Monday 9 June 2014

Over The Horizon DX....On Lightwave

I was excited to read an article by Roger, G3XBM, in the June issue of Radcom magazine describing his experiments in non-line-of-sight (NLOS) lightwave work. Last fall, VE7CA, VE7BDQ and myself built LED lightwave stations, mainly due to Roger's inspirational blogs describing the development and progress of his own lightwave system. Our local work resulted in two exciting CW contacts between myself on Mayne Island and VE7CA in North Vancouver, about 54km away and on the other side of Georgia Strait. 

Our Lightwave QSO Path

The details of our system and contacts will be the subject of an upcoming article in 'TCA', the Radio Amateurs of Canada journal.

Although VE7BDQ did not build a transmitter, we did have one unsuccessful NLOS attempt, hoping to catch a signal from the bottom of a somewhat unstable cloud layer.

Roger's article describes the results of his low power 'clear air scattering' tests and levels of signal detection at varying distances. His success in this mode has given me renewed hope of eventually being able to cross the water via this method and maybe even doing it without the cloud layer!

Our systems used a 556 tone generator to produce a keyed 600Hz tone, but I think Roger's approach of using a crystal oscillator / divider as the tone source will likely produce a much more stable signal and one that would be easier to spot on a slow speed Argo or Spectran screen, as any attempts would be run in slow speed CW QRSS mode.

For more on Roger's excellent lightwave activities and NLOS experiments, visit G3XBM's Lightwave Blog pages that cover these topics.

If there are any others in the Vancouver lower mainland region who might be interested in joining in the lightwave fun, we would welcome your help....this is one activity where "the more, the merrier" is surely the case!

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