Model Boat Mayhem - Forum

Mess Deck: General Section => Chit-Chat => Topic started by: funtimefrankie on October 04, 2007, 09:20:13 PM

Title: Radar
Post by: funtimefrankie on October 04, 2007, 09:20:13 PM
I know roughly how radar works. But how does it show an allround "picture" when it is mounted half way up a mast? Don't you get a shadow where the mast is? Or if my plan for Nangee tug is right it is mounted on the wheel house roof below the level of the hand rails, compass and mast. Does it not show all this things on the screen?
Any real sailors out there enlighten me?

Frank
Title: Re: Radar
Post by: PSSHIPS on October 04, 2007, 09:24:11 PM
Hi funtime, in the case you are describing the mast behind the radar and any ships structure emediately  in front of the scanner, feeds back as what is known as a "black ark" Which basically when you are looking at the radar screen on say the bridge, is a black segment in the display. Bit like looking down on a cut up pie? ;)

 I hope this helps, Paul...
Title: Re: Radar
Post by: PSSHIPS on October 04, 2007, 10:05:57 PM
PS, it can also be called a "blind ark" ;)
Title: Re: Radar
Post by: JayDee on October 04, 2007, 10:53:34 PM
Hello,
The Radar antenna is turned off where a "shadow" would occur, such as pointing at the Wheelhouse, or a Mast.
This off period will also protect the Crew from extreme radiation from the antenna.
While serving in the Army as a Radar Operator, we used to warm our hands by placing them into the radar beam!! - - early form of Microwave !!.
One Xmas we set up a Xmas tree in the middle of the Square, decorated it with dozens of small neon bulbs, started up the Radar and lit up all the bulbs with the radiation.
Scanning the beam past the tree turned the bulbs on and off
Dead funny to see all those folk trying to figure out where the "electricity" was coming from !.
We never did tell them !!
John.  :)  :)  :)
Title: Re: Radar
Post by: Colin Bishop on October 04, 2007, 10:58:49 PM
Radars can have other effects as well. It is quite well documented that yacht GPS receivers sometimes go haywire in Portsmouth harbour due to the weak GPS signals being overwhelmed by the powerful naval radars. Also I've heard it said that when entering Portsmouth in a small boat you should wear iron knickers for the sake of your grandchildren.
Title: Re: Radar
Post by: JayDee on October 04, 2007, 11:01:24 PM
Colin,
Radars are possibly why I have three sons ,BUT, no daughters !!!!!!!!!!!!.
John.  ::)
Title: Re: Radar
Post by: PSSHIPS on October 04, 2007, 11:13:52 PM
Try being ontop of a funnel when the ship accross the jetty from you flashes up their SPS 49 in air search mode hi beam, now that is suntan! 8)
Title: Re: Radar
Post by: JayDee on October 04, 2007, 11:25:44 PM
Hello,
We were running  3000 Megs, at 250 Kilo watts, not exacty battery powered!!!.
John.  ;)
Title: Re: Radar
Post by: PSSHIPS on October 04, 2007, 11:27:23 PM
Thats what I mean John, fried bollox! :) Thats if you are unlucky! Fried brains otherwise eh? 8)
Title: Re: Radar
Post by: JayDee on October 04, 2007, 11:39:14 PM
Hello,
Thats the problem, nothing visible, but by the time you feel the heat, its too late.
There were some large trees at the end of the Radar bays in camp, we could bring the leaves off them in the summer, they are probably all dead now !!.
But nobody warned us, or told us how dangerous the radiation could be, only warning notice was on top of the Van, saying that the dish could move without warning, nothing else.

John.  :)
Title: Re: Radar
Post by: PSSHIPS on October 04, 2007, 11:45:54 PM
Thats the one, we had something called a "RAD HAZ" system, it meant when you went aloft, either up a mast or funnel, your ship, plus any in the vacinty, ie inboard or outboard or accross a jetty could not flash up anything like radars, boilers or engines, while you were up there, trouble is some ships from abroad didn't keep to the rules and did what they wanted all the time. Portland harbour was a cracker for loosing your balls.

 In more cases than one most of the time and Guz could be dodgy too!

 If in doubt, decend rapidly! ;) We did, it was January at the time, but, felt like summer on Mercury! :)
Title: Re: Radar
Post by: Colin Bishop on October 05, 2007, 08:50:48 AM
Quote
Radars are possibly why I have three sons ,BUT, no daughters !!!!!!!!!!!!.

I've got two daughters, I must have been going the other way but not quite so fast.....
Title: Re: Radar
Post by: OneBladeMissing on October 05, 2007, 07:49:24 PM
Radars can have other effects as well. It is quite well documented that yacht GPS receivers sometimes go haywire in Portsmouth harbour due to the weak GPS signals being overwhelmed by the powerful naval radars. Also I've heard it said that when entering Portsmouth in a small boat you should wear iron knickers for the sake of your grandchildren.

The words Portsmouth and 'iron knickers' in the same sentence!
Hello sailor!
Title: Re: Radar
Post by: PSSHIPS on October 05, 2007, 07:50:57 PM
indeed! ;) :) :P :kiss:
Title: Re: Radar
Post by: Colin Bishop on October 05, 2007, 08:23:07 PM
Personal experience?  ;D
Title: Re: Radar
Post by: PSSHIPS on October 05, 2007, 08:27:38 PM
Not at all Colin, you raised it, so we all assumed it was your own personal experience? :o ???
Title: Re: Radar
Post by: Colin Bishop on October 05, 2007, 08:33:46 PM
I wish!
Title: Re: Radar
Post by: PSSHIPS on October 05, 2007, 08:38:28 PM
Each to his own Colin, but, those knickers must chaffe a bit eh? How do you? Well, ya'know?? Do you have to have a welder on stanby all the time? Must cost a fortune? ;) I hope you have got some good cream for them?
 I hear Vasaline is pretty good? :)
Title: Re: Radar
Post by: watersnail on October 09, 2007, 10:55:21 PM
        Just read thru this Jay Dee ,dont tell me you are ex Green Archer toooooo fgs.nah you must be off the old 3 Mark 7s  LOL
               Tis true tho on Hohne Ranges we could set light to baccy tin of petrol at 30 feet on high power !
                    ! wont have a microwave oven in the house !!
         
Title: Re: Radar
Post by: JayDee on October 09, 2007, 11:02:50 PM
Hello,
 Yes, 3 Mk7 was my set, Green Archer indeed !, real softies set that was !.
I was with the RA at Celle, a 2 1/2 year NS man, got caught with the Cuban Missile setup AND the Berlin Wall, I was sure they would start a War before I got out !!!.
Did you enjoy your trips to Hohne ???.
John.  ;)  ;)  ;)
Title: Re: Radar
Post by: watersnail on October 10, 2007, 10:24:40 AM


    WoW Must have been you who polished the brass door handle and made a puddle by the steps for us poor Virgin 17 yr olds !
         Still had 3 Mark 7s when i was there in 62,light on all morning dish moving slightly,door opens and a Gang of NS emerge with the fag smoke,coffee smell and still arguing about 3 card brag PMSL,NS guy taught me how to drive a Matador towing the genny,great  days Jay Dee,must have hit the only tree on Hohne ranges!Do u get the 94 Everywhere Mag ?
Title: Re: Radar
Post by: JayDee on October 10, 2007, 12:16:31 PM
Hello Alex,
I broke completely from the Army when demobbed, never claimed any Credits, burned all letters etc, didn't want to be in, very glad to get out.
Threatened my 3 sons with broken legs IF they joined the Forces and meant it too !!!.
John. :)
Title: Re: Radar
Post by: watersnail on October 10, 2007, 01:18:16 PM
 Ohh John i had to stay in ! My dad was at sea on Union Castle Line i was left at home wif Mum and 3 sisters !! Two older one younger,house was like a blooming fashion show ! Did 10 yrs RA then transfered for last two to Army Air Corps My late father in law was National Service fellow,did nearly four years ! Kept going awol,lol spent his time mostly in Colchester !Time in glasshouse and awol was added on to his service each time.......Have to build boats she wont let me build Artillery or Radars ??  Alex
Title: Re: Radar
Post by: farrow on November 02, 2007, 10:26:22 PM
Normal ship radar is not that powerful to do great harm to humans, or though prolong exposure , there is no real info a bit like mobile phones and the brain cooking theory. The dangerous stuff is Naval I believe X ray band which is used for their weapon systems used to search for incoming whatever, this is not allowed to be used supposedly within about 30 miles from the coast. When I was duty in Harbour Control Portsmouth (semaphore tower), a dutch ship came alongside South Railway jetty, she had forgot to shut her system down. All the computers in the building went haywire, the port CCTV systems shut down and the senior Naval Officer in the building went ape. Getting back to your thread, yes there is interference from vessel structures especially the funnel. These objects block the signal causing a blind sector. This area is noted when the system is installed in the vessel and put in the handbook for the system on the bridge. The RMAS Arrochar had her radar aerial mounted in front of the mast and funnel, but there was hardly any interference. Ro Ro ferries and large container ships often have a extra radar with the radar aerial fitted aft to get round this problem. The TS Royalist has a radar aerial on her accommodation top which is 5 ft of the deck and this is consider safe for the young cadets.
Title: Re: Radar
Post by: farrow on November 04, 2007, 10:11:31 PM
The only radar in Portsmouth Harbour which would do such a thing as sitch of computerts, interfere with GPS and affect yoyr virality is the big search radars. These by regulation and I believe law are not aloowed to transmit within 20/30 miles of land. The normal Navigation radars have no such effect, or though no one likes to stand in front close to them, because of similiar claims with mobile phones affecting peoples brains. Getting back to the thread, yes close metal objects such as masts and funnels cause blind spot arcs on the viewing screen, that is why RoRo ferries must have a seperate radar system with its aerial aft covering the stern arc also some large box boats carry stern radrs for the same reason.
Title: Re: Radar
Post by: Bartapuss on November 04, 2007, 11:31:29 PM
Hey PSSHIP, never mind tagout lockout and work aloft permits, when some nutter  decides he wants to switch on those 1022 antennas sure start to turn dead quickly, if you're lucky just enough time to hit the deck and eat steel  >>:-( >>:-(
Title: Re: Radar
Post by: HS93 (RIP) on November 04, 2007, 11:41:03 PM
Hey PSSHIP, never mind tagout lockout and work aloft permits, when some nutter  decides he wants to switch on those 1022 antennas sure start to turn dead quickly, if you're lucky just enough time to hit the deck and eat steel  >>:-( >>:-(

  I think you will find he is now DARLEK1

   HS93
Title: Re: Radar
Post by: Colin Bishop on November 04, 2007, 11:50:39 PM
Quote
I think you will find he is now DARLEK1

That's what standing in front of an X band radar does to you!  ;)