Monkey Brains

I recall reading somewhere that in the distant past, in time known as the Sixties, the telco companies knew that consumers would eventually start demanding wider bandwidth channels than copper links could provide for, but fiber optics was still in its infancy and it was unknown to materials science if such a medium could actually support wide bandwidth communications.

So it seems they spent some time investigating the properties of relatively large-diameter spiral microwave waveguides that would be run under the streets to homes like water pipes, like an actual "tube" for the Internet

Once you've got one fibre laid, laying another is just blowing a new one down the existing pipe.

Australia's broad-band network initiative was designed to set up that infra-structure.

Granting that Australia's rural population density is very low, the remote outback gets served by satellite links (and that isn't happening all that fast) but the rest of the country (where most of the people actually live) isn't too bad.

I'm stuck with fibre to the building, but the building was designed with a telecommunications shaft, which accommodates all sort of links, including old cable TV coax.

--
Bill Sloman, Sydney

The uniform building code requires it and it's the owner's responsibility. Representatives from your insurance company will see you in court, and snicker, after the fire.

Not here.

Don't be silly.

--

John Larkin         Highland Technology, Inc 

lunatic fringe electronics

But we don't get lightning. The power lines do not have a high grounding wire like they have in most places.

We rarely see a little lightning far off in the clouds (like, maybe every few years) but no ground strikes.

--

John Larkin         Highland Technology, Inc 

lunatic fringe electronics

Bell also experimented with light in a pipe, focussed by temperature gradients.

--

John Larkin         Highland Technology, Inc 

lunatic fringe electronics

Requires lighting?

Up on the roof, with my mediocre eyesight, I counted 35 microwave dishes on nearby buildings. In the square mile or so around me, there were probably 20,000 cell phones and maybe a thousand wi-fi's. And that giant TV tower. And it all works.

--

John Larkin         Highland Technology, Inc 

lunatic fringe electronics

They are great. The data rates are symmetric and guaranteed minimum, not "up to" like most liars. If anything goes wrong, a tech shows up fast.

We're paying for 50+50, getting 6x that.

--

John Larkin         Highland Technology, Inc 

lunatic fringe electronics

The mast and cable grounds are not intended to protect your building from a direct hit. If that happens, the lightning will follow the network cable and eventually hit ground, leaving a path of destruction along its path to ground. What the ground does is offer a path to earth ground for current induced in the mast or cables by a nearby lightning hit. Such hits usually don't start a fire, but do tend to destroy equipment and zap people leaning against the tower or cables. The NEC doesn't care if you have a 100ft tower, or a 3ft tower. It needs to be grounded, as are all satellite dish antennas, CATV cables, and telephone MPOE boxes. Ask any electrician.

Probably more than you want to read, but the drawings should offer a clue as to what is involved: "Antenna System Bonding and Grounding Requirements in the USA"

I keep running into installations where the roofing company voids their roofing warranty if the owner or his contractors even walk on the roof. My office is in such a building.

How do you turn it off?

--
Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
Santa Cruz CA 95060 http://802.11junk.com 
Skype: JeffLiebermann     AE6KS    831-336-2558

What, never?

Sylvia.

I'd lose the searching device - how would I find that?

Sylvia.

The roofers included a footpath to make it easier to climb to the peak.

We also have a nice flat area where we'll have furniture and plants and a BBQ.

--

John Larkin         Highland Technology, Inc 

lunatic fringe electronics

Cell phone. Or an implant, so we could also find you.

--

John Larkin         Highland Technology, Inc 

lunatic fringe electronics

The FCC has a hard limit on maximum EIRP but raised it dramatically in

2013: The average equivalent isotropically radiated power (EIRP) limit is raised from 40 dBm (10 watts) to a maximum of 82 dBm (158,489 watts) depending on how high the antenna gain is. The peak power limit is 3 dB higher. The new power limit is comparable to others the FCC has in the fixed microwave services.This increase is expected to enable higher-capacity outdoor links extending to about one mile.

I would guess(tm) that you're thinking about the maximum power output that could be delivered by a smartphone style handset at 60GHz. Todays handsets typically deliver about 250 mW maximum RF output at 1.9GHz. Mine seem to spend their time running at about 50 mW output. I couldn't find anything on the efficiency of 60Ghz transmitters, but I think it's a fair assumption that it would be much less than todays smartphones. It's likely that the battery is going to limit the transmit power output to the low milliwatt range or less if it's a phased array crammed into a handset.

However, if you don't care about miniaturization, there's always TWT (traveling wave tubes) for V band that will deliver up to 200 watts with 30-60% efficiency: All that needs to be done figure out how to make it fit in a handset or Small Cell package.

--
Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
Santa Cruz CA 95060 http://802.11junk.com 
Skype: JeffLiebermann     AE6KS    831-336-2558

The latter might be a good idea in a few years.

Sylvia.

The limit I was referring to at 60GHz was simply that the transistors have to be small relative to the wavelength, and the consequent power density.

But that is from the memory of a conversation in 1996, and that conversation was of a report by the 60GHz transistor manufacturer. It was regarded as plausible by those with more direct knowledge than me.

FCC regulations were irrelevant at that stage; indeed they asked us to help set some!

Dedicated point-to-point systems are very different to ad-hoc cellular systems. They have different constraints.

The cell phones and wifi systems you mention are very definitely subject to capacity limitations.

Wi-fi has the advantage (and disadvantage) that walls windows and doors somewhat impede propagation, thus allowing (and enforcing) smaller cells. But in buildings propagation can be, um, surprising - leading to unpredictable high density spots and propagation holes.