[Laser] Initial 650 nm tests

[Leigh Rainbird]

Built my AM 650nm transceiver today.

Have been mucking around with the acutal laser module and haveing a
bit of trouble focusing the beam. Its a pointer I modified.

I have some bicycle reflectors nailed to the trees down the front
paddock, around 0.8 Km away. I aimed the beam at the reflectors and
could see it coming back.

I went down the front with the RX section and tried to see if I could
hear audio coming through, but the beam was not focused enough at
that distance.

Tried a slight refocus and went back down the front, but when I got
there the beam moved to high and I could not access it.

Moved the beam closer to ground and drove down there again and found
it on the ground. I came back to about 0.7 Km and tried to see if I
could copy any audio. The beam was not to bad at that distance this
time, probably about 1/2 meter diameter. No copy initially then I
realised the RX antenna was not in the beam fully, after I got fairly
well in the center I could hear audio out the speaker!! wow!

Q5 copy of a playback of the VK6 openings from last year, amazing to
copy audio from a laser beam of light. I was using only the small
photo-diode.

Well, i've set the mark and now I'll have to try and better the
distance. Will be interesting to see how far we can go.

Regards

Leigh VK2KRR

PS- This is an Oatley Electronics kit