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Standard User eckiedoo
(member) Sun 17-Feb-13 07:27:48
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Re: Why do some FTTC cabinets have TV aerials beside them?


[re: gazzyk1ns] [link to this post]
 
I agree that most WiFi applications are based on omni-directional (convoluted) aerials/antennae, but Directional WiFi aerials are available as shown here-

http://www.wifi-shop24.com/en/WiFi-Antennas?gclid=CK...

There was a recent thread on this forum about getting WiFi to a garden shed, obstructed by a thick line of conifer trees, two of those directional aerials may have produced a solution.

I am aware of co=linear arrays of dipoles, in excess of 100, operating in the 10 GHz / 3 cm band, producing extremely narrow beams.
Standard User yarwell
(sensei) Sun 17-Feb-13 14:32:31
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Re: Why do some FTTC cabinets have TV aerials beside them?


[re: haggismn] [link to this post]
 
most likely water company infrastructure - sewage pumping etc.

--

Phil

MaxDSL - goes as fast as it can and doesn't read the line checker first.

MaxDSL diagnostics
Standard User eckiedoo
(member) Sun 17-Feb-13 15:04:49
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Re: Why do some FTTC cabinets have TV aerials beside them?


[re: haggismn] [link to this post]
 
Another possibility is that it is for a local Cable TV system; and that the cabinets may have been there for some years.

With the change-over to Digital Terrestial TV, a more directional but broad (TV) band aerial is required to cover the range from about 400 MHz to 800 Mhz, so has become obvious with a newish pole/standard; and a more sensitive (longer) aerial at the top.

I understand that there were/are quite a few in the Valleys area, in-filling "shadow" areas.

====================

A465 Head of the Valleys road, as originally built - rather like doing "circuits and bumps" in a small plane.

Take off from one roundabout, climb up to the summit, then dive down to land at the next roundabout, "taxi" through it to take off again ... .


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Standard User gazzyk1ns
(committed) Mon 18-Feb-13 01:49:02
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Re: Why do some FTTC cabinets have TV aerials beside them?


[re: eckiedoo] [link to this post]
 
In reply to a post by eckiedoo:
I agree that most WiFi applications are based on omni-directional (convoluted) aerials/antennae, but Directional WiFi aerials are available as shown here-

http://www.wifi-shop24.com/en/WiFi-Antennas?gclid=CK...

There was a recent thread on this forum about getting WiFi to a garden shed, obstructed by a thick line of conifer trees, two of those directional aerials may have produced a solution.

I am aware of co=linear arrays of dipoles, in excess of 100, operating in the 10 GHz / 3 cm band, producing extremely narrow beams.


Interesting, I stand corrected.

They would never use a Yagi aerial (wideband or not) for wi-fi though, would they?

Edited by gazzyk1ns (Mon 18-Feb-13 01:52:47)

Standard User eckiedoo
(member) Mon 18-Feb-13 07:35:44
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Re: Why do some FTTC cabinets have TV aerials beside them?


[re: gazzyk1ns] [link to this post]
 
Agreed that a Yagi aerial would be unlikely for WiFi, difficult to produce the physical parts and assemble them etc.

There is a fair chance though that a slot aerial design might be considered, and the convoluted "bent piece of metal" found inside Modem/Routers etc may reflect this-

http://www.antenna-theory.com/antennas/aperture/slot...

With the Laptops & Netbooks I have seen opened up, the WiFi aerials seem to be built in to the hinges.

The 100+ dipole aerials I am aware of, were of extremely robust design, for various reasons.

Regarding WiFi and its Broadband aspects, you may find the involvement of Hedy Lamarr (Hollywood Film/Movie Star 1940s) of interest, as WiFi uses similar Frequency-Hopping techniques-

http://en.wikipedia.org/wiki/Hedy_Lamarr
Standard User yarwell
(sensei) Mon 18-Feb-13 09:32:22
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Re: Why do some FTTC cabinets have TV aerials beside them?


[re: gazzyk1ns] [link to this post]
 
They would never use a Yagi aerial (wideband or not) for wi-fi though, would they?
yes, ideal for a client end pointing at an omni base station. Sometimes they live in a plastic tube so don't look like a yagi.

--

Phil

MaxDSL - goes as fast as it can and doesn't read the line checker first.

MaxDSL diagnostics
Standard User gazzyk1ns
(committed) Tue 19-Feb-13 06:21:52
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Re: Why do some FTTC cabinets have TV aerials beside them?


[re: yarwell] [link to this post]
 
But not on the scale we're talking about here, i.e. the photos. To be big enough to incorporate the reflector, that's a massive plastic tube which wouldn't fare too well once the wind got up a little bit. It would be so impractical to incorporate a Yagi aerial into a modern wi-fi receiver, unless we're talking about home-made solutions with whatever resources can be gathered.

I think the point is that this is clearly a water cabinet, and tens of thousands of water and electricity "stations" use a vertically aligned Yagi pointing at the nearest (usually mainly TV) transmitter. Relatively close to me, but a bit out in the country, there are at least two electricity poles with switchgear on them, which have the same Yagis - presumably to set an alarm off somewhere in the event of a failure, or if an engineer has unlocked the massive padlocked lever and thrown it.

None of this is anything to do with fibre, or related "wi-fi" as we principally know it, and that was my point. It has been interesting though, I assume the Yagis in tubes you're talking about are smaller than usual?
Standard User yarwell
(sensei) Tue 19-Feb-13 08:41:36
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Re: Why do some FTTC cabinets have TV aerials beside them?


[re: gazzyk1ns] [link to this post]
 
indeed the aerial pictured is not wifi frequency as its was too big and somewhere in the UHF area by the look of it.

Here's a wifi example

--

Phil

MaxDSL - goes as fast as it can and doesn't read the line checker first.

MaxDSL diagnostics
Standard User broadbandjockey
(member) Tue 19-Feb-13 09:27:41
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Re: Why do some FTTC cabinets have TV aerials beside them?


[re: gazzyk1ns] [link to this post]
 
In reply to a post by gazzyk1ns:
In reply to a post by simon194:
In reply to a post by Ribble:
May not even be a telco's cabinet . Have seen water companies use similar

It's most likely a water company remote monitoring setup.


Yes, a vertically aligned Yagi aerial is almost always water or electricity monitoring. In this case, from the fact that it's a small street cabinet, it would be water. The Yagi aerials will usually point to the nearest TV transmitter or relay, because that's where the water/electricity companies have sensibly placed their receivers.


That's right. In fact the utility companies use a part of the UHF band just below TV, about 410 MHz I think, the yagis you see will therefore have slightly longer elements, than the ones that are designed for TV reception, as well as being mechanically more roust than domestic models..
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