Aerial photography - Ancient Gallery

These three very interesting pictures were sent in by Gareth Foster of London. Thanks Gareth! Any chance of any more, mate? Here’s Gareth’s very illuminating accompanying note:

Hi Bill,

Thought you might be interested in the attached photos.

The first one shows a Band I halo and Band III array. The Band I halo was never a common aerial but this excellent specimen in Greenwich is pointing at the old Alexandra Palace transmitter so it must have been there a while.

At first it looks like a loop but in fact the two ends of the halo are tied together with insulating material. Note also the matching stub across one of the elements. The Band III array is pointing at Croydon.

The second is something I've not seen before. It appears to be a UHF quad with quad reflector. There is a dipole with loading coils in the middle for Band I, the coils also acting as RF chokes at Band III so that the inner portion of the dipole is tuned to Band III. At least that's how I think it works. I remember indoor aerials on this principle. The thick lead coming away from it is in fact twin ‘shotgun’ coax so there are separate downleads for UHF and VHF.

The third photo shows the aerial I inherited when I moved to my present house 18 months ago. The X reflector is pretty strange. I think it is quite old and I've seen a number of similar examples in this area of SE London. It has line of site of Crystal Palace and the signal from it is 25dBmV on Ch23 (ITV) rising to 35dBmV on Ch 33 (BBC2), then falling back to 25dBmV on Ch 37 (CH 5). No wonder I got blocking on my Freeview box when I moved in! I've now routed it to an 8 way passive splitter in the loft via a 3dB pad and 3 of the outlets are routed to rooms in the house, the other 5 terminated for possible future use. I wonder if this might be an original single channel aerial from UHF BBC 2 only days. This could explain its rising gain through the Group A channels.

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