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fv1609

Mystery Object No.124

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Of course there would be no pictures like this on the real machine, but this drawing illustrates the appearance of some targets & their behaviour. The double lines are moved over the particular trace to get an accurate range reading.

 

I am not clear how the spacing of the display relates to object size & speed. But I suspect the slow moving soldier, has bigger blips than the faster Rover or even a tree blown in the wind. I suppose an enemy unit would be best advised to congregate around wind swept trees to minimise detection, before the final assault?

 

I think it would require considerable operator skill & experience to untangle what is going on by just staring at these lines. With many targets of different types the screen could become quite chaotic. But I suppose the idea is to alert a unit that something untoward is soon to come upon them.

 

App1537.jpg

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Yes! Any ideas what the mechanism might be?

 

None at all, and not sure if I do now even after reading your explanations..

 

I just tried a rather catch all answer, everybody else did the work..

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None at all, and not sure if I do now even after reading your explanations..

 

I just tried a rather catch all answer, everybody else did the work..

 

A good technique! Often I've noticed people put a lot of work ferreting through details & easily ending up getting bogged down in the detail of a blind avenue, yet someone more detached has an overview of things & comes in with a googly & gets it!

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I actually guessed this right first time, just joined in too late to play ;) (dayjob has involved designing radar countermeasures)

 

My guess is that the x-axis represents time and the antenna array is pretty highly directional. That would explain why the trace is broken with a much higher frequency for the vehicle than the man - it's measuring the frequency of motion so you're actually seeing the man's footsteps. You would swing the antenna array to look in different directions and the display would let you know about movement at different ranges. The range indicator double-lines work in a similar way to the range gate on a normal radar system - in this case they have a constant signal so it always shows up, and you can choose the frequency of oscillation so you would know what range it represented (and so what the range of the track you overlaid was at).

 

The current Blighter radar actually works in a pretty similar way - the difference is that the beam is electronically scanned in both azimuth (by beam-scanning) and range (by altering the radar frequency). The operator display shows a wide field of view with a semicircular display on it and movement shows up as a range/azimuth 'cell' lighting up. You can then listen to the Doppler signature as an audio signal and can actually tell the difference between something walking on four legs (sheep) or two (sniper). Clever.

 

Do I win a secondary prize? :D

 

Stone

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Very useful to know when trees are attacking you,
Perhaps Macbeth should have had such a device at Dunsinane Castle? While encamped in Birnam Wood, the soldiers were ordered to cut down and carry tree limbs to camouflage their numbers, thus fulfilling the Witches' third prophecy. (I'm not educated it was the book I had to study for 'O' Level)

 

 

can it spot Triffids as well?
Would have thought so!

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You can then listen to the Doppler signature as an audio signal and can actually tell the difference between something walking on four legs (sheep) or two (sniper). Clever.

 

This is all music to my ears. I remember doing this on 10Gc/s (before Herr Hertz got into units) In 1972, this was before Gunn devices got into the public domain I bent the cavities of klystrons like KS9/20 up into the amateur band that was then 10G to 10.5G. I built a duplex rig with a seperate TX & RX dish with a 30M IF.

 

A novelty was aiming the contraption at the traffic low & just feeding the detector head into an audio amp. It was quite good fun trying to guess the vehicle size & speed by the woosh & wees from the amp. It certainly had a sobering effect on spped merchants!

 

 

Do I win a secondary prize? :D

Stone

Third prize actually, I think second goes to Lee & Neil :-D

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This is all music to my ears. I remember doing this on 10Gc/s (before Herr Hertz got into units) In 1972, this was before Gunn devices got into the public domain I bent the cavities of klystrons like KS9/20 up into the amateur band that was then 10G to 10.5G. I built a duplex rig with a seperate TX & RX dish with a 30M IF.

 

A novelty was aiming the contraption at the traffic low & just feeding the detector head into an audio amp. It was quite good fun trying to guess the vehicle size & speed by the woosh & wees from the amp. It certainly had a sobering effect on spped merchants!

Yep, do that with an e-scan head at 16?GHz with some fancy user interface stuff and you've got a Blighter, pretty much :)

 

Stone

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something to do with painting the white lines on the road, measuring how far one has to walk with the paintbrush, and then how much further one needs to go, til one needs to change to a different line configuration, ie double yellow, single whitee line with broken lines etc....

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ZB298 (aka Zebedee) or Radar, GS No.14 ??

 

Yes it is indeed, spot on, well done.

 

App1538.jpg

 

App1540.jpg

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