FS UK: Tornado GR4 Ground Mapping Radar £75 + £40 UK shipping - Page 1
Forum section: electronics / general

author: voltsandjolts
author_rank: Unknown
timestamp: September 16, 2021, 01:53:30 pm
content: Cool ornament for the man cave?https://www.ebay.co.uk/itm/324345661214(not affiliated in any way, just noticed an unusual listing)

author: PlainName
author_rank: Super Contributor
timestamp: September 16, 2021, 03:42:39 pm
content: Interesting that it's classed as 'used'. Presumably they're hoping someone doesn't try it out on an actual Tornado and then claim it's not as described.

author: CJay
author_rank: Super Contributor
timestamp: September 16, 2021, 07:46:50 pm
content: Nice collection of RF bits in their catalogue, that radiation symbol on the GR4 RADAR worries me though

author: Gyro
author_rank: Super Contributor
timestamp: September 16, 2021, 07:58:36 pm
content: 4 available/5 soldP.S. You have to wonder what sort of person looks for a Eurofighter wing assembly on ebay!

author: Towger
author_rank: Super Contributor
timestamp: September 16, 2021, 08:05:04 pm
content: Her Majesty likes to put radiation stickers on all equipment which produces Ionising radiation.

author: babysitter
author_rank: Frequent Contributor
timestamp: September 16, 2021, 09:38:59 pm
content: Tubes with high anode voltage (say, big CRTs?) happen to spray X-rays.

author: Hydron
author_rank: Super Contributor
timestamp: September 16, 2021, 09:59:22 pm
content: If anyone is looking at the seller's other listings, then a heads up that you should take things described as "working" with a grain of salt if you don't want to be mucked around - I got a "working" probe from them last year that turned out to have a dead short in one end of the resistive coax lead.

author: CJay
author_rank: Super Contributor
timestamp: September 17, 2021, 06:40:54 am
content: Quote from: babysitter on September 16, 2021, 09:38:59 pmTube manufacturers involved in RADAR also like to use radioactive materials in their construction.As I say, those radiation warning stickers worry me.

author: voltsandjolts
author_rank: Unknown
timestamp: September 17, 2021, 09:34:46 am
content: Quote from: Gyro on September 16, 2021, 07:58:36 pmMaybe they're playing the long game, waiting to buy up enough parts to build a whole Eurofighter!

author: babysitter
author_rank: Frequent Contributor
timestamp: September 17, 2021, 11:31:14 am
content: Quote from: CJay on September 17, 2021, 06:40:54 amI'm aware of thoriated cathode to simplyfy emission (and radioactive Krypton in gas discharge devices for breakdown/ignition control), is there anything besides thyt to be expected?

author: firewalker
author_rank: Super Contributor
timestamp: September 17, 2021, 12:48:28 pm
content: A nice tear down for Mikeselectricstuff.Alexander.

author: radar_macgyver
author_rank: Frequent Contributor
timestamp: September 17, 2021, 03:24:47 pm
content: Receiver protectors often have either a Tritium tube or a point source of Promethium-147 to generate alpha particles as a keep-alive. When high-power RF enters the RP, the keep-alive provides a conductive path through which a plasma forms, and protects the receiver LNA from the RF.https://www.cpii.com/docs/related/4/RP%20Tech%20Art.pdfThat said, it looks like the sticker is on the TWT, so it could be due to X-ray emission. Sadly, the e-bay listing "Doesn't post to United States", else I would have bought one.

author: CJay
author_rank: Super Contributor
timestamp: September 17, 2021, 05:38:06 pm
content: Quote from: babysitter on September 17, 2021, 11:31:14 amThere's quite a history of radioactive sources in tubes, I know some recently manufactured parts contain 'unpleasantness' but I have no idea what's used in them nor what's inside that GR4 RADARSome historical info:https://physicsopenlab.org/2016/06/03/radioactive-electron-tubes/I appreciate those tubes are *ancient* but I've seen the ionising radiation warning signs on spares storage cupboards at active sites.If I bought that unit, I'd want something to hand that could verify it wasn't going to glow in the dark even when unpowered.

author: Gyro
author_rank: Super Contributor
timestamp: September 17, 2021, 07:14:24 pm
content: Quote from: Towger on September 16, 2021, 08:05:04 pmShe does really well for her age!Years ago when I was a teenager, I bought a Graviner fire detector unit. They were being sold mail order in one of the amateur electronics magazines, I think described as hotel fire detectors. It had a nice thick curved stainless steel enclosure with a window. I had ideas of using it as a digital clock case as well as being interested in what was inside. Unfortunately the flange was folded and crimped closed and I did too much damage getting it open. Inside was a photomultiplier tube, resistor ladder and some sort of gas trigger tube, the whole thing in encased in low melting point wax. Not as exciting as I hoped.The bits got thrown in a drawer in my bedroom... and eventually, my garage. It was a few years after I owned my own house that I built a sensitive end-window Geiger counter and looked around for something to test it on. Going through my junk drawers in the garage, I suddenly came across a surprisingly hot target in the said drawer. It turned out that what I thought was a blob of paint on the side of the gas trigger tube was actually rather nasty. Luckily it was a waxy consistency and not at all powdery so there were no other traces. It had obviously been applied to theoutsideof the glass as an ionisation source.It just goes to show that not all 'nasties' come in enclosures that display the appropriate warning signs. It was only with the advent of the internet (and then some) before I found that Graviner make fire detection systems for aircraft, including engine bays and other hostile environments and absolutely nothing to do with hotels!EDIT: Yikes, there are still a few around, but it's probably wisest not to post links.