Monkey Brains

Well it is an inherently local system so the techs must be close by.

Reply to
Tom Del Rosso
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No, it is "beam steering". There is an array of small antennas at the feed position and the radio selects the best combination of them, shifting the focus position and thus the direction of the beam. There are leds on the case that indicate if the selected beam is off-center and the dish can be initially aligned using those. The current offset angle can also be read from the web interface.

Of course this is not a professional system. It just shows what can be done today at an incredible price point.

Reply to
Rob

Not really. Especially if like in the case of John's company a very narrow RF beam is used.

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Regards, Joerg 

http://www.analogconsultants.com/
Reply to
Joerg

An interesting property of the 60 GHz wavelength is that it is absorbed by the oxygen in the atmosphere, so even when you put the antennas at high locations the signal will not get further than about a mile. Combined with the narrow beamwidth of the antennas, this means that the frequency can be re-used many times (so indeed, small cells).

Reply to
Rob

I started to ask if phased arrays could be viable in a mesh network but realized it would be too inefficient.

If a phased array only adjusts a few degrees (going into a parabolic reflector) then I guess it would be more efficient than some 120 degree RADAR or something. Radio stations use 3-element arrays but that's just to get most of the power going one way, while they actually want some to go the other way.

By measuring the AGC voltage on the dishes I used to set up, I could get them within a small fraction of a degree but I couldn't say how small. Beam steering could have better resolution but depends how well they're made.

Reply to
Tom Del Rosso

How odd; from here I can see eight networks that advertise, and there may be some silent ones, too. If my home is any example, there's a smartphone, tablet, Chumby, two blue-ray players, TiVO, Roku, and videocam that connect at various times...dozens of talkers between those networks.

Not anachronisms as long as they make money. Cable systems are currently losing customers to broadcast.

The charm of 'open vast spectrums' is lost on me; I'd want a bit of broadcast spectrum for voice/data/video (DTV and FM suffice), and a parallel point-to-point scheme that doesn't slosh data to any and all neighbors. If net neutrality were as strong a protection as postal regulations, I'd be happy with a TCP/IP fast channel.

OK, I'm enough of a nerd to also want AM broadcast, if only because crystal radios are SO cool. Shortwave optional.

Reply to
whit3rd

This was a 89cm dish - 36", with a J mount and two stay bars. It's held down with high tensile roofing screws, not cruddy mild steel lag bolts.

Apart from that being impossible - the center of mass is located in a void. I'm sure I could get different figures depending on the size of the mallet chosen... what's this going to demonstrate?

with 2g acceleration the mounting needs only to withstand three times the normal weight of the dish. and the bolts are all at-least torqued five times harder than needed to hold the dish on target during adjustment.

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Reply to
Jasen Betts

There is another model of the same device (without the dish) that uses the phased array to steer the beam over a wide angle like a phased array radar. These can work in a point-to-multipoint setup over a shorter range (like 200m).

And also the software. They have been improving the performance of the thing just by upgrading the software that runs the beamforming.

Reply to
Rob

Or the trees grow leaves (I believe a problem at 28GHz).

Those affect the link budget, and can naively be taken into account. However, the interactions between tx power, link budget, co-channel interference, adjacent channel interference, topography are, ahem, "interesting".

In practice there is an awful lot of suck-it-and-see.

Even in mature networks there are "problem cells" where the network operations staff don't understand what's wrong and, sometimes they don't even know what's "out there". Even if they have adequate inventory control/discovery, their staff will go out and tweak an antenna until the (current) problem goes away - and not bother to inform the network centre.

Reply to
Tom Gardner

Back in the early '80s I helped design the first civilian direct-broadcast satellite system, SpaceTel from AEL Microtel in Vancouver BC. (Actually it was in Burnaby, but nobody knows where that is, and it's right next door.)

It was a 12/14 GHz system that fit in a single rack and would give you a few Toronto/Vancouver/Riyadh/Johannesburg dial tones from some remote place in the bush--pretty swoopy for 1982. It was good for mining camps, oil rigs, and so on, and was quite happy operating in a tin shack in the Arctic or the Saudi desert. I recall that there was a heat pipe someplace in it that was designed to freeze up in cold weather to reduce the total temperature range.

It used 3-foot dish antennas, which we aligned using a cardboard set square cut for the appropriate elevation angle for the installation's latitude, a compass for azimuth, and a well-calibrated boot for fine adjustment. (Of course we also dragged along a Tek 7S12 spectrum analyzer for percussive peaking.)

Cheers

Phil Hobbs

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Dr Philip C D Hobbs 
Principal Consultant 
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Reply to
Phil Hobbs

Back in about 1985 I lived in San Mateo for a semester, and one night we had the most amazing sequence of thunderstorms I have ever seen. (I've been in NY for over 30 years now, and we get some doozies, but never anything like that one.) Mo and I stayed up most of the night watching it from our 6th floor balcony.

Cheers

Phil Hobbs

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Dr Philip C D Hobbs 
Principal Consultant 
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Reply to
Phil Hobbs

Attaching a little something to everything I own, so Google could make sure I brush my teeth for 5 minutes every time. Comforting.

Cheers

Phil Hobbs

(Who isn't going to have any stinking IoT in his house till the good old stuff disappears off eBay)

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Dr Philip C D Hobbs 
Principal Consultant 
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Reply to
Phil Hobbs

This is seriously embarrassing. Most of what I wrote above is wrong.

In 1989 we did not have Wi-Fi and DBS satellites. The antennas that I was running around realigning in 1989 were 460 and 900MHz yagis and no dishes. All of what I wrote above actually happened and are not fabrications, but occurred over about a 15 year period and not in

1989.

What happened was that my sense of time failed. It was as if everything over about a 15 year period happened at one time, in this case in 1989. I've had this problem erratically for much of my life. At the time when I write something like the above, I cannot tell that my sense of time is distorted. However, I can usually tell by simply waiting about 30 mins and double checking what I wrote or said. This time, I was in a hurry and didn't wait. A recent change in my heart meds might have also been involved.

I'm not sure what to do next. Of course, I just sent email to the doctor asking if I can change back to the previous meds. I'll probably take a break from posting on Usenet and various mailing lists until I'm sure there will not be a repeat performance. This is all rather painful. Having trashed my own reputation, the best I can offer is this apology and explanation.

My apologies (again).

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Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
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Reply to
Jeff Liebermann

An installation is always preceded by a survey. No trees would be near the path.

Reply to
Tom Del Rosso

This business is so complex that it's hard to remember what happened when. After my first hundred designs, I could remember every schematic. After the first thousand PCB designs, one starts to forget details. That's why we write stuff down.

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John Larkin         Highland Technology, Inc 
picosecond timing   precision measurement  
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Reply to
John Larkin

I think your reputation is more resilient than that. No one bought or sold stock based on your post. The pain is all yours, and is part of the pain of aging, so there should be no embarrassment or guilt to go with that pain.

Reply to
Tom Del Rosso

Our old house was built in 1892, and the chimney was brick with, probably, beach-sand mortar. You could scrape the mortar out with a fingernail. In '89, the chimney sort of crumbled but didn't go through the roof. I took it down a brick at a time and turned it into a skylight.

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John Larkin         Highland Technology, Inc 

lunatic fringe electronics
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Reply to
John Larkin

Our new energy-efficient lighting system at work is infuriating. The switches are complex and erratic, motion-sensor lights go off when they feel like it, lights go on when you walk into a room whether you want them or not. I figured I'd replace a smart switch with a dumb one so pulled off the cover plate. The switch has an RJ45 and CAT5 up the conduit. So I'll have to pull AC wires, too.

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John Larkin         Highland Technology, Inc 

lunatic fringe electronics
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Reply to
John Larkin

That happens in Truckee; on a big holiday weekend, a zillion kids are watching movies when they should be out hiking in fresh air, and things slow down. But that's probably a data pipe limitation into the whole town, not a local wi-fi issue. There are only a few houses in our wi-fi radius.

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John Larkin         Highland Technology, Inc 

lunatic fringe electronics
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Reply to
John Larkin

But many cable customers are only buying internet service and not paying for "channels." Watching a show at some specific time is so last millenium.

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John Larkin         Highland Technology, Inc 

lunatic fringe electronics
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Reply to
John Larkin

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