source. The LEDs are spread over a 12" high area which should 
help scintillation.  We're working on the next step which will 
probably  include adding MP3 player capability for a beacon message ( 
maybe PSK31,  Jason,  other?) and also a linear optical repeater.  Stay tuned.
  - Kerry N6IZW  with the Sand Diego Microwave Group -

At 02:46 PM 1/19/2007, you wrote:
>Hey Kerry, how 'bout an update on your LED dx activity there? I know 
>you did some 20 mile qso's with LED's.
>
>Any more new adventures?
>
>Art