A nerdy moment.

As followers of this blog may realise, the Eye is a bit of a nerd.  We navigate by looking at satellite dishes (forgive a little geometrical inexactitude, but, as the ‘Sky’ satellite is at twenty eight degrees east, a quick glance at domestic satellite dishes gives a good idea of where south lies.  It’s so much easier than relying on the fact that moss grows on the north side of tree trunks.  Which isn’t true anyway).

Anyway, we digress.  We have a similar obsession with TV aerials.  As a young nerd, living moderately close to the Alexandra Palace transmitter,  we knew was that a knitting needle stuck in the TV set’s aerial socket worked well enough.  As an older nerd, living in Swansea, we discovered that English-speaking households pointed quite elaborate TV aerials across the Bristol Channel to pick up English broadcasts from Devon.  Welsh-speaking households pointed their aerials in a totally different direction, picking up the signal from a local transmitter.

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As an even older nerd, we look at tired aerial masts dropping off chimneys, with aerials pointing towards Australia, and we wonder what the reception is like.  Which was our initial reaction when we spotted this mast behind Camberley’s High Street recently.  It certainly is far from vertical.  But the odd thing is that the aerials mounted on it are roughly horizontal, so the mast is presumably meant to be at that unusual angle.  That’s a new one on us.

But we’re not awarding a prize to the first person to notice that this photo shows two aerials pointing one way, and three pointing in the opposite direction.  (None picking up Welsh TV, we suspect.)  It’s a little factoid that adds to our daily excitement……

Actually, we’re tempted to post a series of photos of town centre aerials.  A surprising number are obviously no longer in use.  Stay tuned!

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3 thoughts on “A nerdy moment.

  1. Good morning Eye.
    A a geek, you probably know that the technical name for a TV aerial such as this is actually a Yagi Antenna (or Yagi-Uda). Basically a high gain directional antenna which can be be used in a wide range of scenarios – most commonly for roof mounted TV aerials.

    The strange angled pole upon which the offending yagi is mounted suggests a different use – Active RFID. This is a system which uses powered tags attached to assets which get read by powerful readers. You will have been exposed to passive RFID in shops (the door alarms being passive RFID readers which are reading passive (unpowered) tags glued onto the goods). Active RFID is less common but is sometimes used to track amongst other things, trucks. Setting up effective read zones for active RFID can be a very precise (and sometimes Heath Robinson). The angle pole suggests that they want a read zone to detect when an asset is in a service area behind a shop, but they don’t want to get stray reads as a lorry passes along a road in front of the shop this would give a false “on-site” record. Despite the best efforts of attenuators (device that reduces the power of a signal without appreciably distorting its waveform) to tweak the read range, a physical movement of the mounting pole was deemed necessary.

    Alternatively, it may have just bent 🙂

    • Many thanks, Steve. You know much more than I.
      I guess that it’s possible to deduce the operating frequency from the aerial dimensions (not that it’s easy to work these out from the photo). Does RFID operate in much the same frequency band as UHF TV? Out of ignorance, I’d have guessed not. (I write as one who has a loft-mounted upteen element aerial dangling on a couple of lengths of string, feeding a masthead amplifier. It probably breaks all the rules of good practice – but it works… And the spiders love it!)

      • Nobody know more than the Eye! Especially about loft-mounted string dangling systems. Active RFID frequencies can vary but in the example I mentioned it would probably be 915mHz UHF. Anything that encourages spiders is a no-no for me!

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