Private free-space communication.

coderman coderman at
Wed Jul 7 13:29:53 PDT 2021

Hash: SHA512

‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐

On Wednesday, June 23rd, 2021 at 3:41 AM, grarpamp <grarpamp at> wrote:

> On 6/23/21, Steven Schear schear.steve at wrote:
> > The problem with IR laser comms is its only p2p, LoS
> Cheap, works. Use whatever works.
> But for moving bandwidth, digging or stringing fiber and copper,
> or mounting laser... seems hard to beat on cost X speed basis.
> Maybe source simple IR laser module kit from China if it's still
> too high at retail due to fancy targeted-to-business-user
> remarketing bullshit...
> Aren't [the rest of] free space optics solutions still big $$$? ...

the big expense with FSO is compensating gimbal stabilizers for
alignment - all the commercial offerings seem to consider this a

as you say, cheap works - and you might be able to compensate manually
with modern electronics.

i still love the idea of FSO links in a p2p mesh network.
AODV with multi-radio (FSO among wireless in this case) benefits
from asymmetric links and capacities.

> Is this UV / freespace tech at consumer production and price level, links?

would be great to see a crowd funded effort!

the pureLiFi device looks interesting, but proprietary :/
[ ]

there are some research works on FSO for VR headsets, and such an open source
effort might be adapted to long range.

here's an interesting system using fiber optics on each end to
achieve higher throughput:

“In urban [settings], due to the influence of factories, automobile exhaust, and other factors, there are more particles, molecules, dust, and so on in the atmospheric channel than in other places, such as mountains,” said Zhan. “These factors lead to serious attenuation of optical signals, resulting in very low received power.”

The group used standard single-mode optical fibers on the transmitter side of the system to launch 16 ultrahigh-definition video streams as free-space optical signals. The key upgrade they made to the system for it to work was at the receiver, where they used an OM4 multimode fiber rather than single-mode fiber, resulting in a 10-decibel improvement to the signal coupling efficiency.

Video transmission with few errors was demonstrated in different parts of the day, different seasons, and different weather conditions.

The test range was limited to 2.1 kilometers because of obstructions in the high-density urban setting. From the high power margin in the 2.1 km link demonstration, the researchers expect to be able to easily extend this distance.
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i am having trouble finding more detail on this system,



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