----- Original Message ----- From: "Anthony Monteiro" <aa...@comcast.net> To: <amsat-bb@amsat.org> Sent: Saturday, April 09, 2011 5:15 PM Subject: [amsat-bb] Re: Diplexer
> A "duplexor" is a device that allows both transmitting and > receiving over the same transmission line or antenna. It > may or may not be a passive device and it may or may not > be frequency selective. > > In WWII RADAR systems, a duplexor was used to allow > the transmitter and receiver on the same frequency to > share the same antenna. The duplexor was a waveguide > device that had special gas-filled tubes to quickly > switch the signal direction. > > 73, > Tony AA2TX > Hi Tony, AA2TX I have in my hands the Instruction Book for Radar Recognition Sets AN/UPX-6 of U.S. Navy Department Bureau of Ships. The UPX6 is a IFF transponder on board of aicrafts and was used in WWII for Identification of Friend or Foe. The UPX-6 can transmit from 1010-1030 MHz and receive from 1090-1110 MHz and allows both transmitting and receiving over the same transmission line and antenna via a circuit made of coax cable RG-58/CU that the manual calls a "DUPLEXER" and not a "duplexor". This "duplexer" is working on the fact that a transmission line, shorted at the far end a quarter wavelenght long for the incoming signal,represent infinite impedance (an open circuit) at the sending end of the line. The UPX-6 was converted in the early 1980's to be used on 1296 MHz and an interesting article written by W6NBI was published in Ham Radio Magazine march 1981 I modified it and I got 40 watt output.......not too bad for that epoch time ! Best 73" de i8CVS Domenico _______________________________________________ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
