David Platt wrote:

The same effect could result if you've got a buildup of dust or
tobacco-smoke tar on the laser diode or the photodiode. The more
light is blocked or scattered by these materials, the weaker the
detected signal.

Arfa and I have had a running discussion about this over the years on this
group.

I live 3,000 feet up in the desert, the air is dry and dusty. There is
plenty of wind all the time so there is no hydrocarbon buildup from
automobile exhaust.

The cleaning disks with the brushes work fine for me, I have never had
one scratch a lens, and they brush the dust off.

Arfa lives in England and has very different weather and the dust is more
of a sluge than dry dust. He always cleans his lenses differently.

(Arfa, want to chime in here?)

Geoff.



--
Geoffrey S. Mendelson, N3OWJ/4X1GM/KBUH7245/KBUW5379