Hi Miguel, From direct measurement, I know that the rule-of-thumb for a good-quality Fresnel lens is that it will produce a "blur circle" (e.g. "spot") that is...
Hi Miguel Following theory, the response is exactly the same because a photodiode is a photons to electrical carriers converter with a define ratio (quantum...
Thank you all for your response about how to focus into a photodiode. I remark this paragraph: As for lighting up a "portion" of the photodiode or "all of it",...
Hi Miguel, That is correct about masking the photodiode to improve performance by virtue of reducing beamwidth - and that's why I did it - but that's only true...
Hi Clint, Miguel and the group I thought i would point out that non-variable stars are one of the few "standard candles" out there with which to compare the...
You would need to take a lot of variables into account: Sky transparency, not the same on every place on earth. It also depends on star's elevation above...
Yes i agree, there are lots of variables. A better approach might be just a simple 1 through 6 scale (or 7,8 etc..) representing the magnitude of the faintest...
Hi, I am new to this group, so 'Hello World'. I'm not an 'optical comms' enthusiast, only a hobbyist. My interest in this stuff stems, ironically, from an...
Hello Bruce, Instead of using light have you considered using a different frequency? Inexpensive video transmitters of various frequency are available. You...
Hi Optical_DX group, We broke 100km barier. Last Friday Fritz OE1FFS and OK/OM3Kii operated by me succeed with 117km Laser contact. Some photoes and details...
Hi All, Seeing some talk about narrow optical filters recently, i wanted to bring up an old idea about using a glass prism to tune or pre-select the optical...
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Ron VK3AFW
vk3afw@...
Nov 20, 2011 10:24 am
Hi Tim, The idea is good but the diagram isn’t. If the prism is arranged to look like this Light in * ... * * Then the...
Thanks Ron, I wasn't sure how to draw the prism exactly, in fact it looks like it might either be a retroreflector as drawn or split the beam in half and make...
I would like to ask your help. Any suggestions would be greatly appreciated. I need to build a laser transmitter and transmit audio or video data using pulse...
Here's a good page on that but they are using AM and LED's: http://www.modulatedlight.org/optical_comms/LED_AM_video_link.html there are links to other sites...
Hi all I need some help to evaluate a strange effect I try today to bias direct way some PIN silicon phodiodes with a rather high current. Some large area...
... A photodiode makes a poor LED and also a LED makes a poor photodiode. Strange but true. I haven't played with this since the 80s, I wonder how much this...
Tank you for your point of view. New super bright LED are not so bad photodetector and some of them even give an avalanche gain effect if biased near the...
... From: "Dave" @tpg.com.au> To: "vk-vhf" Cc: Sent: Tue, 13 Mar 2012 22:04:56 +1100 Subject: [VK-VHF] International Conference on Infrared, Milimetre and ...
Hello, I am missing a bit of technical knowledge here so any advice is welcome! I have acquired a few laser diodes that are "B-mount" that is roughly a ...
