[Hidden-tech] WiredWest fiberoptic broadband

[Reva Reck]

Just anecdotal, but what we've found in Warwick with 900Mhz is that 
sometimes we get a strong signal where we don't expect one (trees in the 
way) and sometimes we have an almost clear line of sight and don't get a 
good signal. It's been really weird. We had one installation where the 
signal got worse after all the leaves were off the trees. One of our 
installers speculated that a nearby pond, frozen in winter, was bouncing 
signals that were interfering. It did help improve the overall 
reliability of the network to throttle down all the subscriber radios.
    You may understand all this in engineering terms, Jim, but from my 
point of view, it's all magic. We might as well say an incantation 
before each new installation! Then again, I'm not (fortunately) 
installing these things.

/Reva Reck/

/reva//@//revareck.com/



ussailis at shaysnet.com wrote:
> Absorption by leaves is what is reported by several sources.  The issue is
> how this is measured. Typically an experiment is set up where a source
> (transmitter and antenna) sends energy thru the forest, and the energy on
> the other side is measured with a receiver and antenna.
>
> Unfortunately this measurement does not measure the energy reflected by the
> leaves, which is typically back-scattered. And, by conversation of energy,
> what doesn't go into the forest isn't measured on the other side.
>
> I made several observations of this and came to the conclusion that at 700
> MHz and 2900 MHz that back-scatter was dominant, which explained the
> multipath that I measured.
>
> Since my last email, a client found ad for a gadget in the WiFi band that
> claimed to have built-in multipath reduction. It claimed to use
> 'post-priori' processing information.
>
> There was no accompanying patent number, so I remain a skeptic. 
>
> Yes, propagation gets more directional as frequency goes up. There is some
> 'bending' around sharp edges, but the sharpness of the edge is inversely
> related to frequency, so for our purposes, as we say "RF don't go thru
> rock."
>
> BTW, this is the drive to go from the 2.45 GHz band to 700 MHz. The other
> drive ad nothing to do with technology...The FCC netted 19.8 B$ from the
> "sale" of the frequencies that were freed-up from the move to digital TV.
> Guess who eventually pays for that? 
>
> And the bandwidth of fiber is the bandwidth of light. Astronomically more
> than what can be achieved even with millimeter transmission. The tradeoff
> is between lots of "wiring" vs some wiring plus towers and access points.
> Politically I think fiber wins here.
>
> Cost-wise? I am not so sure.
>
>
> Jim Ussailis
> jim at nationalwireless.com
>
>
>
> Original Message:
> -----------------
> From: Robert Heller heller at deepsoft.com
> Date: Sat, 17 Apr 2010 13:39:03 -0400
> To: ussailis at shaysnet.com, reva at revareck.com,
> hidden-discuss at mm01.tnrnet.com, heller at deepsoft.com
> Subject: Re: [Hidden-tech] WiredWest fiberoptic broadband
>
>
> At Fri, 16 Apr 2010 22:49:23 -0400 ussailis at shaysnet.com wrote:
>
>   
>>    ** Be sure to fill out the survey/skills inventory in the member's
>>     
> area.
>   
>>    ** If you did, we all thank you.
>>
>>
>> The issue with trees, etc is known as "multipath." It represents signals
>> arriving from many directions into your antenna. The many directions are
>> caused by reflections from leaves, trees, hills, etc.
>>     
>
> I also understand that the leaves also tend to absorb the higher
> frequencies, esp. those edging up into microwaves.  That is, some of the
> radio signal is being turned into sugars (not a lot or particularly
> efficiently). 
>
>   
>> Multipath gets worse as frequency increases. 
>>
>> Everyone who drives and listens to an FM radio has experienced it: You are
>> listing to a interesting program say you stop at a light. The signal is
>> distorted, & garbled. That is a multipath null (where the sum of the
>> various signal directions results in a very reduced, or null, signal
>> level). You inch forward a wee, the signal & interesting program is back.
>> You moved out from the multipath null.
>>     
>
> Of course, the FM broadcast band is between 88 and 108mhz and broadcast
> FM transmitters are far more powerful (in the kilowatt and 10s of
> kilowatt range) then any sort of digital wireless transmitters (which
> are about 1/4 watt). The long-distance wireless are 700mhz and 900mhz. 
> WiFi (802.11) is in the 2.4Ghz band.  The higher the freq., the worse
> the foliage affects it (absorption / reflection, plus the more
> line-of-sight the signal needs to be (this is where the hills come in).
>  
>
>   
>> One problem with wireless broadband is the antennas are fixed, while the
>> mutipath null moves about because the trees, etc move about. This results
>> in the null moving about. Since you can't easily move the antenna, you
>> can't control it.
>>
>> Wireless broadband in the clear works well. Thru the trees doesn't work so
>> well. Thru rocks (ie hills) it doesn't work at all. 
>>     
>
> One should also note: it won't work well though a "shielded box".  Some
> building walls behave like a "shielded box" (metal studs or rebar).  Of
> course concrete is mostly rock...
>
>   
>> This is another problem we face here in W.MA. Many "access points" would
>>     
> be
>   
>> required to service few customers because of the hills. Each of these
>> access points would require a transmitter / receiver and antenna on a
>> tower. Some folks don't like that because they think (wrongly) that it
>> lowers their property value. This is the NIMBY aspect of it all. In some
>> ways the politics are more difficult to overcome than the engineering. 
>>
>>     
>
> In some places, politics aside, the number of "access points" would be
> so high, that it might be cheaper to just run fiber optic.
>
> Another very important point is that ANY wireless technology is doomed
> to becoming obsolescent fairly quickly -- the equipment is very
> specialized (as to frequency and signaling methods) and any improvement
> in the technology would require wholesale replacement.  Fiber optic, is
> pretty much 'future proofed': the bare fiber optic has more bandwidth
> capability than the *electronics* currently available to drive it.  As
> the technology advances, all that needs to be updated/replaced are the
> interface points -- the fiber (on the poles or buried in the ground)
> would still be usable as is.
>
> One other thing: wireless technology is bandwidth limited.  
>
>   
>> Jim Ussailis
>>
>> jim at nationalwireless.com
>>
>>
>>
>>
>> Original Message:
>> -----------------
>> From: Reva Reck reva at revareck.com
>> Date: Wed, 14 Apr 2010 12:17:24 -0400
>> To: Hidden-discuss at lists.hidden-tech.net
>> Subject: Re: [Hidden-tech] WiredWest fiberoptic broadband
>>
>>
>>    ** Be sure to fill out the survey/skills inventory in the member's
>>     
> area.
>   
>>    ** If you did, we all thank you.
>>
>>
>>
>>
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