Andthere's a referencethatwouldbelostonmostoftheaudience.
Allright, wegottwostations.
Fantastic.
Sothebusinessendisactually a ll.
Thisisdoinghisamplifierandstuffforthestation.
Downthebeach, boyslastNorman's Colin.
Oh, hi.
Perfect.
Isthatso?
Thisis a Londonstay.
She'llpullabsoluteon.
Thisisallcomingoutof a penny.
Tinywireon a pennyonourpennyisactingas a dialoguerectifyingthesignal.
Andwe'repickingup a stationcalledAbsoluteradioallthewayfromLondonon a pieceofwirehungoutofmyoffice, whichisactingasanantenna.
Andactually, ifwedidn't havethison, wehad a pairofheadphones.
Thisthingwouldworkwithnopowersource.
Philip.
What?
You'relike a highpoweredphysicist.
Whatareyoudoingmessingaroundwiththis?
Soitallgoesbackabouthowmanyyearswouldbe 41 years?
41 yearstothisbook?
Thisbookwasactuallypublishedin 1972 onDDE.
ThisiswhereforMayphysicsstarted.
MyUncleBennywas a radioamateur, reallyinterestedinshortwaveradioandlisteningtoshortwaveradiobuilding.
AndTurner's gettingbettersignals.
See, and I, when I wasabout 10 usethisbooktobuildsomethingwhichiscalled a crystalradio.
Sowe'vegot a coil, whichisaninducther.
We'vegot a capacitor, whichweconsumesowecanchangethecapacitance, a dialogue, whichissomethingcalled a Rectifier, whichmeansthatonlyletscurrentflowonewayonthepairofheadphones.
IsthistheactualbookorthisisThisis I reallywish I hadtheactualbook.
I suspectif I hadtheactualbook, itwouldn't quitebeinthisgood a quality.
There's a wholenewseriesofLadybirdbooks, bytheway, thatsomeofyoumighthaveseenprettygoodthezombieapocalypse, mindfulnessandbestofall, thestudentLisafinds a revisiontimetableverytiring.
Sowhen I initiallybuiltthisallthoseyearsago, weusedsomethingwhichiscalled a silicondialledimportantthingwiththisisitonlyallowscurrenttoflowoneway, andsoinsteadofit's sloshingbackandforthlikethis, it's just a loanittoflowinonedirection.
Theradiowaveitselfis a combinationofwhat's called a carrierwave, whichisveryhighfrequency, maybe a 1,000,000 timesgoingbackandforth, maybe a 1,000,000 times a secondelectricfieldflippingbackandforthmegahertz.