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This is the Conversation Forum for Ask the h2g2 Community << Exclamation Marks!!!!!!!!!!!!!!!!!!!!!!!!!! The loveliest island? >> Subject: Radios in tunnels Posted Sep 26, 2001 by Anonymouse (40077) This is a reply to this Posting   Posting 41 That's something else I am rather relieved to say I never did.. Compuserve or AOL or the like. I aquired internet access at the same time as the local BBS (which has since become the #1 and only long-lived ISP in the area... though '#1' isn't saying much ;-/ ... though RR has made it here now... at 4 times what I'm paying per month) did. Read the First Reply to this Posting Subject: Radios in tunnels Posted Oct 11, 2001 by Mistdancer - X - Sporadically Coherent This is a reply to this Posting   Posting 42 Can't remember the first site I visited...all of 18 months ago!! But now my other half moans that I've taken over all the computers in the house (all 3) and that every time he boots up, all the browsers think it's me! Oh, and the My Docs folder is bigger than Windows! He's also amazed at how fast I've filled 60 Gb of hard drive space!!! Read the First Reply to this Posting Subject: Radios in tunnels Posted Oct 12, 2001 by Xanatic, juice for Allah This is a reply to this Posting   Posting 43 60 giga? I didn't even know you could get them that big yet. But remember the time it takes to fill up the hardisk is inversely proportional to the size of it. The bigger the harddisk, the faster it goes. Read the First Reply to this Posting Subject: Radios in tunnels Posted Oct 12, 2001 by Mistdancer - X - Sporadically Coherent This is a reply to this Posting   Posting 44 The 60 Gb is split between 3 computers....20Gb each! They're networked, so I can spread my stuff over them all, without leaving the comfort of my chair! Read the First Reply to this Posting Subject: Radios in tunnels Posted Nov 3, 2001 by Ollie Brennan This is a reply to this Posting   Posting 45 It's all about waveguides and cavities. The tunnel acts as a waveguide for the EM waves, it was in our lectures, but at the corner the waveguide is no longer straight so the EM waves interfere to obviously give a bit of a reception. The same concept also explains why you lose MW/LW reception going under (say) a bridge or something, but not FM waves which carry their information by modulating frequency which can be received in these cases. Amplitude modulation is affected. I've got loads of info about all this somewhere, but I can't be bothered to find it all. Read the First Reply to this Posting Subject: Radios in tunnels Posted Nov 3, 2001 by Cakewalker This is a reply to this Posting   Posting 46 not even for friendly fellow researchers? It's a subject close to our hearts - if you're a proper researcher you go through a great many tunnels. Read the First Reply to this Posting Subject: Radios in tunnels Posted Nov 12, 2001 by Peregrin This is a reply to this Posting   Posting 47 I thought it was all to do with the evil radiowave-eating gremlins? Ah well, another childhood belief smashed. Subject: Radios in tunnels Posted Nov 24, 2001 by Big Geordie This is a reply to this Posting   Posting 48 When I used to be a sailor (no jokes please) We used to use hand held radios to keep in contact with control. These worked deep in the bowels of the ship. So the argument that radios don't work underground does'nt stand up. There is a possibility that at the corner the structural steelwork is closer together and is the same distance as the frequency of the signal that it is transmitted down the steel supports into the tunnel. The rest of the tunnel does not match the frequency so the signal does not travel to the receiver in the tunnel. But I might be wrong, again There is probably a better explanation out there. there is plenty of egg heads in H2 maybe they can answer this one. Subject: Radios in tunnels Posted Nov 25, 2001 by Anonymouse (40077) This is a reply to this Posting   Posting 49 They do make 60G drives now. My pop got one with his new machine -- right outta da box. Would make me jealous if it was a dell or custom (with a WD drive) instead of an HP Pavillion. Subject: Radios in tunnels Posted Sep 1, 2002 by Rojo Habe (48-1+2-7) This is a reply to this Posting   Posting 50 ...an unshielded coaxial cable?? Wouldn't that be, like, just a piece of wire? Read the First Reply to this Posting Subject: Radios in tunnels Posted Sep 1, 2002 by Captain_SpankMunki [Keeper & Former ACE] Thanking <Diety of choice> for the joy of Goo. This is a reply to this Posting   Posting 51 LOL! Liam. <- Who can't believe he used LOL. Read the First Reply to this Posting Subject: Radios in tunnels Posted Sep 10, 2002 by Captain_SpankMunki [Keeper & Former ACE] Thanking <Diety of choice> for the joy of Goo. This is a reply to this Posting   Posting 52 Having spoken to someone in authority on the Blackwall tunnel project - namely my dad - I have made an important discovery regarding the original question. The corners of the Blackwall tunnel are where the vents are. It's clear air above you - with a little filtering and a couple of big fans. Liam. Subject: Radios in tunnels Posted Apr 2, 2003 by Researcher 224056 This is a reply to this Posting   Posting 53 because radio waves are curved they have greater penetrance when you go round corners. Read the First Reply to this Posting Subject: Radios in tunnels Posted Apr 3, 2003 by Whisky This is a reply to this Posting   Posting 54 Radio waves? Curved??? Read the First Reply to this Posting Subject: Radios in tunnels Posted Apr 3, 2003 by Wand'rin star This is a reply to this Posting   Posting 55 This brought back some happy memories. Why did you choose to revive it, 22056? If you put something in your space, lots of us could communicate with you. Read the First Reply to this Posting Subject: Radios in tunnels Posted Apr 3, 2003 by Captain_SpankMunki [Keeper & Former ACE] Thanking <Diety of choice> for the joy of Goo. This is a reply to this Posting   Posting 56 Yes, didn't you know Whisky? It curves up, then levels off and starts curving back down again. This is why some aerials have a curly bit at the bottom, for the penetrance - something to do with 5 people in a state no doubt. Liam. Read the First Reply to this Posting Subject: Radios in tunnels Posted Apr 4, 2003 by Potholer This is a reply to this Posting   Posting 57 *Please* let's not get into discussions on antenna design - at the best of times it's rather a black art, and most of the time it's much worse. Read the First Reply to this Posting Subject: Radios in tunnels Posted Apr 4, 2003 by Captain_SpankMunki [Keeper & Former ACE] Thanking <Diety of choice> for the joy of Goo. This is a reply to this Posting   Posting 58 Antenna design is superb! "Right so if I angle this bit at 34 degrees I get +24dB compared to 33 degrees." Liam. Conversation list Most of the content on h2g2 is created by h2g2's Researchers, who are members of the public. The views expressed are theirs and unless specifically stated are not those of the BBC. The BBC is not responsible for the content of any external sites referenced. 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