[Laser] test

[Steve J. Noll]

Even NASA with their facilities didn't get a return from every laser 
shot to the retroreflector on the moon.
My best 2-way was 57.7 miles, 2.5 mW HeNe  & photomultipliers and it was 
easy. PMTs were probably not necessary. Never tried a longer distance.
I suspect any distance (short of the moon) is possible with reasonable 
equipment (not needing a lock-in amplifier, etc.,) as long as the two 
points are line-of-sight from each other.

73, Steve WA6EJO


On 8/1/2016 7:55 PM, Raymond Cote wrote:
> What kind of distance and at what power?
> Are you talking of bouncing a las off the moon reflector?
>
> Women and cats will do as they please, and men and dogs should just relax and get use to the idea.
>
> -Robert Heinlein
>
>> On Aug 1, 2016, at 16:20, Steve J. Noll <sjnoll at ix.netcom.com> wrote:
>>
>> Silicon photodiodes match visible and near infrared lasers & LEDs well, are fast, and have reasonably large active areas.
>> Solar cell - essentially a silicon photodiode, but optimized for power generation, not small signal detection, slower, probably noisier, no gain, large area, good wavelength match.
>> Phototransistors also match said wavelengths well, have some gain, but are slower and have tiny active areas which are harder to get all of your light into.
>> Photoresistors are very slow responding, no gain, large areas, not bad wavelength-wise, but again, very slow response time.
>> Silicon avalanche photodiodes extremely fast, have gain, but take high voltage, expensive.
>> Photomultiplier tubes - if you're trying to set some extreme distance record. Take high voltage, very large sensitive area, tremendous gain, very fast, usually not great spectral match but gain makes up for it.
>>
>> 73, Steve WA6EJO
>>
>>
>>> On 8/1/2016 1:52 PM, Zack Widup wrote:
>>> I've been wanting to play around with laser comms for quite a long time. I
>>> have various solid-state lasers and I have some lenses. I think I saw some
>>> recommendations on what to use for detectors once but I can't find that
>>> info now. What are best used for detectors?
>>>
>>> 73, Zack W9SZ
>>>