Ì«×ÓүС˵Íø > Ó¢Óïµç×ÓÊé > the dawn of amateur radio in the u[1].k.(ÊÕÒô»ú³ûÐεĵ®Éú) >

µÚ25½Ú

the dawn of amateur radio in the u[1].k.(ÊÕÒô»ú³ûÐεĵ®Éú)-µÚ25½Ú


°´¼üÅÌÉÏ·½Ïò¼ü ¡û »ò ¡ú ¿É¿ìËÙÉÏÏ·­Ò³£¬°´¼üÅÌÉ쵀 Enter ¼ü¿É»Øµ½±¾ÊéĿ¼ҳ£¬°´¼üÅÌÉÏ·½Ïò¼ü ¡ü ¿É»Øµ½±¾Ò³¶¥²¿£¡
¡ª¡ª¡ª¡ªÎ´ÔĶÁÍꣿ¼ÓÈëÊéÇ©ÒѱãÏ´μÌÐøÔĶÁ£¡




transmitter¡¡¡¡¡¡hall¡¡¡¡¡¡by¡¡¡¡¡¡dropping¡¡¡¡¡¡one¡¡¡¡¡¡of¡¡¡¡¡¡the¡¡¡¡¡¡antenna¡¡¡¡¡¡towers¡¡¡¡¡¡onto¡¡¡¡¡¡it£»¡¡¡¡¡¡but¡¡¡¡¡¡the¡¡

equipment¡¡was¡¡not¡¡damaged¡£¡¡

¡¡¡¡¡¡¡¡¡¡¡¡¡¡They¡¡¡¡¡¡were¡¡¡¡¡¡more¡¡¡¡¡¡successful¡¡¡¡¡¡at¡¡¡¡¡¡the¡¡¡¡¡¡Royal¡¡¡¡¡¡Navy¡¡¡¡¡¡transmitting¡¡¡¡¡¡site¡¡¡¡¡¡at¡¡

Votanikos¡£¡¡¡¡¡¡Here¡¡¡¡¡¡they¡¡¡¡¡¡tried¡¡¡¡¡¡to¡¡¡¡¡¡destroy¡¡¡¡¡¡six¡¡¡¡¡¡300¡¡¡¡¡¡foot¡¡¡¡¡¡tubular¡¡¡¡¡¡masts¡£¡¡¡¡¡¡One¡¡

remained¡¡standing¡¡and¡¡also¡¡the¡¡lower¡¡part¡¡of¡¡another¡£¡¡All¡¡the¡¡test¡¡gear¡¡in¡¡

the¡¡lab¡¡was¡¡thrown¡¡out¡¡of¡¡a¡¡second¡¡floor¡¡window¡¡and¡¡burnt¡£¡¡I¡¡was¡¡acting¡¡

as¡¡¡¡¡¡official¡¡¡¡¡¡photographer¡¡¡¡¡¡for¡¡¡¡¡¡my¡¡¡¡¡¡unit¡¡¡¡¡¡at¡¡¡¡¡¡the¡¡¡¡¡¡time¡£¡¡¡¡¡¡When¡¡¡¡¡¡I¡¡¡¡¡¡walked¡¡¡¡¡¡into¡¡¡¡¡¡a¡¡

small¡¡store¡¡room¡¡I¡¡saw¡¡all¡¡the¡¡equipment¡¡had¡¡been¡¡thrown¡¡off¡¡the¡¡shelves¡¡

on¡¡¡¡¡¡to¡¡¡¡¡¡the¡¡¡¡¡¡floor£»¡¡¡¡¡¡but¡¡¡¡¡¡appeared¡¡¡¡¡¡to¡¡¡¡¡¡be¡¡¡¡¡¡intact¡£¡¡¡¡¡¡I¡¡¡¡¡¡spotted¡¡¡¡¡¡a¡¡¡¡¡¡box¡¡¡¡¡¡of¡¡¡¡¡¡brand¡¡¡¡¡¡new¡¡

packed¡¡German¡¡navy¡¡morse¡¡keys¡¡and¡¡decided¡¡the¡¡time¡¡had¡¡come¡¡for¡¡me¡¡to¡¡

acquire¡¡a¡¡small¡¡war¡¡trophy¡¡of¡¡my¡¡own¡£¡¡As¡¡I¡¡bent¡¡down¡¡to¡¡pick¡¡up¡¡a¡¡key£»¡¡I¡¡

was¡¡horrified¡¡to¡¡see¡¡two¡¡large¡¡sticks¡¡of¡¡gelignite¡¡perched¡¡perilously¡¡on¡¡the¡¡

edge¡¡of¡¡a¡¡shelf¡£¡¡The¡¡explosive¡¡was¡¡tied¡¡with¡¡white¡¡ribbon£»¡¡with¡¡a¡¡weight¡¡

attached¡¡to¡¡the¡¡other¡¡end¡£¡¡I¡¡froze¡¡to¡¡the¡¡spot¡£¡¡Gingerly¡¡I¡¡lifted¡¡my¡¡trophy¡¡

out¡¡of¡¡the¡¡box¡¡and¡¡began¡¡to¡¡walk¡¡slowly¡¡backwards£»¡¡being¡¡very¡¡careful¡¡not¡¡

to¡¡knock¡¡anything¡¡over¡£¡¡I¡¡breathed¡¡a¡¡sigh¡¡of¡¡relief¡¡when¡¡I¡¡was¡¡out¡¡of¡¡the¡¡

room¡¡¡¡¡¡and¡¡¡¡¡¡immediately¡¡¡¡¡¡alerted¡¡¡¡¡¡the¡¡¡¡¡¡engineers¡¡¡¡¡¡who¡¡¡¡¡¡came¡¡¡¡¡¡and¡¡¡¡¡¡defused¡¡¡¡¡¡the¡¡

booby¡¡¡¡¡¡trap¡£¡¡¡¡¡¡So¡¡¡¡¡¡this¡¡¡¡¡¡book¡¡¡¡¡¡might¡¡¡¡¡¡never¡¡¡¡¡¡have¡¡¡¡¡¡been¡¡¡¡¡¡written¡¡¡¡¡¡thanks¡¡¡¡¡¡to¡¡¡¡¡¡the¡¡

German¡¡army¡£¡¡

¡¡¡¡¡¡¡¡¡¡¡¡¡¡At¡¡the¡¡Athens¡¡broadcasting¡¡station¡¡transmitter¡¡site¡¡at¡¡Liosia¡¡my¡¡unit¡¡

erected¡¡a¡¡small¡¡temporary¡¡'T'¡¡antenna¡¡which¡¡allowed¡¡the¡¡station¡¡to¡¡come¡¡

on¡¡the¡¡air¡¡again£»¡¡but¡¡a¡¡short¡¡time¡¡later£»¡¡when¡¡the¡¡ELAS¡¡guerrillas¡¡overran¡¡

the¡¡area¡¡they¡¡began¡¡using¡¡the¡¡transmitter¡¡to¡¡broadcast¡¡their¡¡own¡¡view¡¡of¡¡

events¡£¡¡¡¡¡¡We¡¡¡¡¡¡provided¡¡¡¡¡¡the¡¡¡¡¡¡broadcasting¡¡¡¡¡¡authority¡¡¡¡¡¡with¡¡¡¡¡¡a¡¡¡¡¡¡BC¡¡¡¡¡¡610¡¡¡¡¡¡mobile¡¡

transmitter¡¡installed¡¡next¡¡to¡¡the¡¡Parliament¡¡building¡¡in¡¡the¡¡centre¡¡of¡¡town£»¡¡



¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡85¡¡


¡­¡¡Page¡¡86¡­

¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡The¡¡dawn¡¡of¡¡amateur¡¡radio¡¡in¡¡the¡¡U¡£K¡£¡¡and¡¡Greece¡¡£º¡¡a¡¡personal¡¡view¡¡



using¡¡¡¡¡¡¡¡¡¡the¡¡¡¡same¡¡¡¡¡¡¡¡¡¡frequency¡¡¡¡¡¡¡¡¡¡of¡¡¡¡610¡¡¡¡¡¡¡¡KHz¡£¡¡¡¡¡¡¡¡¡¡Listeners¡¡¡¡¡¡¡¡in¡¡¡¡Cairo¡¡¡¡¡¡¡¡couldn't¡¡

understand¡¡¡¡¡¡what¡¡¡¡¡¡was¡¡¡¡¡¡going¡¡on¡¡¡¡¡¡when¡¡¡¡¡¡one¡¡¡¡¡¡moment¡¡¡¡¡¡they¡¡¡¡heard¡¡¡¡¡¡an¡¡¡¡¡¡official¡¡

government¡¡announcement¡¡and¡¡a¡¡little¡¡later¡¡a¡¡war¡¡communique¡¡issued¡¡by¡¡

the¡¡Communist¡¡guerrillas¡£¡¡



¡¡¡¡¡¡¡¡¡¡8¡£¡¡Over¡­the¡­horizon¡¡or¡¡Ionospheric¡¡HF¡¡Radar¡¡¡­¡¡OTHR¡¡

¡¡¡¡¡¡¡¡¡¡¡¡¡¡As¡¡mentioned¡¡briefly¡¡in¡¡Chapter¡¡1£»¡¡it¡¡was¡¡in¡¡April¡¡1976¡¡that¡¡the¡¡then¡¡

Soviet¡¡¡¡¡¡Union¡¡¡¡¡¡first¡¡¡¡¡¡unleashed¡¡¡¡¡¡a¡¡¡¡¡¡diabolical¡¡¡¡¡¡noise¡¡¡¡¡¡on¡¡¡¡¡¡the¡¡¡¡¡¡HF¡¡¡¡¡¡bands¡¡¡¡¡¡which¡¡

caused¡¡widespread¡¡interference¡¡to¡¡all¡¡broadcasting¡¡and¡¡telecommunication¡¡

services¡¡¡¡¡¡between¡¡¡¡¡¡6¡¡¡¡¡¡and¡¡¡¡¡¡20¡¡¡¡¡¡MHz¡£¡¡¡¡¡¡On¡¡¡¡¡¡the¡¡¡¡¡¡¡¡¡¡¡¡¡¡first¡¡¡¡¡¡day¡¡¡¡¡¡the¡¡¡¡¡¨knock¡­knock¡­¡¡

knock¡¨¡¡¡¡¡¡went¡¡¡¡¡¡on¡¡¡¡¡¡continuously¡¡¡¡¡¡for¡¡¡¡¡¡over¡¡¡¡¡¡ten¡¡¡¡¡¡hours¡£¡¡¡¡¡¡Radio¡¡¡¡¡¡amateurs£»¡¡¡¡¡¡who¡¡

were¡¡among¡¡the¡¡services¡¡that¡¡suffered¡¡from¡¡the¡¡interference£»¡¡soon¡¡came¡¡to¡¡

call¡¡this¡¡noise¡¡¡¨the¡¡woodpecker¡¨¡£¡¡By¡¡rotating¡¡their¡¡beams¡¡when¡¡tuned¡¡to¡¡

the¡¡¡¡¡¡14¡¡¡¡¡¡MHz¡¡¡¡¡¡band¡¡¡¡¡¡¡¡¡¡¡¡they¡¡¡¡¡¡established¡¡¡¡¡¡¡¡that¡¡¡¡¡¡the¡¡¡¡transmissions¡¡¡¡¡¡appeared¡¡¡¡¡¡¡¡¡¡¡¡to¡¡

originate¡¡from¡¡the¡¡vicinity¡¡of¡¡the¡¡town¡¡of¡¡Gomel¡¡in¡¡the¡¡U¡£S¡£S¡£R¡£¡¡

¡¡¡¡¡¡¡¡¡¡¡¡¡¡The¡¡¡¡¡¡¡¡¡¡governments¡¡¡¡¡¡¡¡¡¡¡¡¡¡of¡¡¡¡¡¡many¡¡¡¡¡¡¡¡¡¡¡¡countries¡¡¡¡¡¡¡¡¡¡world¡­wide¡¡¡¡¡¡¡¡¡¡¡¡immediately¡¡

protested¡¡to¡¡Moscow£»¡¡and¡¡all¡¡they¡¡got¡¡in¡¡reply¡¡was¡¡a¡¡brief¡¡statement¡¡that¡¡

the¡¡U¡£S¡£S¡£R¡£¡¡was¡¡carrying¡¡out¡¡¡¨an¡¡experiment¡¨¡£¡¡

¡¡¡¡¡¡¡¡¡¡¡¡¡¡The¡¡reason¡¡for¡¡the¡¡very¡¡strong¡¡on/off¡¡pulses¡¡was¡¡probably¡¡because£»¡¡at¡¡

first£»¡¡¡¡¡¡the¡¡¡¡¡¡Russians¡¡¡¡¡¡were¡¡¡¡¡¡using¡¡¡¡¡¡existing¡¡¡¡¡¡radar¡¡¡¡¡¡antennas¡¡¡¡¡¡which¡¡¡¡¡¡permit¡¡¡¡¡¡the¡¡

transmitting¡¡¡¡¡¡and¡¡¡¡¡¡receiving¡¡¡¡¡¡functions¡¡¡¡¡¡to¡¡¡¡¡¡share¡¡¡¡¡¡the¡¡¡¡¡¡same¡¡¡¡¡¡antenna¡£¡¡¡¡¡¡Modern¡¡

OTHR¡¡¡¡installations¡¡have¡¡¡¡¡¡different¡¡¡¡¡¡transmitting¡¡¡¡¡¡and¡¡¡¡¡¡receiving¡¡¡¡¡¡sites£»¡¡¡¡often¡¡

located¡¡many¡¡miles¡¡apart¡£¡¡

¡¡¡¡¡¡¡¡¡¡¡¡¡¡From¡¡the¡¡early¡¡1950s¡¡pulsed¡¡oblique¡¡ionosphere¡¡sounders¡¡had¡¡shown¡¡

that¡¡the¡¡normal¡¡ionosphere¡¡is¡¡much¡¡more¡¡stable¡¡than¡¡had¡¡previously¡¡been¡¡

thought¡¡to¡¡be¡£¡¡The¡¡physical¡¡reason¡¡for¡¡this¡¡is¡¡that¡¡the¡¡incredibly¡¡tenuous¡¡

ionized¡¡¡¡¡¡gas¡¡¡¡¡¡which¡¡¡¡¡¡does¡¡¡¡¡¡the¡¡¡¡¡¡reflecting¡¡¡¡¡¡has¡¡¡¡¡¡a¡¡¡¡¡¡molasses¡­like¡¡¡¡¡¡viscosity¡£¡¡¡¡¡¡Of¡¡

course£»¡¡there¡¡are¡¡daily¡¡and¡¡seasonal¡¡changes£»¡¡but¡¡over¡¡limited¡¡periods¡¡of¡¡

half¡¡an¡¡hour¡¡or¡¡so£»¡¡the¡¡F¡¡layer¡¡at¡¡a¡¡given¡¡location¡¡is¡¡actually¡¡quite¡¡well¡­¡¡

behaved¡£¡¡It¡¡bounces¡¡back¡¡signals¡¡in¡¡a¡¡nearly¡¡constant¡¡direction¡¡and¡¡with¡¡

nearly¡¡¡¡¡¡¡¡¡¡constant¡¡¡¡¡¡¡¡amplitude¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡just¡¡¡¡¡¡what¡¡¡¡¡¡¡¡is¡¡¡¡required¡¡¡¡¡¡¡¡for¡¡¡¡¡¡good¡¡¡¡¡¡¡¡radar¡¡

performance¡£¡¡

¡¡¡¡¡¡¡¡¡¡¡¡¡¡Over¡­the¡­horizon¡¡HF¡¡radars¡¡use¡¡the¡¡ionosphere¡¡as¡¡a¡¡kind¡¡of¡¡mirror¡¡to¡¡

¡¨see¡¨¡¡around¡¡the¡¡curvature¡¡of¡¡the¡¡earth¡£¡¡They¡¡have¡¡a¡¡variety¡¡of¡¡uses£»¡¡both¡¡



¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡86¡¡


¡­¡¡Page¡¡87¡­

¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡The¡¡dawn¡¡of¡¡amateur¡¡radio¡¡in¡¡the¡¡U¡£K¡£¡¡and¡¡Greece¡¡£º¡¡a¡¡personal¡¡view¡¡



military¡¡¡¡¡¡¡¡¡¡and¡¡¡¡¡¡civilian¡£¡¡¡¡¡¡And¡¡¡¡¡¡¡¡they¡¡¡¡¡¡have¡¡¡¡¡¡the¡¡¡¡¡¡advantage¡¡¡¡¡¡¡¡¡¡over¡¡¡¡¡¡line¡­of¡­sight¡¡

microwave¡¡radars¡¡of¡¡being¡¡able¡¡to¡¡cover¡¡enormous¡¡areas¡¡with¡¡much¡¡less¡¡

power¡¡and¡¡at¡¡a¡¡fraction¡¡of¡¡the¡¡cost¡¡of¡¡the¡¡latter¡£¡¡

¡¡¡¡¡¡¡¡¡¡¡¡¡¡A¡¡¡¨relocatable¡¨¡¡OTHR¡¡system¡¡can¡¡track¡¡aircraft¡¡targets¡¡right¡¡down¡¡to¡¡

ground¡¡level¡£¡¡In¡¡an¡¡early¡¡experiment¡¡operators¡¡were¡¡puzzled¡¡by¡¡the¡¡sudden¡¡

disappearance¡¡from¡¡their¡¡screen¡¡of¡¡an¡¡aircraft¡¡they¡¡had¡¡been¡¡tracking¡¡as¡¡it¡¡

taxied¡¡¡¡¡¡along¡¡¡¡¡¡the¡¡¡¡¡¡ground¡£¡¡¡¡¡¡They¡¡¡¡¡¡found¡¡¡¡¡¡out¡¡¡¡¡¡later¡¡¡¡¡¡that¡¡¡¡¡¡the¡¡¡¡¡¡reason¡¡¡¡¡¡for¡¡¡¡¡¡the¡¡

disappearance¡¡was¡¡that¡¡the¡¡aircraft¡¡had¡¡gone¡¡into¡¡a¡¡metal¡¡hangar¡¡which¡¡did¡¡

not¡¡show¡¡on¡¡the¡¡screen¡¡because¡¡it¡¡was¡¡not¡¡in¡¡motion£»¡¡as¡¡explained¡¡below¡£¡¡

¡¡¡¡¡¡¡¡¡¡¡¡¡¡In¡¡¡¡¡¡1979¡¡¡¡¡¡the¡¡¡¡¡¡United¡¡¡¡¡¡States¡¡¡¡¡¡Air¡¡¡¡¡¡Force¡¡¡¡¡¡began¡¡¡¡¡¡experimenting¡¡¡¡¡¡with¡¡¡¡¡¡an¡¡

OTHR¡¡system¡¡at¡¡a¡¡site¡¡near¡¡Bangor£»¡¡Maine¡£¡¡Because¡¡HF¡¡frequencies¡¡were¡¡

being¡¡used¡¡the¡¡power¡¡was¡¡kept¡¡very¡¡low¡¡to¡¡minimize¡¡interference¡¡to¡¡other¡¡

services¡¡during¡¡the¡¡early¡¡tests¡£¡¡At¡¡the¡¡time¡¡of¡¡writing¡¡£¨1989£©¡¡it¡¡is¡¡believed¡¡

that¡¡¡¡¡¡a¡¡¡¡¡¡full¡­power¡¡¡¡¡¡relocatable¡¡¡¡¡¡OTHR¡¡¡¡¡¡system¡¡¡¡situated¡¡¡¡¡¡in¡¡Virginia¡¡¡¡¡¡is¡¡¡¡¡¡being¡¡

used¡¡in¡¡the¡¡anti¡­drug¡¡war¡£¡¡

¡¡¡¡¡¡¡¡¡¡¡¡¡¡As¡¡can¡¡be¡¡seen¡¡from¡¡the¡¡map¡¡this¡¡ROTHR¡¡can¡¡cover¡¡a¡¡vast¡¡area¡¡of¡¡

1¡£6¡¡million¡¡nautical¡¡miles£»¡¡straddling¡¡the¡¡whole¡¡Caribbean¡£¡¡The¡¡scan¡¡area¡¡

stretches¡¡¡¡¡¡¡¡¡¡from¡¡¡¡¡¡¡¡the¡¡¡¡coast¡¡¡¡¡¡¡¡of¡¡¡¡Colombia¡¡¡¡¡¡¡¡¡¡¡¡in¡¡¡¡South¡¡¡¡¡¡¡¡America¡¡¡¡¡¡¡¡¡¡¡¡up¡¡¡¡¡¡through¡¡

Nicaragua¡¡¡¡¡¡¡¡¡¡¡¡and¡¡¡¡¡¡¡¡Honduras¡¡¡¡¡¡¡¡¡¡¡¡to¡¡¡¡Florida¡¡¡¡¡¡£¨on¡¡¡¡¡¡its¡¡¡¡west¡¡¡¡¡¡boundary£©¡¡¡¡¡¡¡¡¡¡¡¡and¡¡¡¡¡¡then¡¡

southwards¡¡through¡¡Puerto¡¡Rico£»¡¡to¡¡Trinidad¡¡&¡¡Tobago¡¡and¡¡the¡¡northern¡¡

coast¡¡of¡¡Venezuela¡£¡¡

¡¡¡¡¡¡¡¡¡¡¡¡¡¡But¡¡¡¡¡¡this¡¡¡¡¡¡vast¡¡¡¡¡¡area¡¡¡¡¡¡is¡¡¡¡¡¡not¡¡¡¡¡¡covered¡¡¡¡¡¡continuously£»¡¡¡¡¡¡the¡¡¡¡¡¡system¡¡¡¡¡¡operator¡¡

can¡¡¡¡¡¡provide¡¡¡¡¡¡surveillance¡¡¡¡¡¡in¡¡¡¡¡¡a¡¡¡¡¡¡number¡¡¡¡¡¡of¡¡¡¡¡¡sectors¡¡¡¡¡¡known¡¡¡¡¡¡as¡¡¡¡¡¡DIRs¡¡¡¡¡¡£¨dwell¡¡

information¡¡regions£©¡£¡¡Each¡¡one¡¡of¡¡the¡¡176¡¡DIRs¡¡can¡¡be¡¡¡¨illuminated¡¨¡¡for¡¡

only¡¡¡¡¡¡a¡¡¡¡¡¡few¡¡¡¡¡¡seconds¡¡¡¡¡¡at¡¡¡¡¡¡a¡¡¡¡¡¡time¡£¡¡¡¡¡¡Small¡¡¡¡¡¡aircraft¡¡¡¡¡¡and¡¡¡¡¡¡small¡¡¡¡¡¡vessels¡¡¡¡¡¡can¡¡¡¡¡¡be¡¡

detected¡¡by¡¡an¡¡ingenious¡¡method£»¡¡only¡¡when¡¡they¡¡move¡£¡¡This¡¡is¡¡how¡¡it¡¡is¡¡

done£º¡¡

¡¡¡¡¡¡¡¡¡¡¡¡¡¡At¡¡¡¡¡¡the¡¡¡¡¡¡receiving¡¡¡¡¡¡site¡¡¡¡¡¡of¡¡¡¡¡¡the¡¡¡¡¡¡ROTHR¡¡¡¡¡¡system¡¡¡¡¡¡a¡¡¡¡¡¡very¡¡¡¡¡¡large¡¡¡¡¡¡antenna¡¡

stretches¡¡¡¡¡¡¡¡¡¡out¡¡¡¡¡¡over¡¡¡¡¡¡a¡¡¡¡distance¡¡¡¡¡¡¡¡of¡¡¡¡8£»400¡¡¡¡¡¡¡¡feet¡£¡¡¡¡It¡¡¡¡consists¡¡¡¡¡¡of¡¡¡¡¡¡372¡¡¡¡¡¡dual¡­¡¡

monopole¡¡vertical¡¡elements¡¡each¡¡19¡¡feet¡¡high£»¡¡backed¡¡by¡¡a¡¡huge¡¡reflector¡¡

screen¡¡which¡¡makes¡¡the¡¡antenna¡¡substantially¡¡unidirectional¡£¡¡Each¡¡pair¡¡of¡¡

vertical¡¡elements¡¡has¡¡its¡¡own¡¡receiver¡¡which¡¡digitizes¡¡the¡¡incoming¡¡signals¡£¡¡

All¡¡the¡¡digitized¡¡signals¡¡are¡¡then¡¡fed¡¡through¡¡a¡¡fibre¡­optic¡¡link¡¡to¡¡a¡¡master¡¡

signal¡¡¡¡¡¡¡¡¡¡processor¡£¡¡¡¡¡¡¡¡The¡¡¡¡¡¡¡¡main¡¡¡¡¡¡¡¡receiver¡¡¡¡¡¡can¡¡¡¡¡¡¡¡be¡¡¡¡programmed¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡to¡¡¡¡pass¡¡¡¡¡¡¡¡on¡¡



¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡87¡¡


¡­¡¡Page¡¡88¡­

¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡The¡¡dawn¡¡of¡¡amateur¡¡radio¡¡in¡¡the¡¡U¡£K¡£¡¡and¡¡Greece¡¡£º¡¡a¡¡personal¡¡view¡¡



¡¨returns¡¨¡¡¡¡¡¡from¡¡¡¡one¡¡¡¡¡¡particular¡¡¡¡¡¡region¡¡¡¡¡¡while¡¡¡¡¡¡eliminating¡¡¡¡¡¡most¡¡of¡¡¡¡¡¡the¡¡other¡¡

returns¡¡¡¡¡¡as¡¡¡¡¡¡unwanted¡¡¡¡¡¡noise¡¡¡¡¡¡or¡¡¡¡¡¡clutter¡£¡¡¡¡¡¡But¡¡¡¡¡¡because¡¡¡¡¡¡the¡¡¡¡¡¡wanted¡¡¡¡¡¡target¡¡¡¡¡¡is¡¡

moving£»¡¡while¡¡the¡¡clutter¡¡is¡¡not£»¡¡a¡¡filtering¡¡system¡¡based¡¡on¡¡the¡¡Doppler¡¡

Shift¡¡¡¡¡¡principle¡¡¡¡¡¡£¨even¡¡¡¡¡¡when¡¡¡¡¡¡the¡¡¡¡¡¡echo¡¡¡¡¡¡is¡¡¡¡¡¡only¡¡¡¡¡¡one¡¡¡¡¡¡or¡¡¡¡¡¡two¡¡¡¡¡¡Hertz¡¡¡¡¡¡different£©¡¡

will¡¡lock¡¡on¡¡to¡¡it¡¡and¡¡track¡¡it¡¡as¡¡long¡¡as¡¡it¡¡stays¡¡in¡¡motion¡£¡¡

¡¡¡¡¡¡¡¡¡¡¡¡¡¡Futhermore£»¡¡¡¡¡¡¡¡¡¡¡¡¡¡the¡¡¡¡¡¡ROTHR¡¡¡¡¡¡¡¡¡¡¡¡¡¡system¡¡¡¡¡¡¡¡¡¡has¡¡¡¡¡¡its¡¡¡¡own¡¡¡¡¡¡¡¡¡¡built¡­in¡¡¡¡¡¡automatic¡¡

management¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡&¡¡¡¡¡¡assessment¡¡¡¡¡¡¡¡¡¡¡¡function¡¡¡¡¡¡¡¡and¡¡¡¡¡¡does¡¡¡¡¡¡¡¡not¡¡¡¡¡¡have¡¡¡¡¡¡to¡¡¡¡¡¡depend¡¡¡¡¡¡¡¡on¡¡

external¡¡¡¡¡¡sounding¡¡¡¡¡¡data¡£¡¡¡¡¡¡It¡¡¡¡¡¡measures¡¡¡¡¡¡the¡¡¡¡¡¡ionosphere¡¡¡¡¡¡height¡¡¡¡¡¡continuously¡¡

and¡¡¡¡¡¡instantly¡¡¡¡¡¡selects¡¡¡¡¡¡the¡¡¡¡¡¡most¡¡¡¡¡¡appropriate¡¡¡¡¡¡frequency¡¡¡¡¡¡to¡¡¡¡¡¡use¡¡¡¡¡¡to¡¡¡¡¡¡scan¡¡¡¡¡¡the¡¡

target¡¡area£»¡¡ideally¡¡in¡¡one¡¡hop¡£¡¡

¡¡¡¡¡¡¡¡¡¡¡¡¡¡This¡¡automatic¡¡function¡¡uses¡¡a¡¡quasi¡­vertical¡¡incidence¡¡sounder¡¡£¨QVI£©¡¡

to¡¡measure¡¡the¡¡height¡¡of¡¡the¡¡ionosphere¡¡near¡¡the¡¡transmitting¡¡and¡¡receiving¡¡

sites£»¡¡¡¡¡¡¡¡which¡¡¡¡¡¡¡¡¡¡as¡¡¡¡mentioned¡¡¡¡¡¡¡¡¡¡¡¡¡¡earlier¡¡¡¡¡¡can¡¡¡¡¡¡¡¡be¡¡¡¡¡¡miles¡¡¡¡¡¡¡¡apart£»¡¡¡¡¡¡and¡¡¡¡¡¡¡¡a¡¡¡¡radar¡¡

backscatter¡¡¡¡¡¡sounder¡¡¡¡¡¡to¡¡¡¡¡¡measure¡¡¡¡¡¡the¡¡¡¡¡¡height¡¡¡¡¡¡of¡¡¡¡¡¡the¡¡¡¡¡¡ionosphere¡¡¡¡¡¡downrange¡¡

500¡¡to¡¡1£»800¡¡nautical¡¡miles¡¡away¡£¡¡The¡¡incoming¡¡real¡­time¡¡data¡¡from¡¡these¡¡

soundings¡¡are¡¡compared¡¡with¡¡data¡¡stored¡¡in¡¡computer¡¡memory¡£¡¡Once¡¡real¡­¡¡

time¡¡data¡¡are¡¡matched¡¡to¡¡a¡¡model¡¡of¡¡the¡¡ionosphere£»¡¡the¡¡model¡¡can¡¡be¡¡used¡¡

to¡¡¡¡¡¡operate¡¡¡¡¡¡¡¡¡¡the¡¡¡¡¡¡system¡¡¡¡¡¡¡¡¡¡for¡¡¡¡the¡¡¡¡¡¡best¡¡¡¡¡¡results£»¡¡¡¡¡¡based¡¡¡¡¡¡¡¡¡¡on¡¡¡¡¡¡the¡¡¡¡¡¡prevailing¡¡

propagation¡¡conditions¡£¡¡The¡¡dat

·µ»ØĿ¼ ÉÏÒ»Ò³ ÏÂÒ»Ò³ »Øµ½¶¥²¿ ÔÞ£¨0£© ²È£¨0£©

Äã¿ÉÄÜϲ»¶µÄ