On 19/05/10 11:09, (Ted Harding) wrote:
Sorry to be completely off-topic, but there's quite a few of you who are savvy in rare areas; plus, you're local!
Scenario: At times during the last few days I've seen a low-slung white car/van driving around. It has "Anglian WILLHIRE" on the sides. On the roof is mounted a blackish flat plate, about 15in x 9in in size and angled so that it is elevated about 45deg above the horizontal and facing forward. Perpendicular to this plate (therefore pointing upwards at about 45deg to the vertical) is an array of rods, which seem to be about 3in long and about 1/2in (or a bit smaller) in diameter. I couldn't count exactly, but I'd say it looks like a 4x6 array. (All quantities in this description are approximate!)
The only thing I can think is it is some sort of radio survey vehicle and the plate you saw is some kind of bizarre spatial diversity antenna array.
Maybe it is testing mobile network signal strength (3 inch antennas wouldn't be a million miles out from a 1/2 Wave antenna at around 1800mhz) or maybe it is trying to isolate a source of interference/illegal broadcast.
That said I don't understand the 45° inclination this being the case and the plate sounds too small to be truly useful for path finding as I'd expect spatial diversity to require the "rods" to be at least a wavelength apart. So then we are looking at the rods being full wave antennas and therefore it puts us in to the realms of WiMAX and some emergency services.
Any chance of snapping a picture if you see it again ?